CD80 and neoplasm: Further, the proliferation of CD4+ or CD8+ T cells induced by the tumor-activated γδ T cells was blocked in a transwell experiment and anti-CD80/CD86 antibody blocking experiment (Figure 2(e); n = 3, all P < 0.01), suggesting that the effect of tumor-activated γδ T cells on CD4+ or CD8+ T cells is dependent on cell-cell contact and costimulatory molecule CD80/CD86.