Affinity maturation binding protein of EGFR (epidermal growth factor receptor) and application
阅读说明：本技术 Egfr的亲和力成熟结合蛋白及应用 (Affinity maturation binding protein of EGFR (epidermal growth factor receptor) and application ) 是由 魏星 陈涛 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种抗人EGFR的亲和力成熟结合蛋白及应用。该亲和力成熟结合蛋白是氨基酸序列如SEQ ID NO:4所示的aEG22C4亲和力成熟结合蛋白；或是氨基酸序列如SEQ ID NO:2所示的aEG12E2亲和力成熟结合蛋白、氨基酸序列如SEQ ID NO:3所示的aEG13E8亲和力成熟结合蛋白和氨基酸序列如SEQ ID NO:1所示的aEG11A6亲和力成熟结合蛋白中的至少一种与aEG22C4亲和力成熟结合蛋白组合形成的结合蛋白。该亲和力成熟结合蛋白具有高亲和力、高特异性和低免疫原性,并且具有较好的稳定性,结构简单,易于进行工程化改造等优点,可更好地应用于结合蛋白药物的开发。(The invention discloses an affinity maturation binding protein for resisting human EGFR and application thereof. The affinity maturation binding protein is aEG22C4 affinity maturation binding protein with the amino acid sequence shown as SEQ ID NO. 4; or a binding protein formed by combining at least one of aEG12E2 affinity maturation binding protein with an amino acid sequence shown as SEQ ID NO. 2, aEG13E8 affinity maturation binding protein with an amino acid sequence shown as SEQ ID NO. 3 and aEG11A6 affinity maturation binding protein with an amino acid sequence shown as SEQ ID NO. 1 with aEG22C4 affinity maturation binding protein. The affinity mature binding protein has the advantages of high affinity, high specificity, low immunogenicity, good stability, simple structure, easy engineering modification and the like, and can be better applied to the development of binding protein drugs.)
1. An affinity maturation binding protein for human EGFR, characterized by: the affinity maturation binding protein of the human EGFR is aEG22C4 affinity maturation binding protein; or a binding protein formed from a combination of at least one of aEG12E2 affinity matured binding protein, aEG13E8 affinity matured binding protein, and aEG11A6 affinity matured binding protein and aEG22C4 affinity matured binding protein;
the amino acid sequence of the aEG11A6 affinity maturation binding protein is shown as SEQ ID NO 1;
the amino acid sequence of the aEG12E2 affinity maturation binding protein is shown as SEQ ID NO. 2;
the amino acid sequence of the aEG13E8 affinity maturation binding protein is shown as SEQ ID NO. 3;
the amino acid sequence of the aEG22C4 affinity maturation binding protein is shown as SEQ ID NO. 4.
2. The nucleotide sequence encoding an affinity maturation binding protein for anti-human EGFR according to claim 1, characterized in that: is a nucleotide sequence encoding said aEG22C4 affinity maturation binding protein; or a nucleotide sequence formed by combining at least one of a nucleotide sequence for coding the aEG12E2 affinity maturation binding protein, a nucleotide sequence for coding the aEG13E8 affinity maturation binding protein and a nucleotide sequence for coding the aEG11A6 affinity maturation binding protein with a nucleotide sequence for coding the aEG22C4 affinity maturation binding protein.
3. The nucleotide sequence encoding an affinity maturation binding protein for anti-human EGFR according to claim 2, characterized in that:
the nucleotide sequence of the aEG11A6 affinity maturation binding protein is shown as SEQ ID NO. 8;
the nucleotide sequence of the aEG12E2 affinity maturation binding protein is shown as SEQ ID NO. 9;
the nucleotide sequence of the aEG13E8 affinity maturation binding protein is shown as SEQ ID NO. 10;
the nucleotide sequence of the aEG22C4 affinity maturation binding protein is shown as SEQ ID NO. 11.
4. The method of claim 1 for preparing an anti-human EGFR affinity maturation binding protein, comprising the steps of: synthesizing the nucleotide for coding the anti-human EGFR affinity maturation binding protein by a gene synthesis method, then cloning the nucleotide onto an expression plasmid vector, and transforming the expression plasmid vector into host cells for expression and purification to obtain the anti-human EGFR affinity maturation binding protein; or directly synthesizing the anti-human EGFR affinity mature binding protein by a polypeptide synthesis method.
5. Use of the anti-human EGFR affinity maturation binding protein of claim 1 for the preparation of a medicament for the treatment of a disease characterized by EGFR overexpression.
6. Use of the anti-human EGFR affinity maturation binding protein according to claim 5, for the preparation of a binding protein medicament for the treatment of a disease characterized by EGFR overexpression, wherein: diseases characterized by overexpression of EGFR include autoimmune diseases and cancer.
7. Use of the anti-human EGFR affinity maturation binding protein according to claim 6, for the preparation of a binding protein medicament for the treatment of a disease characterized by EGFR overexpression, wherein: the cancer is an EGFR high expression tumor.
8. Use of the anti-human EGFR affinity maturation binding protein according to claim 7, for the preparation of a binding protein medicament for the treatment of a disease characterized by EGFR overexpression, wherein: the EGFR high-expression tumor comprises pancreatic cancer, breast cancer, bladder cancer, esophageal cancer, nasopharyngeal cancer, head and neck cancer, gastric cancer, colorectal cancer, prostatic cancer, lung cancer, ovarian tumor, cervical cancer, uterine cancer, liver cancer, spleen cancer, kidney cancer and brain cancer.
Technical Field
The invention belongs to the technical field of biology, and relates to an affinity maturation binding protein of human EGFR and application thereof.
Background
The term cancer was proposed over 400 years before the era and has not been overcome over 2000, and the threat to human health is now increasingly apparent. In recent years, studies have found that Epidermal Growth Factor (EGFR) is overexpressed in various solid tumor cells and plays an important role in the development and progression of cancer. EGFR overexpression is positively correlated with poor prognosis and drug resistance in a variety of cancers. Overexpression of EGFR in cancer cells leads to persistent activation of EGFR/EGF signaling pathway, thereby promoting proliferation, migration and invasion activities of cancer cells, and also promoting secretion of VEGF factors, and inducing microenvironment angiogenesis of cancer tissues. At present, the monoclonal antibody targeting EGFR has a good effect on the clinical treatment of non-small cell lung cancer, but because of the chimeric antibody, the monoclonal antibody has certain immunogenicity, and because of the low permeability of the molecular weight, the monoclonal antibody cannot effectively eliminate the tiny focus.
The affinity maturation binding protein is a genetically engineered antibody containing only a single domain, and can bind to an antigen with high affinity and specificity. The affinity mature binding protein is convenient to express in escherichia coli due to small molecular weight, and the production cost is greatly reduced. Meanwhile, the affinity maturation binding protein has a simple structure, has high tissue infiltration capacity and is beneficial to further modification. Therefore, the anti-EGFR affinity maturation binding protein has high medical application value in EGFR-targeted cancer treatment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an affinity maturation binding protein for resisting human EGFR.
Another objective of the invention is to provide an application of the affinity maturation binding protein for resisting human EGFR.
The purpose of the invention is realized by the following technical scheme: an affinity maturation binding protein for human EGFR that is an aEG22C4 affinity maturation binding protein; or a binding protein formed from a combination of at least one of aEG12E2 affinity matured binding protein, aEG13E8 affinity matured binding protein, and aEG11A6 affinity matured binding protein and aEG22C4 affinity matured binding protein;
the amino acid sequence of the aEG11A6 affinity maturation binding protein is shown as SEQ ID NO 1;
the amino acid sequence of the aEG12E2 affinity maturation binding protein is shown as SEQ ID NO. 2;
the amino acid sequence of the aEG13E8 affinity maturation binding protein is shown as SEQ ID NO. 3;
the amino acid sequence of the aEG22C4 affinity maturation binding protein is shown as SEQ ID NO. 4.
The nucleotide sequence for coding the affinity maturation binding protein of the anti-human EGFR is the nucleotide sequence for coding the aEG22C4 affinity maturation binding protein; or a nucleotide sequence formed by combining at least one of a nucleotide sequence for coding the aEG12E2 affinity maturation binding protein, a nucleotide sequence for coding the aEG13E8 affinity maturation binding protein and a nucleotide sequence for coding the aEG11A6 affinity maturation binding protein with a nucleotide sequence for coding the aEG22C4 affinity maturation binding protein.
The nucleotide sequence of the aEG11A6 affinity maturation binding protein is preferably shown as SEQ ID NO. 8.
The nucleotide sequence of the aEG12E2 affinity maturation binding protein is preferably shown as SEQ ID NO. 9.
The nucleotide sequence of the aEG13E8 affinity maturation binding protein is preferably shown as SEQ ID NO. 10.
