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A role for CD4+ T cell derived IL‐2 in CD8+ T cell responses
Author(s) -
Wilson Elizabeth,
Livingstone Alexandra Marie
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.2_supplement.364
Subject(s) - priming (agriculture) , cytotoxic t cell , cd40 , il 2 receptor , cd8 , interleukin 21 , t cell , immunology , biology , antigen presenting cell , context (archaeology) , adoptive cell transfer , microbiology and biotechnology , antigen , immune system , in vitro , biochemistry , paleontology , botany , germination
Primary CD8+ T cell responses can be generated in the absence of help in the context of inflammation and infection, but the quality of the memory response is strongly enhanced by help from CD4+ T cells. In the absence of infection or overt inflammation, the primary CD8+ T cell response is often fully dependent on help. Here we describe a minimally inflammatory model system where help for primary endogenous CD8+ T cell responses to peptide‐pulsed DC is provided by adoptively transferred naive OT‐II TCR transgenic cells. For help to be effective, the OT‐II cells must express CD40L, and recognize antigen on the same DC as the endogenous CD8+ T cells. However, our data indicate that expression of CD40L is not sufficient to provide help. IL‐2‐deficient OT‐II cells upregulate CD40L in vitro in the absence of exogenous IL‐2, but they do not provide help when adoptively transferred in vivo. Moreover, wild type OT‐II cells can provide help when transferred into IL‐2‐deficient mice, but not CD25‐deficient mice, suggesting that CD4 + T cell‐derived IL‐2 plays a crucial role in the generation of primary CD8 + T cell responses in the absence of overt inflammation. Studies by others have shown that CD8+ T cells must respond to IL‐2 during priming to develop effective memory/protection. Our data show that CD4+ T cells can provide IL‐2 for the primary response, and we hypothesize that this is true for memory and secondary responses as well.