嵌合表皮生长因子疫苗E5T-mSEA的设计及抑瘤活性检测

Design and activity analysis of chimeric epidermal growth factor fusion vaccine E5T-mSEA

摘要:

表皮生长因子受体(Epidermal growth factor receptor , EGFR)及其配体在多种肿瘤细胞中高表达，免疫注射表皮生长因子(Epidermal growth factor，EGF)-载体蛋白所产生的抗体能够干扰EGFR与EGF的相互作用，进而抑制肿瘤生长。本实验室设计了EGF和TGFα的嵌合配体E5T，并将具有免疫增强作用的葡萄球菌肠毒素A (Staphylococcal enterotoxin A，SEA) 与之融合。融合蛋白在大肠杆菌内表达后，通过金属螯合亲和层析，得到了纯度较高的E5T-mSEA融合蛋白。将E5T-mSEA免疫小鼠，能够产生高滴度的抗体，该抗体能够同时识别EGF和TGFα。将抗E5T-mSEA免疫血清与肿瘤细胞共培养，在1:10的稀释度下能显著抑制EGFR阳性肿瘤细胞的生长，而对EGFR阴性肿瘤细胞293T的生长没有明显影响。

Abstract:

Epidermal growth factor receptor (EGFR) and its ligands (EGF and TGFα) are over-expressed in a variety of tumors. Immunization EGF-carrier protein inhibits tumor growth through abrogating binding of EGF to EGFR. Here, a chimeric protein of EGF and TGFα (E5T) was genetically fused to Staphylococcal enterotoxin A (SEA), a bacterial superantigenic protein which promotes humoral B cell response through enhancement of Ag-specific CD4 T cells activity. The resulted fusion proteins were expressed in Escherichia coli and purified though metal chelating affinity chromatography. Immunization of E5T-mSEA fusion protein in mice induced production of high titers antibodies, which recognize both EGF and TGFα. Anti- E5T-mSEA serum at dilution of 1:10 significantly inhibited growth of A431 cell lines but had little effect on 293T cell lines.