The nucleotide sequence of the aEG22C4 affinity maturation binding protein is preferably shown as SEQ ID NO. 11.
aEG11A6：
MAQVQLLESGGGLVQPGGSLRLSCAASGDMLIPDNMSWVRQAPGKGLEWVSTIHKTNGSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCALRSRGLSSKYEYWGQGTLVTVSSAAA；
aEG12E2：
MAQVQLLESGGGLVQPGGSLRLSCAASGDMLIPDNMSWVRQAPGKGLEWVSTIHKTNGSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAGLRSRGLSSKYYCGQGTLVTVSSAAA；
aEG13E8：
MAQVQLLEAGGGLIQPGGSLRLSCAASGDMLIPDNMSWVRQAPGKGLEWVSTIHKTHGSTYYADSVKGRVTISRDNSKNTLYLQMNSLRAEDTAVYYCAGLRSRGLSSKYYWGQGTLVTVSSAAA；
aEG22C4：
MAQVQLLESGGGLVEPGGSLSLSCAASGDMLSPDNMTWVRQAPGKGLEWVSTIHKTDGSTYYADSVKGRFTISRENSKNTLYLQMNSLRAEDTAVYYCAGLRSRGLSSKYLEYWGQGTPVTVSSAAA；
Nucleotide sequence encoding aEG11a6 affinity maturation binding protein:
ATGGCCCAGGTGCAGCTGTTGGAGTCTGGGGGAGGCTTGGTACAGCCTGGGGGGTCCCTGCGTCTCTCCTGTGCAGCCTCCGGAGATATGCTTATCCCTGACAATATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGTCTAGAGTGGGTATCAACCATTCATAAGACTAACGGTAGCACATACTACGCAGACTCCGTGAAGGGCCGGTTCACCATCTCCCGTGACAATTCCAAGAACACGCTGTATCTGCAAATGAACAGCCTGCGTGCCGAGGACACCGCGGTATATTATTGCGCGTTGCGTAGTAGGGGGCTTAGTTCGAAGTATGAGTATTGGGGTCAGGGAACCCTGGTCACCGTCTCGAGCGCGGCCGCA；
nucleotide sequence encoding aEG12E2 affinity maturation binding protein:
ATGGCCCAGGTGCAGCTGTTGGAGTCTGGGGGAGGCTTGGTACAGCCTGGGGGGTCCCTGCGTCTCTCCTGTGCAGCCTCCGGAGATATGCTTATCCCTGACAATATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGTCTAGAGTGGGTATCAACCATTCATAAGACTAACGGTAGCACATACTACGCAGACTCCGTGAAGGGCCGGTTCACCATCTCCCGTGACAATTCCAAGAACACGCTGTATCTGCAAATGAACAGCCTGCGTGCCGAGGACACCGCGGTATATTATTGCGCGGGATTGCGTAGTAGGGGGCTTAGTTCGAAGTACTATTGTGGTCAGGGAACCCTGGTCACCGTCTCGAGCGCGGCCGCA；
nucleotide sequence encoding aEG13E8 affinity maturation binding protein:
ATGGCCCAGGTGCAGCTGTTGGAGGCTGGGGGAGGCTTGATACAGCCTGGGGGGTCCCTGCGTCTCTCCTGTGCAGCCTCCGGAGATATGCTTATCCCTGACAATATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGACTAGAGTGGGTATCAACCATTCATAAGACTCACGGGAGCACATACTACGCAGACTCCGTGAAGGGCCGGGTCACCATCTCCCGTGACAATTCCAAGAACACGCTGTATCTGCAAATGAACAGCCTGCGTGCCGAGGACACCGCGGTATATTATTGCGCGGGATTGCGTAGTAGGGGGCTTAGTTCGAAGTACTATTGGGGTCAGGGAACCCTGGTCACCGTCTCGAGCGCGGCCGCA；
nucleotide sequence encoding aEG22C4 affinity maturation binding protein:
ATGGCCCAGGTGCAGCTGTTGGAGTCTGGGGGAGGCTTGGTAGAGCCTGGGGGGTCCCTGAGTCTCTCCTGTGCAGCCTCCGGAGATATGCTTAGCCCTGACAATATGACCTGGGTCCGCCAGGCTCCAGGGAAGGGTCTAGAGTGGGTATCAACCATTCATAAGACTGACGGTAGCACATACTACGCAGACTCCGTGAAGGGCCGGTTCACCATCTCCCGTGAGAATTCCAAGAACACGCTGTATCTGCAAATGAACAGCCTGCGTGCCGAGGACACCGCGGTATATTATTGCGCGGGATTGCGTAGTAGGGGGCTTAGTTCGAAGTACCTGGAGTATTGGGGTCAGGGAACCCCGGTCACCGTCTCGAGCGCGGCCGCA。
the nucleotide sequences for coding the aEG11A6 affinity maturation binding protein, aEG12E2 affinity maturation binding protein, aEG13E8 affinity maturation binding protein and aEG22C4 affinity maturation binding protein respectively consist of 375 bases, 375 bases and 381 bases, and the correspondingly coded amino acids are 125 bases, 125 bases and 127 bases.
aEG11A6 affinity maturation binding protein contains 3 complementarity determining clusters, wherein the amino acid encoding CDR1 is DMLIPDNMS, the amino acid encoding CDR2 is TIHKTN, and the amino acid encoding CDR3 is LRSRGLSSKYEY. aEG12E2 affinity maturation binding proteins contain 3 complementarity determining groups, wherein the amino acid encoding CDR1 is DMLIPDNMS, the amino acid encoding CDR2 is TIHKTN, and the amino acid encoding CDR3 is GLRSRGLSSKYY. aEG13E8 affinity maturation binding proteins contain 3 complementarity determining clusters, wherein the amino acid encoding CDR1 is DMLIPDNMS, the amino acid encoding CDR2 is TIHKTH, and the amino acid encoding CDR3 is GLRSRGLSSKYY. aEG22C4 affinity maturation binding protein contains 3 complementarity determining groups, wherein the amino acid encoding CDR1 is DMLSPDNMT, the amino acid encoding CDR2 is TIHKTD, and the amino acid encoding CDR3 is GLRSRGLSSKYLEY.
aEG11A6 affinity maturation binding protein contains 4 framework regions: amino acid MAQVQLLESGGGLVQPGGSLRLSCAASG for FR1, WVRQAPGKGLEWVS for FR2 and WVRQAPGKGLEWVS for FR3
GSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCA, the amino acid encoding FR4 is WGQGTLVTVSSAAA. aEG12E2 affinity maturation binding proteins contain 4 framework regions: the amino acid encoding FR1 was MAQVQLLESGGGLVQPGGSLRLSCAASG, the amino acid encoding FR2 was WVRQAPGKGLEWVS, the amino acid encoding FR3 was GSTYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCA, and the amino acid encoding FR4 was CGQGTLVTVSSAAA. aEG13E8 affinity maturation binding proteins contain 4 framework regions: the amino acid encoding FR1 was MAQVQLLEAGGGLIQPGGSLRLSCAASG, the amino acid encoding FR2 was WVRQAPGKGLEWVS, the amino acid encoding FR3 was GSTYYADSVKGRVTISRDNSKNTLYLQMNSLRAEDTAVYYCA, and the amino acid encoding FR4 was WGQGTLVTVSSAAA. aEG22C4 affinity maturation binding protein contains 4 framework regions: the amino acid encoding FR1 was MAQVQLLESGGGLVEPGGSLSLSCAASG, the amino acid encoding FR2 was WVRQAPGKGLEWVS, the amino acid encoding FR3 was GSTYYADSVKGRFTISRENSKNTLYLQMNSLRAEDTAVYYCA, and the amino acid encoding FR4 was WGQGTPVTVSSAAA.
The preparation method of the anti-human EGFR affinity mature binding protein comprises the following steps: synthesizing the nucleotide for coding the anti-human EGFR affinity maturation binding protein by a gene (DNA) synthesis method, then cloning the nucleotide onto an expression plasmid vector, and transforming the expression plasmid vector into a host cell for expression and purification to obtain the anti-human EGFR affinity maturation binding protein; the anti-human EGFR affinity mature binding protein can also be directly synthesized by a polypeptide synthesis method.
The application of the anti-human EGFR affinity maturation binding protein in preparing a binding protein medicament for treating diseases characterized by EGFR overexpression.
The disease characterized by overexpression of EGFR is an autoimmune disease and/or cancer.
The cancer is an EGFR high expression tumor.
