The response of gamma delta T cells to Plasmodium falciparum is dependent on activated CD4+ T cells and the recognition of MHC class I molecules.
Peripheral blood gamma delta T cells from non-exposed individuals respond to antigens of the malaria parasite, Plasmodium falciparum, in vitro. This response, largely caused by T cells bearing the V gamma 9+ chain of the T-cell receptor, is stimulated by components of the parasite expressed on the schizont stage and released at schizont rupture. The response of V gamma 9+ T cells to parasite components is inhibited by antibodies to major histocompatibility complex (MHC) class I and class II. However, the inhibition by anti-MHC class II antibodies can be overcome by the addition of interleukin-2 (IL-2) to the cultures, suggesting that gamma delta T cells themselves do not recognize MHC class II molecules but require an MHC class II-dependent response taking place in the culture. In contrast, the inhibition by anti-class I antibodies cannot be reversed by addition of IL-2. Since an accompanying CD4+ T-cell response occurred in peripheral blood mononuclear cells cultured with P falciparum antigens, it was considered that these cells provide the cytokines necessary for the subsequent activation and expansion of V gamma 9+ T cells recognizing components of the parasite and MHC class I molecules. This was confirmed by reconstituting the response of enriched gamma delta T cells to P falciparum schizont extract by addition of purified CD4+ T cells.
Jones
S M
SM
Department of Biology, Imperial College of Science, Technology and Medicine, London, UK.
Goodier
M R
MR
Langhorne
J
J
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018929:Cell Culture Techniques; D004306:Dose-Response Relationship, Immunologic; D006681:HLA-D Antigens / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*
D000953:Antigens, Protozoan; D006681:HLA-D Antigens; D015395:Histocompatibility Antigens Class I; D007376:Interleukin-2; D016692:Receptors, Antigen, T-Cell, gamma-delta