Induction of Mouse Anti‐melanoma Cytotoxic and Suppressor T Cells in vitro by an Artificial Antigen, GM3‐lactone

We investigated the ability of GM3‐lactone liposomes to induce anti‐melanoma T cell responses in mice. GM3‐lactone liposomes, like murine B16 melanoma cells, induced anti‐melanoma cytotoxic T cells (CTL) and also suppressor T cells (Ts). A small dose of GM3‐lactone (0.0003 μg/ml) was enough to generate CTL in the in vitro primary response, whereas relatively large amounts of the antigen (0.03–0.3 μg/ml) were required for anti‐melanoma Ts induction. As the epitope for anti‐melanoma Ts is NeuAc but not NeuGc residue on GM3, and anti‐melanoma CTL are effectively induced by either GM3(NeuAc) or GM3(NeuGc)‐lactone liposomes, GM3(NeuGc)‐lactone or GM3(NeuGc) liposomes have potent activity as an artificial melanoma antigen to induce anti‐melanoma CTL in vitro.