The EGFR high-expression tumor comprises pancreatic cancer, breast cancer, bladder cancer, esophageal cancer, nasopharyngeal cancer, head and neck cancer, gastric cancer, colorectal cancer, prostatic cancer, lung cancer, ovarian tumor, cervical cancer, uterine cancer, liver cancer, spleen cancer, kidney cancer and brain cancer.
Compared with the prior art, the invention has the following advantages and effects:
1. the affinity maturation binding protein which interacts with the EGFR extracellular part domain III and is screened from a human affinity maturation binding protein library by a phage display method can obtain the fully human monoclonal affinity maturation binding protein under the condition of immunizing a human body without using an antigen, has the molecular weight of about 13kDa, only contains a single structural domain, has high affinity, specificity and low immunogenicity, and can remarkably reduce the production cost of the binding protein and promote the application of the binding protein by expressing the binding protein by using a prokaryotic host with high expression of the binding protein.
2. The affinity maturation binding protein provided by the invention has the advantages of good stability, easiness in modification, better tissue infiltration capacity and the like.
3. The affinity mature binding protein provided by the invention is humanized, so that the affinity mature binding protein has no immunogenicity in a human body and can be better applied to the development of anti-tumor binding protein medicines.
4. The prokaryotic host with high expression of the affinity mature binding protein provided by the invention can be used for expressing the binding protein, so that the production cost of the binding protein can be obviously reduced, and the application of the binding protein is promoted.
Drawings
FIG. 1 is a graph of the results of screening and enrichment of a polyclonal ELISA assay binding protein library; wherein, the PBS wells are blank controls, the CXCR4 wells are coated with a synthetic CXCR4 polypeptide (as an unrelated antigen control), the EpCAM wells are coated with a synthetic EpCAM polypeptide (as an unrelated antigen control), and the EGFR wells are coated with a synthetic EGFR polypeptide; the primary antibody is polyclonal phage binding protein obtained by amplification and purification after each round of library screening, and the secondary antibody is an antibody of HRP-labeled anti-phage M13. The results show that: during the screening of antibody libraries from round 1 to round 5, the OD450nm values obtained by screening the libraries with EGFR polypeptide increased from round to round, indicating that the enrichment of EGFR antibody clones in the libraries obtained by screening with EGFR polypeptide gradually increased.
FIG. 2 is a graph showing the results of monoclonal phage ELISA screening positive clones that bind to EGFR polypeptide; wherein A is an ELISA result chart of 32 monoclonal phages, and each monoclonal comprises: PBS (blank control wells), EpCAM polypeptide (irrelevant antigen control wells), EGFR polypeptide (antigen wells of interest); b is a specific detection result graph of 5 binding proteins obtained by screening, and each monoclonal comprises: PBS (blank control well), IFN protein (irrelevant antigen control well), NGF protein (irrelevant antigen control well), CD28 protein (irrelevant antigen control well), CD31 protein (irrelevant antigen control well), CSF1R protein (irrelevant antigen control well), ICAM-1 protein (irrelevant antigen control well), EpCAM extracellular domain protein (irrelevant antigen control well), EGFR extracellular domain protein (target antigen well), EGFR polypeptide (target antigen well). The results in FIG. 2B show that: the 4 affinity mature binding proteins have higher binding capacity to EGFR polypeptides than the wild-type binding protein aEG4D 9.
FIG. 3 is an electrophoresis chart of SDS-PAGE proteins after purification of expression of affinity maturation binding proteins aEG11A6, aEG12E2, aEG13E8 and aEG22C 4; lane 1 is Marker, lane 2 is uninduced whole protein, lane 3 is induced whole protein, lane 4 is induced disrupted precipitate, lane 5 is induced disrupted supernatant, lane 6 is column-over protein, lane 7 is wash-off protein, and lanes 8-12 are elution proteins.
FIG. 4 is a graph showing the detection of binding of purified anti-EGFR affinity mature binding protein to EGFR polypeptide by ELISA; among these, PBS (blank control wells), 7 irrelevant antigen control wells: IFN protein, NGF protein, CD28 protein, CD31 protein, CSF1R protein, ICAM-1 protein and EPCAM-His protein, 2 antigen wells of interest: an EGFR-His protein and an EGFR polypeptide. The results show that: compared with wild-type binding protein aEG4D9, aEG22C4 has higher binding capacity with EGFR polypeptide, and aEG11A6, aEG12E2 and aEG13E8 have similar binding capacity with EGFR polypeptide. Furthermore, the binding of the 4 affinity matured binding proteins to unrelated antigens was not apparent, suggesting that the 4 affinity matured binding proteins were capable of specifically binding to EpCAM.
FIG. 5 is a graph showing the results of MTT assay for detecting the effect of anti-EGFR affinity maturation binding protein on cancer cell proliferation; wherein A is a graph of the effect of the anti-EGFR affinity maturation binding protein on the proliferation of A549 cells, B is a graph of the effect of the anti-EGFR affinity maturation binding protein on the proliferation of DU145 cells, and C is a graph of the effect of the anti-EGFR affinity maturation binding protein on the proliferation of MCF-7 cells; aHER2-13C1 and aVE201 as negative control binding proteins; *: p <0.05 vs 0 μ g/mL,.: p <0.01 vs 0 μ g/mL,.: p <0.001 vs 0 μ g/mL,.: p <0.0001 vs 0 μ g/mL (n ═ 3). The results show that: for a549 cells, aEG12E2, aEG13E8, and aEG22C4 were more effective at inhibiting tumor cell proliferation than wild-type binding protein aEG4D9 at a concentration of 25 μ g/mL. For DU145 cells, the 4 affinity maturation binding proteins had similar tumor cell proliferation inhibitory effects compared to aEG4D 9. For MCF-7 cells, aEG11A6 and aEG22C4 were more effective at inhibiting tumor cell proliferation when a concentration of 25 μ g/mL was used than aEG4D 9.
FIG. 6 is a diagram showing the results of detecting the effect of anti-EGFR affinity maturation binding protein on cancer cell apoptosis by flow cytometry and Annexin V/PI double staining; wherein A, C, E is a two-dimensional scattergram of apoptotic A549 cells, DU145 cells and MCF-7 cells, and B, D, F is a graph of the apoptosis ratio results obtained from A, C, E; each cell included a control no binding Protein (PBS), a panel of experimental binding proteins (50. mu.g/mL): aEG11a6, aEG12E2, aEG13E8, and aEG22C4, wild type binding proteome (50 μ g/mL): aEG4D9, negative control group of binding proteins (50. mu.g/mL): aHER2-13C1 and aVE 201; *: p <0.05 vs 0 μ g/mL,.: p <0.01 vs 0 μ g/mL,.: p <0.001 vs 0 μ g/mL,.: p <0.0001 vs 0 μ g/mL (n ═ 3). The results show that: for a549 cells, the 4 affinity mature binding proteins had similar ability to induce apoptosis compared to wild-type binding protein aEG4D 9. For DU145 cells, 4 affinity maturation binding proteins had a higher ability to induce apoptosis compared to aEG4D 9. For MCF-7 cells, aEG22C4 has a higher ability to induce apoptosis than aEG4D 9.
FIG. 7 is a graph showing the results of the Transwell method for detecting the effect of the binding protein on the migration of cancer cells; wherein A, C, E is a photo picture of cell migration results of A549, DU145 and MCF-7 after treatment of binding protein at each concentration; B. d, F are respectively the trend chart of the variation of the light absorption value obtained according to A, C, E. The results show that: the 4 anti-EGFR affinity maturation binding proteins can inhibit the migration of A549 cells, MCF-7 cells and DU145 cells, and the migration capacity of cancer cells can be gradually reduced along with the increase of the concentration of the 4 affinity maturation binding proteins.
FIG. 8 is a graph showing the results of the verification of the inhibition of tumor size by binding proteins using a lung cancer mouse model; wherein, A is a volume change curve chart of the tumor after administration, B is a tumor photo graph of each group at the end of the administration period, C is a tumor weight statistical graph of each group after the administration period is ended, D is a H & E staining and immunohistochemical staining result graph of each group of tumors after the administration period is ended, and E is an integrated optical density result obtained by calculation according to D; *: p <0.05 vs 0 μ g/mL,.: p <0.01 vs 0 μ g/mL,.: p <0.001 vs 0 μ g/mL,.: p <0.0001 for 0 μ g/mL (n-4, aEG4D9 (n-3)). The results show that: according to the tumor volume plot of fig. 8A, 2 anti-EGFR affinity mature binding proteins had better ability to inhibit tumor cell growth in vivo compared to wild-type binding protein aEG4D 9. From the tumor map of fig. 8B, 2 anti-EGFR affinity mature binding proteins had smaller tumors compared to wild-type binding protein aEG4D 9. According to the tumor weight plot of fig. 8C, 2 anti-EGFR affinity mature binding proteins had lower tumor weights compared to wild-type binding protein aEG4D 9. Based on the integrated optical density results of FIG. 8E immunohistochemical staining, 2 anti-EGFR affinity mature binding proteins were able to induce tumor cell apoptosis (C-caspase-3) more efficiently in vivo than wild type binding protein aEG4D 9. The 2 affinity mature binding proteins were able to inhibit tumor cell proliferation in vivo (Ki67) with no apparent effect on tumor tissue angiogenesis (CD 31).
