Experimental study on the antitumor effect of mouse B7-1 gene.

Mouse B7-1 cDNA was cloned by RT-PCR from BALB/C mouse splenic cells and inserted into pcDNA3 to construct an eukaryotic expression vector. This constructor was named pCD-mB7-1, in which the B7-1 cDNA was identified to be consistent with the data from other researchers. pCD-mB7-1 plasmid was transfected into B16(F0) cells, and effective expression of mB7-1 in these tumor cells could be detected till the 6th month by RT-PCR and RNA hybridization. Specific cytotoxity assay of lymphocytes was conducted after culturing with tumor cells and the results demonstrated that B16 cells transfected with B7-1 gene were more effective than B16-wt and B16-neo in inducing specific cytotoxity of lymphocytes against B16-wt cells. It is suggested that expression of B7-1 gene in tumor cells could enhance the immunogenicity and induce the effective antitumor immunity.