Screening Antigen Epitopes Of Vascular Endothelial Growth Factor From 12 Phage Display Peptide Library And Construct Mimotope Vaccination

Angiogenesis of tumor is significant to tumor growth, infiltration and metastasis. Tumor growth is two stage: avascular stage, vascular stage, when volume of tumor is larger than 1～2 mm3, it is vascular stage of tumor growth, tumor get nutritive material and discard metabolite by new vessels, then tumor growth up quickly and metastasis. Folkman propose hypothesis that antiangiogenesis could inhibit tumor growth, then this hypothesis was confirmed, hence, tumor therapy of antiangiogenesis was establish, development.This year, research of antiangiogenesis: inhibitor of VEGF/VEGFR; inhibitor of vascular endothelial cell proliferation; MMPI. Now, vascular endothelial growth factor(VEGF)are most effective and specific angiogenine, VEGF manufacture by tumor cells, vascular endothelial cell, and VEGF go to vascular endothelial cells by paracrine, then bind VEGFR, enhance vascular endothelial cell proliferation, growth, migration, ECM degradation, angiogenesis, it is important to tumor growth, so VEGF and VEGFR is the best target to antiangiogenesis. Bevacizumab (Avastin) is the first drug of monoclonal antibody target VEGF. Avastin are effective in the treatment of rectal cancer, colon carcinoma, nonsmall-cell lung cancer(NSCLC). However, Avastin, like other mAbs, han disadvantages in that Ambs therapy is expensive and to be repeatedly administered for long periods of time. So we construct therapy vaccine of VEGF, then induce Humoral immune reaction and produce antibody, neutralize VEGF, inhibit tumor growth, this way avoid disadvantage of mAbs.Active vaccination against self-molecules may be a promising next step in drug development as they may produce ongoing immune responses, avoid repeated administration, and may provide affordable medicines and broader patient acceptance. Molecule of mimotope is small, we can get it by chemical synthesis, compared to general vaccine and genetic engineering produce, cost is cheap, technology is simple, without oncogenicity, without esotoxin, without source of infection. This kind of vaccine is preponderance in future.In this study, we get mimotope of VEGF from phage display library by Avastin, sequence of mimotope is DHTLYTPYHTHP. This peptide could mimic the epitope that Avastin could bind. We conjugating 12 peptide with keyhole limpet hemocyanin (KLH) by GA, then we get vaccine KLH-12 peptide (KLH-12P), this epitope vaccine can induce humoral immunity in mice, and the blood serum could bind with VEGF, inhibit vascular endothelial cell proliferation, migration.