Presentation of prostate tumor antigens by dendritic cells stimulates T-cell proliferation and cytotoxicity.

Dendritic cells (DCs) are "professional" antigen-presenting cells capable of stimulating T-cell proliferation and cytotoxicity when loaded with and presenting specific antigens, including tumor antigens. We demonstrated the stimulation of an autologous cytotoxic T-cell response elicited by DC loaded with autologous tumor cell lysate derived from primary prostate tumor. A candidate tumor antigen is prostate-specific membrane antigen (PSMA), which is overexpressed in prostate cancer patients. We identified a HLA-A2 motif in PSMA, isolated patient DC, loaded peptide into DC, and stimulated autologous T cells to proliferate. The ability to use DC for presentation of either tumor or peptide antigen in an HLA-restricted fashion in order to stimulate T-cell proliferation and cytotoxicity demonstrates the potential of this technology for development of a prostate cancer vaccine.