GM-CSF gene or B7-1 gene modified murine EL-4 cells vaccine

Objective: To study the vaccine potency of gene-modified tumor cells. Methods: The EL-4 lymphoma was transduced with recombinant retrovirus containing the murine GM-CSF gene or B7-1 gene. The effect of gene transduction on antitumor immunity was investigated. Results: Flow cytometry analysis showed that expression of their surface marker between wild-type EL-4 cells and gene transduced tumor cells was the same except for CD80 positive in B7-1 gene transduced cells. GM-CSF gene or B7-1 gene transduced EL-4 cells resulted in remarkable loss of tumorigenicity in syngenetic mice. The systemic protective immunity was induced against the challenge with EL-4/wt cells. Therapeutic vaccine with EL-4/GM-CSF or EL/7-1 cells could retard the growth of established early-stage EL-4/wt tumor significantly, but not retard the growth of late-stage EL-4/wt tumor. Irradiated GM-CSF gene transduced EL-4 cells showed strong vaccine effect against EL-4 cell challenge, but irradiated B7-1 gene transduced EL-4 cells showed weak vaccine effect. Remarkable cooperative antitumor effect against EL-4 cell challenge was observed when both irradiated EL-4/GM-CSF and EL-4/B7-1 were inoculated together. Conclusion: GM-CSF gene or B7-1 gene transduced BL-4 cells can be used as a good tumor vaccine. The combination of the two kinds of vaccine may have potential application value in human cancer treatment.