Age-related changes in the subsets and functions of human T lymphocytes
Kishimoto, S.; Tomino, S.; Inomata, K.; Kotegawa, S.; Saito, T.; Kuroki, M.; Mitsuya, H.; Hisamitsu, S.
Journal of Immunology 121(5): 1773-1780
1978
ISSN/ISBN: 0022-1767 PMID: 309481 Document Number: 127389
Changes in immunocompetence associated with aging were studied in humans by the use of various immunologic parameters. Volunteers examined in this study were apparently healthy without diseases affecting the immune system and ranged from 14-89 yr of age. The absolute number of peripheral blood lymphocytes (PBL) decreased with aging. The mean count was 2043 in the adult group (over 60 years of age). When T and concanavalin A was impaired in the aged (aged 70-83 years) compared to the young adult group (aged 20-40 years) (P < 0.01), whereas the response to pokeweed mitogen (PWM) was of the same magnitude. PHA response was negatively correlated with the proportion of IgG-Fc receptor-bearing T cells. The mixed lymphocyte culture reaction with mitomycin-treated AL1 cells derived from Burkitt's lymphoma was impaired in the aged group (P < 0.01) as was cell-mediated cytotoxicity to AL1 cells as target cells (P < 0.05). Levels of IgG and IgA in plasma were significantly higher in the aged than in the adult group (P < 0.001), whereas those of IgM and IgE were not different. Radioimmunoassay determination of Ig classes revealed that the geometric means of IgG, but not IgM or IgA, synthesized in vitro was significantly increased in the aged compared to the young adult group (P < 0.05) when PBL were cultured in the presence of PWM for 7 days. This increase in IgG synthesis in the aged group was attributed to enhanced T helper activity.