Inhibition of the growth of human melanoma xenografts in nude mice by human tumor-specific cytotoxic T-cells

Melanoma-specific T-cells (CTLs) are specifically cytotoxic for autologous tumor, when assayed in vitro. To examine their effectiveness in vivo, we tested the ability of these human T-cells to inhibit growth of human melanoma xenografts by using a Winn assay. Nude mice receiving specific CTLs (n = 10) demonstrated a dramatic inhibition of tumor growth. All treated mice were tumor-free at day 50 and nine remained tumor-free at day 65, vs. control mice (n = 10) with average tumor volumes of 321 mm3 and 808 mm3, respectively. To control for the possibility that a non-specific response to the human T-cells could inhibit tumor growth, an additional group received allospecific CTLs. There was no inhibition of tumor growth in this group (n = 8), with the average tumor volume of 2,768 mm3 at day 40 vs. 1,882 mm3 in the control group (n = 10). We conclude that these tumor-specific CTLs can inhibit tumor growth in vivo and may prove useful in the adoptive immunotherapy of melanoma.