Activation requirements for CD4+ T cells differing in CD45R expression.
Murine CD4+ T cells can be subdivided into naive and memory T cells based on surface phenotype, on recall response to Ag, and on differences in activation requirements. Furthermore, several studies have shown that two signals are required for CD4+ T cell activation; one signal is provided by occupancy of the TCR and the other signal is provided by the APC. In this report, analysis of naive and memory CD4 T cells, separated on the basis of CD45 isoform expression, has shown that their requirements for two signals differ. Activation of memory CD4 T cells to proliferate and secrete IL-2/IL-4 only required occupancy of the TCR complex, whereas activation of naive CD4 T cells required an APC-derived signal as well. Moreover, the signal induced by anti-CD3 antibodies differs from the signal provided by anti-V beta cross-linking of the TCR because both antibodies activate memory CD4 T cells but only anti-CD3 activates naive CD4 T cells. Together these data suggest that the consequence of stimulation through the TCR/CD3 signal complex differs between memory and naive CD4 T cells.
Luqman
M
M
Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06510.
Bottomly
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000502:physiology; D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D017252:CD3 Complex; D015704:CD4 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D006649:Histocompatibility Antigens / Q000032:analysis*; D017493:Leukocyte Common Antigens; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D006649:Histocompatibility Antigens; D011948:Receptors, Antigen, T-Cell; D017493:Leukocyte Common Antigens; D013755:Tetradecanoylphorbol Acetate