Objective: To investigate the differences of tumorigenicity and metastasis of marine tumors with different immunogenicity by B7.1 gene transfer.
Method: Using retroviral-mediated gene transfer, we transduced B7.1 cDNA into a panel of murine tumor lines with different immunogenicity to study the effect of B7.1 costimulation on antitumor immunity.
Results: After transduced with B7.1 cDNA, the immunogenic T lymphoma EL4 regressed completely, and tumorgenicity of three nonimmunogenic tumors melanoma B16, mastocytoma P815 and mammary adenocarcinoma MA891 were significantly reduced in syngeneic mice. The experimental metastasis of B16 and spontaneous pulmonary metastasis of MA891 were profoundly suppressed. Moreover, immunization with B7.1 cDNA transduced B16 induced systemic immunity against subsequently inoculated parental B16 tumor, while this immunization method did not provide protective immunity against established parental B16 tumor.
Conclusion: Our results show that varied extent of antitumor immunity can be induced to abrogate or decrease tumorigenecity and metastasis through B7.1 gene transduction, depending on the immunogenic potential of tumors.