Thymic irradiation inhibits the rapid recovery of TH1 but not TH2-like functions of CD4+ T cells after total lymphoid irradiation.
Four to six weeks after total lymphoid irradiation (TLI), there is a selective deficit in the CD4+ T cells which secrete IL-2, proliferate in the MLR, and induce GVHD (Th1-like functions). A similar deficit in CD4+ T cells which secrete IL-4 and help antibody responses (Th2-like functions) is not observed. In the present study, shielding of the thymus with lead during TLI increased the Th1-like functions of CD4+ cells. Mice without thymus shields showed a marked selective reduction in the medullary stromal cells identified with the monoclonal antibody, MD1, and the severe reduction was prevented with thymus shields. Thus, shielding the thymus prevents the depletion of thymic medullary stromal cells and allows for a rapid recovery of Th1-like functions in the mouse spleen after TLI. Th2-like functions recover rapidly after TLI whether or not the thymus is irradiated.
Department of Medicine, Stanford University School of Medicine, California 94305.
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Bass
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Adkins
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Strober
D000818:Animals; D000917:Antibody Formation / Q000528:radiation effects; D015496:CD4-Positive T-Lymphocytes / Q000528:radiation effects*; D006086:Graft vs Host Disease / Q000276:immunology; D007111:Immunity, Cellular / Q000528:radiation effects; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000096:biosynthesis; D007150:Immunohistochemistry; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008211:Lymphocyte Cooperation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008815:Mice, Inbred Strains; D013154:Spleen / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000528:radiation effects*; D013950:Thymus Gland / Q000166:cytology / Q000528:radiation effects*; D014916:Whole-Body Irradiation
D007074:Immunoglobulin G; D007376:Interleukin-2; D015847:Interleukin-4