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.
MacLeod
Megan
M
Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3JT, UK.
Kwakkenbos
Mark J
MJ
Crawford
Alison
A
Brown
Sheila
S
Stockinger
Brigitta
B
Schepers
Koen
K
Schumacher
Ton
T
Gray
David
D
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