V beta gene repertoires in aging mice.
To determine whether aging and thymic involution are associated with defects in intrathymic T cell selection or clonal instabilities, we compared transcript levels for 18 V beta genes in thymic and splenic T cells of young (2 month), adult (12 month), and old (20 month) mice of various Mls and MHC haplotypes (C57BL/6, BALB/c, and DBA/2). The results showed that the unselected thymic V beta repertoires remain stable throughout life, despite severe reduction in cellularity in the thymus of aged mice. Similarly, splenic CD4 and CD8 V beta repertoires showed no significant alterations, and no leakage to the periphery of endogenous superantigen-reactive V beta clones was observed with age, even in irradiated and bone marrow-reconstituted old mice. Responses in vitro to bacterial superantigens were undiminished with age but, significantly, some of these superantigens expanded V beta clones that are cross-reactive with endogenous superantigens and are normally partially (V beta 11 and -12) or severely (V beta 3.1) deleted in BALB/c mice. In the course of these studies, several previously unrecognized reactivities of V beta with staphylococcal toxins were also revealed.
González-Quintial
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Department of Immunology, Scripps Research Institute, La Jolla, CA 92037.
Theofilopoulos
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D000375:Aging; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D001427:Bacterial Toxins / Q000276:immunology; D016026:Bone Marrow Transplantation; D002999:Clone Cells; D004768:Enterotoxins / Q000276:immunology; D015870:Gene Expression; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D008285:Major Histocompatibility Complex; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000235:genetics; D011828:Radiation Chimera; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D013154:Spleen / Q000166:cytology; D016176:T-Lymphocyte Subsets / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology
D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D004768:Enterotoxins; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; C026066:enterotoxin A, Staphylococcal