Molecular cloning, expression and immunogenicity of a xenogenic chicken VEGFR-2 peptide in mice

Vascular endothelial growth factor receptor-2 (VEGFR-2) signaling is crucial for neovasculogenesis in tumor and other inflammatory diseases and hence a promising target for immunotherapy. The cDNA corresponding to the IG domain and 2^nd immunoglobulin-like domain of chicken VEGFR-2 protein was cloned and the recombinant peptide was expressed in E. coli. The recombinant peptide (48Kd) was purified by Ni-NTA affinity chromatography and dialyzed. The immunogenicity of the purified peptide was evaluated by western blot analysis of the polyclonal sera raised against it in mice and rabbit. The polyclonal sera detected the 48 Kd band in western blot both in IPTG-induced bacterial lysate and with purified recombinant peptide. The polyclonal sera also detected a 230Kd band in 4T1-tumor lysate indicating the specific reaction of the sera with murine VEGFR-2 receptor in tumor tissue. It may be concluded that the peptide could be used as a target immunogen for immunotherapy against cancer.