Helper T cells, dendritic cells and CTL Immunity.
In this review, we examine the emerging view that all CTL responses depend on CD4 T-cell help for the generation of efficient memory. We further review the evidence that CD4 and CD8 T cells must recognize antigen on the same dendritic cell, and examine why this corecognition is required. Earlier studies have suggested that CD4 T cells must activate the dendritic cell via CD40 to license it for the capacity to prime CTL immunity. More recently, however, CD40 signalling of the CTL has been reported. Here, we argue that the main reason for corecognition of antigen on the dendritic cell may be related to the time taken to activate and release CD4 and CD8 T cells from their priming dendritic cell. CD4 T cells may only be capable of activating one dendritic cell during the period that CD8 T cells are primed. In this case, corecognition of this same dendritic cell would be essential.
Immunology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
Georg
G
Behrens
Ming
M
Li
Christopher M
CM
Smith
Gabrielle T
GT
Belz
Justine
J
Mintern
Francis R
FR
Carbone
William R
WR
Heath
D000818:Animals; D019013:CD40 Antigens / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D015398:Signal Transduction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism
D019013:CD40 Antigens