Effect of age on the human high affinity interleukin 2 receptor of phytohaemagglutinin stimulated peripheral blood lymphocytes.
High affinity interleukin 2 receptors (HA-IL-2R) on mitogen- or antigen-stimulated T cells have been shown to efficiently bind interleukin 2 (IL-2) and to transduce the activation signal(s) that facilitate proliferation. This study was initiated to determine whether the impaired proliferative response of T cells from elderly individuals can be attributed to the defective expression of HA-IL-2R. While cells from both young and old individuals had statistically insignificant differences in the number of HA-IL-2R per membrane IL-2R-positive cell and these receptors displayed similar binding affinities with 125I-IL-2, there were consistently fewer cells and fewer cells expressing HA-IL-2R in the cell cultures from elderly individuals. The magnitude of the age-associated impairment in cell proliferation was decreased, but remained present, when Percoll fractionated lymphoblasts, as compared to peripheral blood lymphocytes (PBL), were cultured in the presence of exogenous interleukin 2 (IL-2). The results demonstrate that a significantly larger percentage of lymphocytes from elderly individuals do not respond to mitogenic stimulation and, probably due to stimulus stress, die in culture. As a consequence there are fewer functionally competent cells expressing the HA-IL-2R in cultures from elderly individuals, which in turn contributes to the age-related defect in the lymphocyte proliferative response.
Nagel
J E
JE
Clinical Immunology Section, National Institute on Aging, Baltimore, MD 21224.
Chopra
R K
RK
Powers
D C
DC
Adler
W H
WH
D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D002455:Cell Division; D002478:Cells, Cultured; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008875:Middle Aged; D010835:Phytohemagglutinins / Q000494:pharmacology*; D015375:Receptors, Interleukin-2 / Q000032:analysis* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D007376:Interleukin-2; D010835:Phytohemagglutinins; D015375:Receptors, Interleukin-2