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
The present invention will be described in further detail below with reference to specific examples and drawings, but the embodiments of the present invention are not limited thereto.
Example 1 construction of affinity maturation binding protein library
(1) The mutant library was constructed using wild-type binding protein aEG4D9 (having the nucleotide sequence shown in SEQ ID NO: 12) as a template. Mismatch-prone PCR was performed according to the GeneMorph II Random Mutagenesis Kit (GeneMorph II, Stratagene) instructions. The binding protein DNA was amplified by mismatch-prone PCR and SfiI restriction sites were introduced, primers were errorF1 (having the nucleotide sequence shown in SEQ ID NO: 16) and errorR1 (having the nucleotide sequence shown in SEQ ID NO: 17).
(2) The PCR product was purified by agarose gel electrophoresis.
(3) After separating the correct size bandAccording toGel Extraction Kit instructions for Gel recovery.
(4) The recovered DNA product is ready for use.
(5) SfiI enzyme was added to the mismatch-prone PCR product and pComb3XSS phagemid vector, respectively, and digested overnight at 50 ℃.
(6) And (3) purifying the error-prone PCR product subjected to enzyme digestion and the pComb3XSS phagemid vector by agarose gel electrophoresis.
(7) According toThe Gel Extraction Kit instruction was used to recover correctly sized PCR products that are prone to mismatch after digestion and digested pComb3XSS phagemid vectors.
(8) The mispairing PCR product after enzyme digestion is connected into a pComb3XSS vector by using T4 enzyme.
(9) The ligation product was transformed into electroporation competent bacteria.
(10) After completing the electrotransfer, the electrotransfer competent bacteria were quickly transferred to SOC medium and incubated at 37 ℃ for 1 h.
(11) The transformed bacteria were inoculated on LB solid medium containing ampicillin, and cultured overnight at 37 ℃.
(12) Single clones on the medium were randomly picked and confirmed by colony PCR and DNA sequencing to see if the library was successfully constructed.
(13) The clone count method calculates the library size.
Example 2 preparation of helper phage
(1) The glycerol-preserved TG1 E.coli clonal strain was removed from the-80 ℃ freezer, spread on antibiotic-free TYE plates by four-zone streaking, and cultured overnight by inversion at 37 ℃.
(2) One TG1 monoclonal strain was picked from the plate and inoculated into 5mL of 2 XTY (antibiotic-free) liquid medium, and cultured overnight at 230rpm at 37 ℃.
(3) TG1 bacterial liquid was transferred to 5mL of 2 XTY antibiotic-free medium at a volume ratio of 1:100In the medium, the cells were cultured at 37 ℃ and 230rpm for 2 hours (bacterial liquid OD)600About 0.5).
(4) 200 μ L of TG1 bacterial liquid (OD)6000.5 or so) to a 1.5mL centrifuge tube, 10 μ LKM13 helper phage (1 × 10) was added13pfu/mL), put into preheated 37 ℃ water for warm bath for 30 min.
(5) Preparing soft agar, cooling to about 40 ℃, pouring the TG1 bacterial liquid treated in the step (4) into the soft agar, mixing, pouring the mixture into a prepared TYE solid culture plate containing 50 mu g/mL kanamycin resistance, standing at room temperature to solidify the mixture, and carrying out inverted culture at 37 ℃ for 13 hours.
(6) Selecting a plaque, and adding 5ml of strain G1 (OD)6000.5), shaking at 230rpm and 37 deg.C for 2 h.
(7) The whole amount of the bacterial suspension obtained in step (6) was transferred to 500mL of 2 XTY medium, shake-cultured at 37 ℃ and 230rpm for 2 hours, and then 500. mu.L of kanamycin (concentration in the medium is 50. mu.g/mL) was added, and culture was carried out at 30 ℃ and 230rpm for 20 hours.
(8) Centrifuging the bacterial liquid at 3300g for 20min, collecting supernatant, mixing the supernatant with 20% (w/v) PEG/NaCl solution at a volume ratio of 1:4, and standing on ice for 4 h.
(9) Then, the mixture was centrifuged at 3300g for 30min, and the precipitate was collected, resuspended in 1mL of sterile PBS (pH 7.4, 0.01M), centrifuged at 4000g for 5min, and the supernatant was collected as helper phage.
Example 3 amplification of affinity maturation binding protein library
(1) 5mL of bacteria containing the binding protein library were thawed on ice, transferred to 500mLLB broth (containing 0.1% by mass/volume ampicillin and 1% by mass/volume glucose), and shake-cultured at 37 ℃ for 2.5 h.
(2) Adding in an amount of 2 × 1012pfu helper phage KM13 was cultured at 37 ℃ for 30 min.
(3)3200g was centrifuged for 10min and the supernatant discarded.
(4) Resuspended with fresh LB liquid medium (containing 0.1% by mass ampicillin and 1% by mass glucose). Shaking and culturing at 25 deg.C for 20 h.
(5)3200g was centrifuged for 20min and the supernatant was collected.
(6) The phage in the solution was precipitated by adding 20% (w/v) PEG/NaCl solution and placed on ice for 4 h.
(7)3200g was centrifuged for 30min and the phage pellet was collected.
(8) Sterile PBS resuspended phage pellet.
(9) The prepared library phage was stored at-80 ℃.
(10) The binding protein pool titers were measured. Using cloning techniques, it was estimated that the phages, after dilution to a certain concentration, infected TG1 E.coli in the logarithmic growth phase. The infected TG1 strain was plated on a solid plate containing ampicillin, incubated overnight at 37 ℃ and the titer of the library of binding proteins was calculated from the number of clones. The titer of the amplified binding protein library is 2.1 × 1013pfu/mL。
Example 4 screening of affinity matured binding protein libraries for anti-EGFR fragments
(1) Screening of anti-EGFR affinity maturation binding protein phage
1) EGFR polypeptides (purchased from shanghai bordetella, having the amino acid sequences as set forth in SEQ ID NO: 15) was added to one immune tube (Nunc) and an equal volume of PBS (control) was added to the other immune tube and coated overnight at 4 ℃.
2) All solutions were discarded and the immune tubes were washed with PBS.
3) BSA solution with a concentration of 2% (w/v) was added to the immune tube, and the tube was left at room temperature for 2 hours and then blocked.
4) All solutions were discarded and the immune tubes were washed with PBS.
5) Adding 5X 10 to the immune tube12PFU phage, room temperature for 1 h.
6) All solutions were discarded and the immune tubes were washed with PBST to wash away unbound phage.
7) Add 500. mu.L of 1mg/mL pancreatin solution to the immune tube, turn over for 10min at room temperature, collect the phage eluate.
8) And adding 125 mu L of collected phage eluate into 875 mu L of TG1 Escherichia coli liquid, mixing, and culturing at 37 ℃ for 30 min.
9) The bacterial suspension was applied to a TYE solid medium (containing 0.1% by mass/volume of ampicillin and 1% by mass/volume of glucose) at an appropriate dilution ratio, and the screening results were calculated.
10) The remaining bacterial suspension of step 9) was applied to another 1 TYE solid medium (containing ampicillin 0.1% by mass/volume and glucose 1% by mass/volume) and cultured overnight at 37 ℃.
11) 2mL of 2 XTY (containing 15% v/v glycerol) medium was added to the solid medium in step 10), and all the bacteria were scraped off and collected.
12) mu.L of the bacterial suspension obtained in step 11) was inoculated into 50mL of a fresh 2 XTY liquid medium (containing 0.1% by mass/volume of ampicillin and 1% by mass/volume of glucose), and shake-cultured at 37 ℃ for 2 hours.
13) After centrifugation at 3000g for 15min, the supernatant was discarded, and the pellet was resuspended in 2 XTY liquid medium (containing 0.1% w/v glucose, 0.1% w/v ampicillin and 0.05% w/v kanamycin), and shake-cultured at 25 ℃ and 230rpm for 20 hours.
14) Centrifuging at 3000g for 20min, taking 40mL of supernatant, pouring into a sterile 50mL centrifuge tube, adding 10mL of 20% (w/v) PEG/NaCl solution into the centrifuge tube, turning upside down, mixing, and cooling in ice for 4 h.
