title: Plaque-forming cell response of human blood lymphocytes. III. Cellular basis of the reduced immune response in the elderly.
abstract: The cellular basis for the reduced immune response of the elderly was studied in vitro. It was found that, with respect to the capacity to respond to relatively T-independent B cell activators by proliferation and generation of plaque-forming cells (PFC), the purified B cell population of aged subjects is relatively intact. Furthermore, macrophages from old and young subjects produce T cell-replacing factors in equivalent amounts. The depressed proliferation and PFC responses to B cell activators in unfractionated lymphocytes from the elderly thus appear to be due to suppressor activity present in a surface Ig-negative cell population, suggesting that alterations in the regulatory (helper and suppressor) functions of T cell populations are the major cause of the reduced humoral immune response associated with aging.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D006462:Hemolytic Plaque Technique; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007111:Immunity, Cellular; D008214:Lymphocytes / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D011817:Rabbits / Q000276:immunology; D013601:T-Lymphocytes / Q000502:physiology
chemical_list: D007106:Immune Sera