title: Immunological studies of aging. Decreased production of and response to T cell growth factor by lymphocytes from aged humans.
abstract: Human lymphocytes from elderly and young donors were cultured with phytohemagglutinin (PHA) or concanavalin A. Cultures from old donors produced less T cell growth factor (TCGF) and incorporated less tritiated thymidine (3H-Tdr) than did similar cultures from young donors in the presence of either mitogen. Furthermore, the response of lymphocytes from elderly donors to TCGF was impaired. Thus, PHA-activated T cells from aged donors showed no increase tritiated thymidine incorporation when incubated with exogenous human TCGF. In contrast, addition of exogenous human TCGF to PHA-activated peripheral blood leukocytes from younger individuals increased tritiated thymidine incorporation by 30-50%. The impaired response to TCGF was associated with decreased binding of TCGF by PHA-activated cells from old donors. TCGF production or responsiveness was not associated with the presence of "suppressor" activity in elderly T cell preparations. These studies suggest a possible molecular mechanism for the impaired proliferative response of elderly human T cells. These data lend support to the hypothesis that defects in the capacity to either produce or respond to TCGF may be a fundamental cause of immune deficiency.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D002455:Cell Division; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology*; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D008222:Lymphokines / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology
chemical_list: D007376:Interleukin-2; D008222:Lymphokines; D010835:Phytohemagglutinins; D003208:Concanavalin A