Help for cytotoxic-T-cell responses is mediated by CD40 signalling.
Bennett, Sally R. M.; Carbone, Francis R.; Karamalis, Freda; Flavell, Richard A.; Miller, Jacques F. A. P.; Heath, William R.
[Letter]
Nature.
393(6684):478-480, June 4, 1998.
(Format: HTML)
Cytotoxic T lymphocytes (CTLs) which carry the CD8 antigen recognize antigens that are presented on target cells by the class I major histocompatibility complex.CTLs are responsible for the killing of antigen-bearing cells, such as virus-infected cells. Although CTL effectors can act alone when killing target cells, differentiation from naive CD8-positive T cells is often dependent on 'help' from CD4-positive helper T (TH) cells [1-4]. Furthermore, for effective CTL priming, this help must be provided in a cognate manner, such that both the TH cell and the CTL recognize antigen on the same antigen-presenting cell [2,4]. One explanation for this requirement is that TH cells are needed to convert the antigen-presenting cell into a cell that is fully competent to prime CTL [5]. Here we show that signalling through CD40 on the antigen-presenting cells can replace the requirement for TH cells, indicating that T-cell 'help', at least for generation of CTLs by cross-priming, is mediated by signalling through CD40 on the antigen-presenting cell.
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