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Developmental Immunology
Volume 3, Issue 1, Pages 25-34
http://dx.doi.org/10.1155/1992/31573

The Acquisition of a Memory Phenotype by Murine CD4+ T Cells Is Accompanied by a Loss in Their Capacity to Increase Intracellular Calcium

Section of Immunology, TNO Institute of Aging and Vascular Research TNO, P.O. Box 430, Leiden 2300 AK, The Netherlands

Received 2 April 1992; Accepted 23 June 1992

Copyright © 1992 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

During the process of aging, the fraction of CD4+ T Cells with a naive phenotype, that is, Pgp-1- CD45RBHighMEL-14+, decreases in favor of CD4+ T memory cells. Total CD4+ T cells from aged mice displayed a diminished calcium response to anti-CD3 and even ionomycin as compared to the cells from young mice, and this was related to the changed composition of the CD4+ T-cell population. Regardless the age of the donor mice, naive CD4+ T cells effectively increased intracellular calcium, whereas memory CD4+ T cells were impaired in this regard. In addition, a heterogeneity in the differentiation stage of the naive CD4+ T cells was shown by the observation that calcium mobilization in naive CD4+ T cells from young mice was more profound than that in their aged counterparts. These data thus indicate that during the acquisition of a memory phenotype, murine CD4+ T cells lose the capacity to increase intracellular calcium, which in turn may be responsible for the decreased level of IL-2 production by these cells.