Inductive requirements of Theileria parva-specific cytotoxic T lymphocytes

This paper determines whether contact between parasite-specific CD4+ T cells and CD8+ T cells is an essential requirement for helper function, additional experiments were performed using two-chamber culture plates incorporating semi-porous membranes. TpM were co-cultured with naive or immune CD8 + T cells in the outer chamber and with immune DC4 + T cells in the inner chamber. Cytotoxic activity was observed in cultures containing primed CD8 + T cells but was undetectable in those containing naive CD8 + T cells. This abservations suggests that while soluble factors derived from activated CD4 + T helper cells are sufficient for the activation of memory CTL, naive CD8 + T cells require actual cell contact. Whether this signifies the involvement of receptor-ligand interactions or is a reflection of a requirement for defined local cytokine concentrations is not clear.