CD4+ T cell help improves CD8+ T cell memory by retained CD27 expression

MS Matter, C Claus… - European journal of …, 2008 - Wiley Online Library
MS Matter, C Claus, AF Ochsenbein
European journal of immunology, 2008Wiley Online Library
CD4+ T cell help during the priming of CD8+ T lymphocytes imprints the capacity for optimal
secondary expansion upon re‐encounter with antigen. Helped memory CD8+ T cells rapidly
expand in response to a secondary antigen exposure, even in the absence of T cell help
and, are most efficient in protection against a re‐infection. In contrast, helpless memory CTL
can mediate effector function, but secondary expansion is reduced. How CD4+ T cells
instruct CD8+ memory T cells during priming to undergo efficient secondary expansion has …
Abstract
CD4+ T cell help during the priming of CD8+ T lymphocytes imprints the capacity for optimal secondary expansion upon re‐encounter with antigen. Helped memory CD8+ T cells rapidly expand in response to a secondary antigen exposure, even in the absence of T cell help and, are most efficient in protection against a re‐infection. In contrast, helpless memory CTL can mediate effector function, but secondary expansion is reduced. How CD4+ T cells instruct CD8+ memory T cells during priming to undergo efficient secondary expansion has not been resolved in detail. Here, we show that memory CTL after infection with lymphocytic choriomeningitis virus are CD27high whereas memory CTL primed in the absence of CD4+ T cell have a reduced expression of CD27. Helpless memory CTL produced low amounts of IL‐2 and did not efficiently expand after restimulation with peptide in vitro. Blocking experiments with monoclonal antibodies and the use of CD27–/– memory CTL revealed that CD27 ligation during restimulation increased autocrine IL‐2 production and secondary expansion. Therefore, regulating CD27 expression on memory CTL is a novel mechanism how CD4+ T cells control CTL memory.
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