15) After 4h, the mixture was centrifuged at 4000g for 30min at 4 ℃ and the supernatant was decanted. Adding 1mL PBS to resuspend the precipitate, transferring to a 1.5mL centrifuge tube, centrifuging again at 4 deg.C and 10000g for 10min, collecting supernatant, and storing at 4 deg.C.
16) And 5 times of enrichment process, and repeating the steps 1) to 15). The selection was performed sequentially from the phage obtained in the previous round.
(2) Polyclonal phage ELISA
1) To a 96-well plate, 0.2 μ g/well of EGFR polypeptide was added, while a blank control well (PBS), a CXCR4 polypeptide (purchased from shanghai potatoy, inc.) independent antigen control well, and an EpCAM polypeptide (purchased from shanghai potatoy, inc.) independent antigen control well were set.
2) All solutions were discarded and washed with PBS.
3) BSA solution with concentration of 2% (w/v) was added and left to block for 2h at room temperature.
4) All solutions were discarded and washed with PBS.
5) Phage enriched in 5 rounds of selection obtained in step 16) of part (1) of example 4 were added to 96-well plates, and phage solutions were mixed with 2% (w/v) BSA blocking solution at a volume ratio of 1:3 in each round, each well containing 100. mu.L of the mixture, and incubated at room temperature for 1 h.
6) All solutions were discarded and PBST washed.
7) Mu. L M13-HRP (HRP-labeled M13 phage murine mAb diluted 1:10000 in 2% (w/v) BSA blocking solution) was added to each well and incubated at room temperature for 1 h.
8) All liquid was discarded and PBST washed.
9) TMB solution (Biyuntian, P0209) was added to each well for color development, and the mixture was left to stand at room temperature in the dark for 5 min.
10) The reaction was stopped by adding 50. mu.L of 1M dilute sulfuric acid per well.
11) The absorbance of OD450nm was measured on a microplate reader.
12) FIG. 1 is a graph of the results of screening and enrichment of binding protein libraries by polyclonal ELISA analysis. The results in FIG. 1 show that: during the screening of antibody libraries from round 1 to round 5, the OD450nm values obtained by screening the libraries with EGFR polypeptide increased from round to round, indicating that the enrichment of EGFR antibody clones in the libraries obtained by screening with EGFR polypeptide gradually increased.
Example 5 selection of monoclonal phages from the 5 th round enriched library for ELISA validation
(1) The phage obtained from round 5 selection were diluted.
(2) 100 mu L of diluent is infected with TG1 bacteria liquid in logarithmic phase and coated on plates, 992 monoclonal strains are randomly selected from the plates and respectively placed in 96-well culture plates for culture, 200 mu L of 2 XTY culture medium and one clone are cultured in a shaker at 37 ℃ and 230rpm overnight.
(3) Mu.l of each well was pipetted into a new 96-well plate and incubated, 200. mu.l of fresh 2 XTY medium was added to each well and shaken at 37 ℃ for 2 h.
(4) mu.L of the bacterial suspension was retained in each well of the old plate, and 100. mu.L of 30% (v/v) glycerol was added thereto, and the plate was stored at-80 ℃ for further use.
(5) The suspension was transferred to 1 1.5mL centrifuge tube and cultured for 2 hours.
(6) Add 50. mu.L of helper phage-containing 2 XTY medium to the centrifuge tube, mix well, and place in 37 ℃ water bath for 30 min.
(7) After centrifugation at 3000g for 10min, the supernatant was discarded, the pellet was resuspended in 2 XTY medium (containing 0.1% w/v glucose, 0.1% w/v ampicillin and 0.05% w/v kanamycin) at 200. mu.L, and the bacterial suspension was added to a new 96-well plate and cultured with shaking at 25 ℃ and 250rpm for 20 hours.
(8) Centrifuging at 3000g for 10min, collecting the supernatant of each well into a 1.5mL centrifuge tube, and storing at 4 ℃ for later use.
(9) A96-well immunoplate (containing 0.2. mu.g of EGFR polypeptide per well) was coated with EGFR polypeptide at 100. mu.L/well, and blank control wells (PBS) and EpCAM polypeptide-independent antigen control wells were set and coated overnight at 4 ℃.
(10) The remaining steps were carried out as in part (2) of example 4, steps 2) to 11).
(11) FIG. 2A shows the results of ELISA with 32 monoclonal phages.
(12) The positive clone obtained in step (11) was subjected to verification of the specificity of positive phage using a plurality of unrelated antigens according to steps (3) to (10), and only the antigens in step (9) were changed to IFN protein, NGF protein, CD28 protein, CD31 protein, CSF1R protein, ICAM-1 protein, EpCAM extracellular domain protein, EGFR extracellular domain protein, and EGFR fragment (all of the above proteins are purchased from tokyo-kyo technologies, inc., and the EGFR fragment is synthesized by shanghaita bio), with the results shown in fig. 2B. The positive clone with better specificity is sent to Huada Gene company for DNA sequencing. The sequenced DNA results were analyzed in NCBI OFR, excluding identical nucleotide sequences. Finally, 4 different DNA sequences were obtained and named aEG11A6, aEG12E2, aEG13E8 and aEG22C 4. The results in FIG. 2B show that: the 4 affinity mature binding proteins have higher binding capacity to EGFR polypeptides than the wild-type binding protein aEG4D 9.
Example 6 obtaining wild-type binding protein and negative control binding protein
In the early-stage experiment of the laboratory, a phage display technology is adopted, polypeptide synthesized by human epidermal growth factor receptor 2(Her2) and Vascular Endothelial Growth Factor (VEGF) is used as an antigen, a humanized binding protein phage library is screened by adopting the method, 2 clones which are not combined with the corresponding antigen are selected by ELISA, and negative control binding proteins aHER2-13C1 and aVE201 are respectively obtained.
The wild-type binding protein aEG4D9 in the experimental examples had the amino acid sequence shown in SEQ ID NO. 5. The nucleotide sequence of the aEG4D9 is shown as SEQ ID NO. 12. The binding proteins aHER2-13C1 (Her2 as antigen) and aVE201 (VEGF as antigen) used as negative controls in the experimental examples had the amino acid sequences shown in SEQ ID NO:6 and SEQ ID NO:7, respectively. The nucleotide sequences encoding aHER2-13C12 and aVE201 are shown in SEQ ID NO 13 and SEQ ID NO 14, respectively.
Example 7 prokaryotic expression and purification of affinity maturation binding proteins expressing anti-EGFR
(1) Preparation of BL21 competent cells
1) E.coil BL21(DE3) competent bacteria were carefully removed from the refrigerator and thawed on ice.
2) The inoculating loop is used for dipping bacteria liquid, and plate streaking is carried out on an LB solid culture medium. The medium was placed in a 37 ℃ incubator and inverted overnight.
3) The next day, single colonies were picked and inoculated into 5mL of fresh LB liquid medium and cultured overnight at 37 ℃ in a shaker at 220 rpm.
4) mu.L of the overnight-cultured bacterial suspension obtained in step 3) was added to 50mL of fresh LB liquid medium and shake-cultured at 37 ℃ and 220rpm with a shaker until OD600 became 0.5.
5) Centrifuging the bacterial liquid obtained in the step 4) at 4 ℃ for 5min at 3200g, and then removing the supernatant.
6) The bacterial precipitation was performed according to the instructions of the super competent cell preparation kit (Shanghai Biotech Co., Ltd.) to obtain competent bacteria.
(2) Construction of recombinant vector for affinity maturation binding protein
The nucleotide sequence encoding the anti-EGFR affinity maturation binding protein was synthesized by Soviken Biotechnology, Inc., cloned into pET22b by 5 'NcoI and 3' NotI, and the recombinant plasmid was transformed into E.coli DH5 α for screening to obtain a binding protein plasmid.
(3) Conversion of competent cells by recombinant vectors of affinity maturation binding proteins
1) E.coil BL21(DE3) competent bacteria were carefully removed from the refrigerator and thawed on ice.
2) Add 1. mu.L of the conjugated protein plasmid to 100. mu.L of the competent bacterial suspension of LE. oil BL21(DE3), and flick the EP tube with fingers to help the competent bacteria and plasmid mix well, and keep on ice for 30 min.
3) The EP tube was placed in a water bath at 42 ℃ for 2 min.
4) The EP tube was quickly transferred to ice and left for 2 min.
5) To the EP tube, 900. mu.L of fresh LB liquid medium was added, and the mixture was cultured at 37 ℃ and 200rpm for 1 hour.
6) 10000g of EP tube was centrifuged for 1min, and 950. mu.L of the supernatant was discarded.
7) After the cell pellet was resuspended, the pellet was applied to LB solid medium (containing 100. mu.g/mL ampicillin). The cells were cultured overnight by inversion in a 37 ℃ incubator.
