Sci. STKE, 24 September 2002
Immunology Direct Assistance
Both B and T lymphocyte responses require support from specialized helper T lymphocytes, which mediate their effects via the cell-surface protein CD40. For B cells, this support involves direct interaction with helper T cells expressing CD40-ligand (CD40-L). For CD8+ T cells, such help has been assumed to depend on signals generated via CD40 on third-party antigen-presenting cells (APCs). Bourgeois et al. developed an in vivo system for priming CD8 responses in which CD40 was present on CD8+ T cells, but absent on APCs. As expected, CD4+ cells were required to supply help via CD40-L but could generate CD8+ T cell memory without the need for CD40 on APCs. The role for CD40 on CD8+ T cells, rather than on the APCs, indicates a direct form of help paralleling that used in B cell memory formation.
Citation: Direct Assistance. Sci. STKE 2002, tw353 (2002).
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882