Defect of autologous mixed lymphocyte reaction and interleukin-2 in aged individuals.
The proliferative responsiveness of T cells of aged individuals is known to be depressed in both autologous mixed lymphocyte reaction (AMLR) and in PHA-stimulated cultures. In the present study we confirm previous results and also report decreased IL-2 and normal IFN-gamma production (PHA-induced) in aged subjects as compared to young normals. In addition, similar percentages of T lymphocytes expressing surface IL-2 receptors both in the peripheral blood and after different stimulations, i.e. AMLR and PHA, were detected in young and aged individuals. The addition of exogenous IL-2 induces a sharp increase of spontaneous and AMLR proliferation in young individuals, whereas the increase is only slight in aged subjects. The experiments reported herein suggest that in general the T cell proliferation in AMLR is not completely dependent on the presence of IL-2 in the cultures and that aged subjects are probably defective in the production of other factor(s) presumably involved in AMLR proliferation, since the addition of exogenous IL-2 does not produce T-cell proliferation comparable to normal young subjects. The possible meanings of these experimental evidences in AMLR and in the defective immune responses of aged subjects are discussed.
D000328:Adult; D000368:Aged; D000375:Aging; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology*; D007700:Kinetics; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2