(4) Prokaryotic expression and purification of affinity maturation binding proteins
1) BL21(DE3) containing the recombinant expression plasmid vector was picked up and inoculated into 5mL of LB liquid medium containing 1% (w/v) glucose and 100. mu.g/mL ampicillin and cultured overnight at 37 ℃ in a shaker at 230 rpm.
2) 4mL of the inoculum was inoculated into 400mL of fresh LB liquid medium (containing 100. mu.g/mL ampicillin), and cultured in an incubator at 37 ℃ for about 2.5 hours.
3) IPTG (final concentration of 0.5mM) was added to the culture broth, and the shake culture was continued in an incubator at 25 ℃ for about 6 hours.
4) The bacterial liquid is centrifuged for 5min at 5000g and 4 ℃, and the supernatant is discarded.
5) The cells were disrupted with an ultrasonic disruptor set to: the power is 40%, the protection temperature is 10 ℃, the time is 40min, the work is 4s, and the stop is 8 s.
6) The disrupted bacterial solution was centrifuged at 13000g and 4 ℃ for 30 min. Transfer supernatant for affinity maturation binding protein purification.
7) The column was washed with 10mL of ultrapure water to the Ni-NTA purification column.
8) Then 10mL of the lysis buffer was added to balance the column.
9) And adding the supernatant of the crushed bacterial liquid into a Ni-NTA purification column.
10) To the Ni-NTA purification column, 20mL of a washing buffer was added, and the impure protein was washed off.
11) 10mL of elution buffer was added to the Ni-NTA purification column, and the target protein eluted was collected.
12) The solution containing the protein of interest is transferred to a dialysis bag.
13) The dialysis bag was carefully sealed, placed in PBS solution and stirred at 4 ℃ for 24h at low speed.
14) Putting the dialyzed protein solution into an ultrafiltration tube, and centrifuging at 4000g and 4 ℃ for 40min to concentrate the protein.
15) And (4) storing the concentrated protein in a refrigerator at the temperature of-80 ℃ for later use.
16) The concentration of anti-EGFR affinity maturation binding protein was determined and the protein solution was adjusted to 2mg/mL with PBS for subsequent experiments.
17) FIG. 3 is an electrophoresis chart of SDS-PAGE proteins after the expression and purification of affinity maturation binding proteins.
(5) And detecting the binding of the purified anti-EGFR affinity mature binding protein and the EGFR polypeptide by using an ELISA method.
1) Coating 96-well immune plates with 0.2 mu g of IFN protein, NGF protein, CD28 protein, CD31 protein, CSF1R protein, ICAM-1 protein, EpCAM protein, EGFR protein and EGFR fragment (the proteins are provided by Beijing Yinqiao Shenzhou science and technology GmbH, and the fragments are provided by Shanghai Betay biology), wherein the volume of the coating solution is 100 mu L/well, meanwhile, a blank control well (PBS) is arranged, and the coating is carried out overnight at 4 ℃.
2) The remaining steps follow steps 2) -11) of the polyclonal phage ELISA procedure of example 4), replacing only the HRP-labeled anti-phage M13 antibody in step 7) with proteinA-HRP protein (diluted 1:5000 by volume), with the results shown in fig. 4. The results show that: compared with wild-type binding protein aEG4D9, aEG22C4 has higher binding capacity with EGFR polypeptide, and aEG11A6, aEG12E2 and aEG13E8 have similar binding capacity with EGFR polypeptide. Furthermore, the binding of the 4 affinity matured binding proteins to unrelated antigens was not apparent, suggesting that the 4 affinity matured binding proteins were capable of specifically binding to EpCAM.
EXAMPLE 8 Effect of affinity maturation of binding proteins on the proliferation of A549, DU145 and MCF-7 cells
(1) Cells in the logarithmic growth phase were collected, and the cell concentration was adjusted to 50000 cells/mL using DMEM medium containing 10% (v/v) FBS.
(2) 100. mu.L/well of the cell suspension was added to each 96-well plate. 5% CO2And culturing in a 37 ℃ cell culture box for 12 hours.
(3) All the culture solution was discarded, and 100. mu.L/well of DMEM medium containing 1% (v/v) FBS was added to each well, and cultured in a cell culture chamber at 37 ℃ for 6 hours.
(4) Corresponding concentrations of anti-EGFR affinity maturation binding protein, wild type binding protein (aEG4D9) or negative control binding protein (aHER2-13C1 or aVE201) were added per well. Each antibody was set at 4 concentrations: 0. mu.g/mL, 25. mu.g/mL, 50. mu.g/mL, and 100. mu.g/mL.
(5) The 96-well plate was placed in a 37 ℃ cell incubator for further 72 hours.
(6) All the culture medium was discarded, 100. mu.L of the medium and 20. mu.L of MTT solution were added to each well, and the cell culture chamber was continued for 4 hours at 37 ℃.
(7) All the media were discarded, 150. mu.L of DMSO was added to each well, and the plates were incubated on a decolorizing shaker for 10 min.
(8) The absorbance of OD570nm was measured on a microplate reader.
The results in FIG. 5 show that: for a549 cells, aEG12E2, aEG13E8, and aEG22C4 were more effective at inhibiting tumor cell proliferation than wild-type binding protein aEG4D9 at a concentration of 25 μ g/mL. For DU145 cells, the 4 affinity maturation binding proteins had similar tumor cell proliferation inhibitory effects compared to aEG4D 9. For MCF-7 cells, aEG11A6 and aEG22C4 were more effective at inhibiting tumor cell proliferation when a concentration of 25 μ g/mL was used than aEG4D 9.
EXAMPLE 9 Effect of affinity maturation of binding proteins on apoptosis of A549, DU145 and MCF-7 cells
(1) Cells in logarithmic growth phase were collected. Cell concentration was adjusted to 1.25X 10 with DMEM medium containing 10% (v/v) FBS5one/mL.
(2) 2 mL/well of the cell suspension was added to a 6-well plate, and the 6-well plate was placed in a 37 ℃ cell incubator for 12 hours.
(3) All the culture was discarded, DMEM medium containing 1% (v/v) FBS was added to each well, and the 6-well plate was placed in a cell culture chamber at 37 ℃ for 6 h.
(4) 2mL of anti-EGFR affinity maturation binding protein, wild type binding protein (aEG4D9), or negative control binding protein at a concentration of 50 μ g/mL was added per well.
(5) The 6-well plate was placed in a 37 ℃ cell incubator for 48 h.
(6) All the culture medium was discarded and cells were collected after trypsinization.
(7) The operation is carried out according to the instruction of the apoptosis (Annexin V/PI double staining method kit, Shanghai Biotech engineering Co., Ltd.) detection kit.
(8) Apoptosis was detected using a flow cytometer.
The results are shown in FIG. 6: FIG. A, C, E is a two-dimensional scatter plot of apoptotic A549, DU145 and MCF-7 cells, respectively, showing an increase in apoptotic cells over both the no binding protein control and the negative control binding protein (right half); FIG. B, D, F is the apoptosis ratios obtained from FIG. A, C, E, respectively. The results in FIG. 6 show that: for a549 cells, the 4 affinity mature binding proteins had similar ability to induce apoptosis compared to wild-type binding protein aEG4D 9. For DU145 cells, 4 affinity maturation binding proteins had a higher ability to induce apoptosis compared to aEG4D 9. For MCF-7 cells, aEG22C4 has a higher ability to induce apoptosis than aEG4D 9.
EXAMPLE 10 Effect of affinity maturation of binding proteins on cell migration of A549, DU145 and MCF-7
(1) The Transwell chamber was placed in a 24-well cell culture plate.
(2) The cell culture solution was discarded, and fresh DMEM medium containing 1% (v/v) FBS was added and cultured in a cell culture chamber at 37 ℃ for 6 hours.
(3) The cells were collected by trypsinization, and the cell concentration was adjusted to 5X 10 in DMEM medium containing 1% (v/v) FBS5one/mL.
(4) To each chamber upper layer was added 100. mu.L of cell suspension and corresponding concentrations of anti-EGFR affinity maturation binding protein, wild type binding protein (aEG4D9) or negative control binding protein.
(5) DMEM medium containing 20% (v/v) FBS was added to the lower chamber layer.
(6) The 24-well cell culture plate was placed in a cell culture chamber at 37 ℃ for 24 hours.
(7) The medium above the chamber was discarded and the cotton swab wiped to remove the cells above the chamber.
(8) The lower layer of the cell was added with 4% (w/v) paraformaldehyde solution and left to stand for 15 min.
(9) The 4% (w/v) paraformaldehyde solution was discarded.
(10) The lower layer of the chamber was added with 2% (w/v) crystal violet solution and incubated for 30min in the dark.
