CD4 memory T cells survive and proliferate but fail to differentiate in the absence of CD40.
Secondary T cell responses are enhanced because of an expansion in numbers of antigen-specific (memory) cells. Using major histocompatibility complex class II tetramers we have tracked peptide-specific endogenous (non-T cell receptor transgenic) CD4 memory T cells in normal and in costimulation-deficient mice. CD4 memory T cells were detectable after immunization for more than 200 days, although decay was apparent. Memory cells generated in CD40 knockout mice by immunization with peptide-pulsed wild-type dendritic cells survived in the absence of CD40 and proliferated when boosted with peptide (plus adjuvant) in a CD40-independent fashion. However, differentiation of the memory cells into cytokine-producing effector cells did not occur in the absence of CD40. The data indicate that memory cells can be generated without passing through the effector cell stage.
Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3JT, UK.
Megan
M
MacLeod
Mark J
MJ
Kwakkenbos
Alison
A
Crawford
Sheila
S
Brown
Brigitta
B
Stockinger
Koen
K
Schepers
Ton
T
Schumacher
David
D
Gray
D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D019013:CD40 Antigens / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation / Q000276:immunology; D049109:Cell Proliferation; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology; D007156:Immunologic Memory; D016130:Immunophenotyping; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data
D019013:CD40 Antigens