TYR and melanoma: One of the best characterized is the Trp-1 model, in which CD4+ T cells expressing a transgenic MHC class II (MHCII)-restricted TCR specific for the tyrosinase related protein expressed by B16 melanoma were able to eradicate established tumors in lymphopenic hosts, via a direct cytotoxic attack against the B16 melanoma cells, with no requirement for CD8+ T cells or B cells [10].