Recent immune status determines the source of antigens that drive homeostatic T cell expansion.
Homeostatic proliferation of naive T cells transferred to T cell-deficient syngeneic mice is driven by low-affinity self-MHC/peptide ligands and the cytokine IL-7. In addition to homeostatic proliferation, a subset of naive T cells undergoes massive proliferation in chronically immunodeficient hosts, but not in irradiated normal hosts. Such rapid T cell proliferation occurs largely independent of homeostatic factors, because it was apparent in the absence of IL-7 and in T cell-sufficient hosts devoid of functional T cell immunity. Strikingly, immunodeficient mice raised under germfree conditions supported only slow homeostatic proliferation, but not the marked T cell proliferation observed in conventionally raised immunodeficient mice. Thus, polyclonal naive T cell expansion in T cell-deficient hosts can be driven predominantly by either self-Ags or foreign Ags depending on the host's previous state of T cell immunocompetency.
Kieper
William C
WC
Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Troy
Amy
A
Burghardt
J Theodore
JT
Ramsey
Chris
C
Lee
Joon Youb
JY
Jiang
Han-Qing
HQ
Dummer
Wolfgang
W
Shen
Hao
H
Cebra
John J
JJ
Surh
Charles D
CD
D000818:Animals; D000941:Antigens / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology; D049109:Cell Proliferation; D016654:Genes, RAG-1; D006706:Homeostasis; D007153:Immunologic Deficiency Syndromes / Q000276:immunology / Q000473:pathology; D015851:Interleukin-7 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016513:Mice, SCID; D008822:Mice, Transgenic; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*
D000941:Antigens; D015851:Interleukin-7