Cutting Edge: Limiting amounts of IL-7 do not control contraction of CD4+ T cell responses.
During the acute T cell response most effector T cells die while some survive and become memory T cells. Selective expression of CD127 (IL-7Ralpha) on effector T cells has been proposed to engender their survival into the memory pool. We assessed the role of IL-7 in effector T cell survival using MHC class II tetramers to track a CD4+ T cell response following infection with a recombinant vaccinia virus (rVV-2W1S). Exogenous IL-7 prevented the contraction of the 2W1S-specific CD4+ T cell response after rVV-2W1S infection. IL-7 increased proliferation of, and Bcl-2 expression within, 2W1S-specific T cells; the latter was required for IL-7-driven prevention of contraction. Conversely, in vivo neutralization of IL-7 or Bcl-2 did not exacerbate the contraction of 2W1S-specific CD4+ T cells. These data suggest that IL-7 administration may enhance the survival of effector T cells but that IL-7 is not the limiting factor during normal contraction of the response.
Tripathi
Pulak
P
Department of Pediatrics, Division of Immunobiology, Children's Hospital Medical Center, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
Mitchell
Thomas C
TC
Finkelman
Fred
F
Hildeman
David A
DA
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000821:virology; D049109:Cell Proliferation; D002470:Cell Survival; D015851:Interleukin-7 / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D014616:Vaccinia virus
D015851:Interleukin-7; D019253:Proto-Oncogene Proteins c-bcl-2