title: Influence of age on the ability of thymic adherent cells to produce factors in vitro which modulate immune responses of thymocytes.
abstract: Thymic adherent cells from BALB/c mice ranging in age from 1 day to 20 months were cultured in vitro for 1 month. The supernatants, collected at weekly intervals, were assessed for their ability to augment the antigen/mitogen responses of thymocytes from 2- or 4-week-old BALB/c mice and spleen cells from 3-month-old nude BALB/c mice. The results indicate that (a) the ability of thymic adherent cells to produce an augmenting factor(s) declines sharply between 2.5 and 5 months of age; (b) thymic adherent cells of 1-day-old mice synthesize an inhibitory factor(s) in addition to the augmenting factor, while those of young adult mice synthesize only the augmenting factor, and those of 20-month-old mice synthesize primarily the inhibitory factor; (c) supernatants containing the augmenting factor can be neutralized by mixing them with supernatants containing the inhibitory factor; (d) thymocytes which are responsive to the augmenting factor are immature as judged by their sensitivity to dexamethasone and by their ability to bind macrophages; and (e) spleen cells of normal and nude mice are not responsive to either the augmenting or the inhibitory factor of the supernatant.
mesh_terms: D000375:Aging; D000818:Animals; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
chemical_list: D007376:Interleukin-2; D008222:Lymphokines