Enhanced tumor responses to dendritic cells in the absence of CD8-positive cells.

Wild-type mice immunized with MART-1 melanoma Ag-engineered dendritic cells (DC) generate strong Ag-specific immunity that has an absolute requirement for both CD8(+) and CD4(+) T cells. DC administration to CD8 alpha knockout mice displayed unexpectedly enhanced levels of protection to tumor challenge despite this deficiency in CD8(+) T cells and the inability to mount MHC class I-restricted immune responses. This model has the following features: 1) antitumor protection is Ag independent; 2) had an absolute requirement for CD4(+) and NK1.