The cytolytic T lymphocyte response to trinitrophenyl-modified syngeneic cells. I. Evidence for antigen-specific helper T cells

Mice were primed subcutaneously with trinitrophenyl (TNP)-modified syngeneic spleen cells. Seven days later, spleen cells from these in vivo primed mice, or spleen cells from naive mice, were co-cultured with TNP-modified syngeneic cells. Spleen cells from the in vivo primed mice demonstrated augmented cytolytic T lymphocyte (CTL) activity. The spleens of these in vivo primed mice contained a population of radioresistant, antigen-specific, helper T cells. Specifically, spleen cells from these mice, after X-irradiation, were able to augment the in vitro CTL response of normal spleen cells to TNP-modified syngeneic cells.