(11) The chamber was placed on a glass slide and the microscope photographed.
(12) The lower layer of the cell was added with a 33% acetic acid solution. The absorbance of OD570nm was measured on a microplate reader.
The results in FIG. 7 show that: the 4 anti-EGFR affinity maturation binding proteins can inhibit the migration of A549 cells, MCF-7 cells and DU145 cells, and the migration capacity of cancer cells can be gradually reduced along with the increase of the concentration of the 4 affinity maturation binding proteins.
Experimental example 11 Effect of affinity maturation of binding proteins on mouse Lung cancer model
(1) Pancreatin digestion collects a549 cells in logarithmic growth phase.
(2) Cells were washed 2 times with sterile PBS solution.
(3) The cells were resuspended in DMEM medium without FBS and the density adjusted to 5X 107one/mL.
(4) Male Balb/C nude mice (purchased from Beijing Huafukang Biotechnology GmbH) at 4 weeks were selected, and 100. mu.L of cell suspension was aspirated by a disposable syringe and injected into the right axilla of the mice.
(5) Every 3 daysTumor volume in mice (mm) was measured once3)＝a×b2×0.5。
(6) When the mean tumor volume of the mice is about 100mm3Thereafter, the mice were randomly divided into 6 groups of 5 mice each. Corresponding drugs, including PBS, negative control binding protein (aHER2-13C1), wild type binding protein (aEG4D9), anti-EGFR affinity maturation binding protein (aEG11a6 or aEG22C4), or cisplatin (DDP) were injected separately. The injection is administered via the tail vein via an insulin needle. The injection volume was 100. mu.L, and was administered every 3 days.
(7) After the experiment was completed, the mice were sacrificed by cervical dislocation. After tumor tissue was dissected, photographs were taken and tumor weight was measured.
(8) Tumor tissues were fixed by immersion in 4% (w/v) paraformaldehyde.
(9) Tumor tissue was transferred to gradient ethanol (50%, 70%, 85%, 95%, 100%) for dehydration.
(10) The tumor tissue is soaked in xylene-ethanol (volume ratio 1:1) for 2 hours.
(11) The tumor tissue was soaked in xylene for 1 h.
(12) Tumor tissues were embedded in paraffin.
(13) The paraffin embedded tumor tissue was cut to a thickness of 6 μm on a microtome.
(14) Paraffin sections were dewaxed.
(15) The sections were placed in hematoxylin dye for 5 min. Excess dye is washed away.
(16) The sections were placed in differentiation medium for 30 s.
(17) The sections were placed in eosin dye for 1 min.
(18) Sections were dehydrated in gradient ethanol (70%, 85%, 95%, 100%).
(19) And (6) dropwise adding a gum sealing sheet.
(20) And (4) placing the section obtained in the step (14) in sodium citrate repairing solution with the pH value of 6.0 for antigen repairing.
(21) The sections were incubated in hydrogen peroxide at room temperature.
(22) The sections were placed in blocking solution and blocked at room temperature for 10 min.
(23) Sections were incubated overnight at 4 ℃ in primary antibody (Ki67, CD31 or Caspase3) working solution.
(24) The sections were incubated in secondary antibody working solution at 37 ℃ for 30 min.
(25) And (4) placing the section in a DAB developing solution, and incubating for 10min at room temperature.
(26) Hematoxylin was added for counterstaining.
(27) The steps of dehydration and mounting are the same as the steps (18) to (19).
(28) Photographs were taken under the microscope and analyzed by Image pro plus software.
The results in FIG. 8 show that: according to the tumor volume plot of fig. 8A, 2 anti-EGFR affinity mature binding proteins had better ability to inhibit tumor cell growth in vivo compared to wild-type binding protein aEG4D 9. From the tumor map of fig. 8B, 2 anti-EGFR affinity mature binding proteins had smaller tumors compared to wild-type binding protein aEG4D 9. According to the tumor weight plot of fig. 8C, 2 anti-EGFR affinity mature binding proteins had lower tumor weights compared to wild-type binding protein aEG4D 9. Based on the integrated optical density results of FIG. 8E immunohistochemical staining, 2 anti-EGFR affinity mature binding proteins were able to induce tumor cell apoptosis (C-caspase-3) more efficiently in vivo than wild type binding protein aEG4D 9. The 2 affinity mature binding proteins were able to inhibit tumor cell proliferation in vivo (Ki67) with no apparent effect on tumor tissue angiogenesis (CD 31).
The reagents used in the examples were configured as follows:
(1)PBS/PBST(pH7.4)：KH2PO40.24g、NaCl8g、KCl0.2g、Na2HPO4·12H2O9.07g。
the reagent is weighed, 900mL of deionized water is added for dissolving, and the volume is determined to be 1L. If aseptic conditions are required, the product can be sterilized at 121 deg.C under high temperature and high pressure, and stored at 4 deg.C.
PBST: adding Tween-20 with final concentration of 0.1% into the prepared PBS buffer solution, mixing, sterilizing at 121 deg.C under high temperature and high pressure, and storing at 4 deg.C.
(2) TBS/TBST: tris base 6.05g, NaCl21.93g.
The reagent is dissolved by 400mL of deionized water, the pH value is adjusted to 7.4 by dilute hydrochloric acid, and the volume is adjusted to 500 mL.
TBST: add 500. mu.L Tween-20 to 500mL TBS buffer and mix well.
(3) LB liquid medium: NaCl2g, tryptone 2g, yeast extract 1g, and ultrapure water 200 mL.
Mixing the above reagents, autoclaving at 121 deg.C, and storing at 4 deg.C.
LB solid medium: 4g of agar powder is added into the LB liquid culture medium.
(4) 20% glucose: 200g of glucose powder was weighed, dissolved in 1L of deionized water, sterilized by filtration using a 0.22. mu.M filter, and stored at-4 ℃.
(5) 100. mu.g/mL ampicillin solution: 1g of the powder was weighed, dissolved in 10mL of deionized water to prepare a 100mg/mL solution, sterilized by filtration using a 0.22. mu.M filter, and dispensed into 1mL tubes and stored at-20 ℃.
(6) SDS-PAGE electrophoresis: 94g of glycine, 30.2g of Tris base and SDS5 g.
The reagent was dissolved in 900mL of deionized water to a volume of 1L. The reagent is 5 Xelectrophoresis solution formula, and is stored at 4 ℃. In use, ddH is used2Diluting O to 1X.
(7) SDS-PAGE membrane-transfer solution: 15.14g of Tris alkali and 72g of glycine.
The reagent is dissolved by 900mL of deionized water, the volume is constant to 1L, and the solution is stored at 4 ℃. The reagent is 5 × electrophoresis solution formula, and is diluted to 1 × with ultrapure water when in use.
(8)500M IPTG: 11.915g of IPTG powder was weighed, dissolved in 100mL of deionized water, sterilized by filtration using a 0.2 μm filter, and dispensed into 1mL tubes and stored at-20 ℃.
(9)1MH2SO4:10 mL of concentrated sulfuric acid was slowly added to 187mL of deionized water.
(10)100 × PMFS: 1.74g of PMSF was weighed out and dissolved in 100mL of isopropanol and stored at-20 ℃.
(11) Protein expression purification buffer
And (3) breaking the bacteria buffer solution: 2.42g of Tris base, 14.6g of NaCl14.6g and 100 XPMSF 10 mL.
The above reagent was dissolved in 900mL of ultrapure water, the pH was adjusted to 7.45 with dilute hydrochloric acid, the volume was adjusted to 1L, and the solution was stored at 4 ℃.
Loading buffer solution: and (4) breaking the bacteria in the buffer solution.
Washing with a miscellaneous buffer solution: 20mL of the loading buffer was added with 200. mu.L of imidazole stock solution (2M).
Elution buffer: 9mL of the loading buffer was added with 1mL of imidazole mother liquor (2M).
(12) 2% BSA: 2% bovine serum albumin powder (w/v) was added to the PBS buffer.
(13) 30% glycerol solution (glycerol-PBS): 15mL of glycerol was measured, and 35mL of PBS buffer (pH 7.4) was added thereto, followed by filtration sterilization using a 0.22 μm filter and storage at 4 ℃.
(14) 10% Ammonium Persulfate (APS): ammonium sulfate 0.5g, ddH2O5mL。
Mixing the above reagents, packaging into 500 μ L tubes, and storing at-20 deg.C.
(15)1M Tris-Hcl (PH 8.8/PH 6.8): weighing 0.2g Tris-Base powder, dissolving in 900mL deionized water, adjusting pH to 6.8 or 8.8 with dilute hydrochloric acid, diluting to 1L, sterilizing at high temperature and high pressure, and storing at 4 deg.C.
