Psychosocial Factors and Immune Senescence in the Aged Primatea

Abstract

With increasing age, old animals and humans show decreases in a number of immune responses indicative of the process of immune senescence. Our studies investigated whether social companionship, as a potentially positive psychological intervention, would increase lymphocyte proliferation and natural killer cell activity in the aged nonhuman primate. Contrary to our initial hypothesis, social stimulation resulted in decreased immune responses in old monkeys. With specific modifications of the housing conditions it was possible to prevent these decreases in immune responses from occurring, but social companionship still failed to enhance immune responses in the aged monkey.

Psychosocial factors and immunity in nonhuman primates: a review.

“…Moreover, the low immune responses in aged female rhesus monkeys were reduced further by relatively minor changes in their social environment. For example, the addition of a single juvenile monkey into the cage of an aged monkey resulted in a significant decline in both lymphocyte proliferation and cytotoxic responses (38). Changes occurred rapidly, within a day, and in one experiment were sustained for 3 months ( Figure 7).…”

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

“…o lY95 it1c. Aging in humans, primates and rodents is accompanied by a reduction in lymphocyte proliferative response to mitogens (Staiano-Coico et al, 1984;Kubbies et al, 1985;Hausman and Wechsler, 1985;Miller, 1986;Grossman et al, 1989;Eylar et al, 198811989;1989a,b;Coe et al, 1992;Erschler et al, 1988). It has been shown in mice that decreased intracellular free calcium ([Ca2 1,) responses are correlated with the decrease in lymphocyte proliferation occurring with age (Philosophe and Miller, 1989 j. Stimulation with anti-CD3 mAb transduces a signal through the TCRICD3 complex, resulting in activation of the IP3 pathway and transient increases in ICa2+l,.…”

Contributions of Nonhuman Primates to Research on Aging

“…Comparison between the 2 housing conditions thus enables evaluation of environmental influences on restorative homeostatic mechanisms during aging. 43,45,101 …”

“…101 Reduced psychosocial stress during aging, however, was reported in rhesus macaques and Japanese macaques living in colonies where strong intergenerational relationships developed among females to presumably provide mutual support in conflicts with nonfamilial members. 2,45,147 …”

“…Comparison between the 2 housing conditions thus enables evaluation of environmental influences on restorative homeostatic mechanisms during aging. 43,45,101 Social rank among aging females constitutes an important measure for relating psychosocial stress to aging that may be comparable to socioeconomic pressures and effects on quality of life in aging humans. 2,101 Female social dominance ranking is inherited, and female rhesus macaques born to low-ranking females tend to remain at lower social status.…”