Alterations in the Kinetics of CD4+ T Cell Responses with Aging / 대한류마티스학회지

ABSTRACT

OBJECTIVE: Alterations in the immune system occur with aging, and these contribute to an increased risk of infection and malignancy. The age-associated changes in T cell immunity range from single cell function to the maintenance of cell populations. We investigated the kinetics of CD4+ T cell activation and proliferation in young and elderly subjects after stimulating their peripheral blood mononuclear cells with anti-CD3 and anti-CD28 antibodies (Abs). METHODS: The expressions of the activation markers CD69, CD40L and CD25 on the CD4+ T cells from young (n=14) and elderly (n=19) were analyzed at 6, 24 and 48 hours (hrs) of T cell receptor (TCR) stimulation by using flow cytometry. In the same individuals, the CD4+ T cell proliferation was determined at 48 and 96 hrs of TCR stimulation by using the CFSE dilution method. RESULTS: The elderly had decreased CD69 and CD40L expressions on the CD4+ T cells at 6 hrs of stimulation, as compared to that of the young patients. The elderly also had a decreased CD25 expression on the CD4+ T cells at 24 hrs of stimulation. However, the two groups had similar levels of the CD25, CD69 and CD40L expressions at 48 hrs of stimulation. The elderly had decreased CD4+ T cell proliferation at 96 hrs of stimulation, as compared to that of the young, although both groups had similar levels of CD4+ T cell proliferation at 48 hrs of stimulation. CONCLUSION: Our findings suggest that the elderly have altered kinetics of CD4+ T cell activation and proliferation in response to anti-CD3 and -CD28 Ab stimulation, and that such an altered response is governed by the duration of stimulation.