Efficient induction of peptide-specific cytotoxic T lymphocytes by LPS-activated spleen cells

Lipopolysaccharides of Gram-negative bacteria are potent activators of B ce lls, dendritic cells and monocytes/macrophages. We have investigated the us e of LPS-activated spleen cells as antigen-presenting cells to induce CD8cytotoxic T lymphocytes in vivo that are reactive to MHC class I binding pe ptides, Compared with resting spleen cells, CTL induction was more efficien t and less variable for different peptides with LPS-activated spleen cells. Cytotoxic responses were specific for the immunized peptides and contained high affinity CD8+ T cells. The removal of dendritic cells and monocytes/m acrophages by Sephadex G10 column did not show profound effects on CTL indu ction, indicating that B-cell blasts were largely responsible. This easily accessible method should facilitate the screening of MHC class I binding pe ptides to determine whether or not the host's T-cell repertoire contains re active T cells.