Influence of age, sex, and dietary restriction on intracellular free calcium responses of CD4 + lymphocytes in rhesus monkeys ( Macaca mulatta )

The influence of aging and dietary restriction on increase in intracellular free calcium ([Ca 2+ ] i ) of CD4 + lymphocytes from Macaca mulatta was examined after stimulation with anti‐CD3 mAb. We used a flow cytometric assay with the dye indo‐1 and either direct or reciprocal immunofluorescent staining to dientify CD4 + cells. After stimulation with anti‐CD3 mAb, intracellular free calcium responses were reduced in CD4 + lymphocytes from old male and female ad libitum fed monkeys compared to young and adult male or female monkeys. Old female monkeys had significantly lower [Ca 2+ ] i than did old male monkeys. The reduced responses were in part related to a decreased percentage of responding cells. Dietary restrition of males over a four‐year period did not alter [Ca 2+ ] i response compared to ad libitum fed male monkeys. Female monkeys of all ages (which were restricted only for four months) also had similar [Ca 2+ ] i responses to ad libitum fed controls. Our data suggest that age‐related changes in [Ca 2+ ] i responses are similar between humans and M. mulatta , and that over these intervals, no effects of caloric restrictions can be detected. © 1995 Wiley‐Liss, Inc.