Senescence of the immune system.
D000328:Adult; D000368:Aged; D000375:Aging; D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D002455:Cell Division; D006087:Graft vs Host Reaction; D006801:Humans; D007109:Immunity; D007111:Immunity, Cellular; D007376:Interleukin-2; D051379:Mice; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology / Q000502:physiology
D007376:Interleukin-2