(16) Coomassie brilliant blue dye liquor: coomassie brilliant blue R-2501g, isopropanol 250mL, glacial acetic acid 100mL, ddH2O650mL。
(17) Coomassie brilliant blue staining destaining solution: glacial acetic acid 100mL, ethanol 50mL, ddH2O850mL。
(18)5 × protein Loading buffer (Loading buffer): 1M Tris-HClPH 6.812.5mL, SDS5g, bromophenol blue 0.25g, and glycerol 25 mL.
To the above reagent was added ddH2And O, diluting to 50mL, and storing at room temperature. Before use, 500. mu.L of beta-mercaptoethanol was added, optionally 25. mu.L.
(19) TYE solid medium (400 mL): 5g of peptone, 2.5g of yeast powder, 4g of agar powder and ddH2O400mL。
Mixing the above reagents, sterilizing at 121 deg.C under high temperature and high pressure, cooling to 50 deg.C, adding 1% glucose solution and 100 μ g/mL ampicillin, mixing, pouring into flat plate, and storing in refrigerator at 4 deg.C.
(20)2 × TY Medium (100 mL): peptone 1.6g, yeast powder 1g, NaCl0.5g, ddH2O100mL。
Mixing the above reagents, sterilizing at 121 deg.C under high temperature and high pressure, and storing at 4 deg.C.
(21) 20% PEG/NaCl solution (500 mL): PEG600100g, NaCl73g, ddH2O400mL。
Dissolving in deionized water, diluting to 500mL, sterilizing at 121 deg.C for 20min, and storing at room temperature.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Sequence listing
<110> river-south university
<120> affinity maturation binding proteins for EGFR and uses thereof
<160> 17
<170> SIPOSequenceListing 1.0
<223> aEG11A6 amino acid sequence of affinity maturation binding protein
<400> 1
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Asp Met Leu Ile
20 25 30
Pro Asp Asn Met Ser Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Thr Ile His Lys Thr Asn Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Leu Arg Ser Arg Gly Leu Ser Ser Lys Tyr Glu Tyr Trp
100 105 110
Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> aEG12E2 amino acid sequence of affinity maturation binding protein
<400> 2
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Asp Met Leu Ile
20 25 30
Pro Asp Asn Met Ser Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Thr Ile His Lys Thr Asn Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Gly Leu Arg Ser Arg Gly Leu Ser Ser Lys Tyr Tyr Cys
100 105 110
Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> aEG13E8 amino acid sequence of affinity maturation binding protein
<400> 3
Met Ala Gln Val Gln Leu Leu Glu Ala Gly Gly Gly Leu Ile Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Asp Met Leu Ile
20 25 30
Pro Asp Asn Met Ser Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Thr Ile His Lys Thr His Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Val Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Gly Leu Arg Ser Arg Gly Leu Ser Ser Lys Tyr Tyr Trp
100 105 110
Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> aEG22C4 amino acid sequence of affinity maturation binding protein
<400> 4
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Glu Pro
1 5 10 15
Gly Gly Ser Leu Ser Leu Ser Cys Ala Ala Ser Gly Asp Met Leu Ser
20 25 30
Pro Asp Asn Met Thr Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Thr Ile His Lys Thr Asp Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Glu Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Gly Leu Arg Ser Arg Gly Leu Ser Ser Lys Tyr Leu Glu
100 105 110
Tyr Trp Gly Gln Gly Thr Pro Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> aEG4D9 amino acid sequence of wild-type binding protein
<400> 5
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Asp Met Leu Ser
20 25 30
Pro Asp Asn Met Thr Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Thr Ile His Lys Thr Asp Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Gly Leu Arg Ser Arg Gly Leu Ser Ser Lys Tyr Leu Glu
100 105 110
Tyr Trp Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> amino acid sequence of aHER2-13C1 negative control binding protein
<400> 6
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Tyr Ser Val Ser
20 25 30
Ser Glu Asn Met Gly Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Gly Ile Leu Ala Gly Asp Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Arg Phe Thr Ser Gly Gln Gly Ser Leu Arg Ser Asp Pro
100 105 110
Ile Arg Ser Trp Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala
115 120 125
Ala
<223> aVE201 amino acid sequence of negative control binding protein
<400> 7
Met Ala Gln Val Gln Leu Leu Glu Ser Gly Gly Gly Leu Val Gln Pro
1 5 10 15
Gly Gly Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Val Ser Val Ser
20 25 30
Asn Glu Ala Met Gly Trp Val Arg Gln Ala Pro Gly Lys Gly Leu Glu
35 40 45
Trp Val Ser Ser Ile Thr Asp Gln Ser Gly Ser Thr Tyr Tyr Ala Asp
50 55 60
Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn Thr
65 70 75 80
Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val Tyr
85 90 95
Tyr Cys Ala Arg Gly Gln Arg Arg Arg Gln Met His Ser Tyr Lys Val
100 105 110
Ser Ser Trp Gly Gln Gly Thr Leu Val Thr Val Ser Ser Ala Ala Ala
115 120 125
<223> nucleotide sequence encoding aEG11A6 affinity maturation binding protein
<400> 8
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggagatatg cttatccctg acaatatgag ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaaccattc ataagactaa cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcgttg 300
cgtagtaggg ggcttagttc gaagtatgag tattggggtc agggaaccct ggtcaccgtc 360
tcgagcgcgg ccgca 375
<223> nucleotide sequence encoding aEG12E2 affinity maturation binding protein
<400> 9
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggagatatg cttatccctg acaatatgag ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaaccattc ataagactaa cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcggga 300
ttgcgtagta gggggcttag ttcgaagtac tattgtggtc agggaaccct ggtcaccgtc 360
tcgagcgcgg ccgca 375
<223> nucleotide sequence encoding aEG13E8 affinity maturation binding protein
<400> 10
atggcccagg tgcagctgtt ggaggctggg ggaggcttga tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggagatatg cttatccctg acaatatgag ctgggtccgc 120
caggctccag ggaagggact agagtgggta tcaaccattc ataagactca cgggagcaca 180
tactacgcag actccgtgaa gggccgggtc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcggga 300
ttgcgtagta gggggcttag ttcgaagtac tattggggtc agggaaccct ggtcaccgtc 360
tcgagcgcgg ccgca 375
<223> nucleotide sequence encoding aEG22C4 affinity maturation binding protein
<400> 11
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tagagcctgg ggggtccctg 60
agtctctcct gtgcagcctc cggagatatg cttagccctg acaatatgac ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaaccattc ataagactga cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgagaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcggga 300
ttgcgtagta gggggcttag ttcgaagtac ctggagtatt ggggtcaggg aaccccggtc 360
accgtctcga gcgcggccgc a 381
<223> nucleotide sequence encoding aEG4D9 wild-type binding protein
<400> 12
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggagatatg cttagccctg acaatatgac ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaaccattc ataagactga cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcggga 300
ttgcgtagta gggggcttag ttcgaagtac ctggagtatt ggggtcaggg aaccctggtc 360
accgtctcga gcgcggccgc a 381
<223> nucleotide sequence encoding aHER2-13C1 negative control binding protein
<400> 13
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggatatagc gttagctctg agaatatggg ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaggcattt tggcgggaga cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcgaga 300
tttacgtcgg gtcaggggtc gttgcggtcc gaccccatcc ggtcttgggg tcagggaacc 360
ctggtcaccg tctcgagcgc ggccgca 387
<223> nucleotide sequence encoding aVE201 negative control binding protein
<400> 14
atggcccagg tgcagctgtt ggagtctggg ggaggcttgg tacagcctgg ggggtccctg 60
cgtctctcct gtgcagcctc cggagttagc gttagcaatg aggctatggg ctgggtccgc 120
caggctccag ggaagggtct agagtgggta tcaagcatta ctgaccaaag cggtagcaca 180
tactacgcag actccgtgaa gggccggttc accatctccc gtgacaattc caagaacacg 240
ctgtatctgc aaatgaacag cctgcgtgcc gaggacaccg cggtatatta ttgcgcgaga 300
gggcagcgtc gtaggcagat gcattcgtac aaggtcagct cttggggtca gggaaccctg 360
gtcaccgtct cgagcgcggc cgca 384
<223> amino acid sequence of EGFR antigen
<400> 15
Gln Ala Trp Pro Glu Asn Arg Thr Asp Leu His Ala Phe Glu Asn Leu
1 5 10 15
Glu Ile Ile Arg Gly Arg Thr Lys Gln His Gly Gln Phe Ser
20 25 30
<223> primer errorF1
<400> 16
actggcccag gcggccatgg cccaggtgca gctg 34
<223> primer errorR1
<400> 17
actggccggc ctggcctgcg gccgcgctcg agacg 35
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