Sociability influences interferon-gamma secretion and glucocorticoid sensitivity in adult male rhesus macaques |
N. Maninger1,2, J. P. Capitanio1,2 and C. M. Brennan2
1Psychology Department, University of California, One Shields Ave, Davis, CA 95616, USA, 2California National Primate Research Center, Davis, CA |
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| The personality dimension Sociability has been found to influence immune responses. Using a prospective design, we examined whether variation in Sociability (high vs. low) in adult male rhesus macaques (Macaca mulatta, N = 36) was related to production of interferon (IFN)-gamma (a pro-inflammatory cytokine involved in cell-mediated immunity). Subjects were inoculated with either simian immunodeficiency virus (SIV, n = 24) or saline (n = 12), and socialized daily for 100 minutes in 2-4 member social groups. Blood samples were obtained pre-inoculation, 5 weeks post-inoculation (p.i.), and every 4 weeks thereafter. Whole blood was incubated with either staphylococcal enterotoxin B (SEB) alone or SEB and the synthetic glucocorticoid dexamethasone for 24 hours, and supernatant was extracted for later assay. Concentrations of IFN-gamma were determined by ELISA for pre-inoculation, weeks 5 and 9 p.i., and at the end of disease for SIV-inoculated animals, and corresponding time points for controls. ANOVA analysis revealed no differences between high and low Sociable animals in SEB-stimulated IFN-gamma at pre-inoculation (P > 0.05). Incubation with dexamethasone resulted in decreases in IFN-gamma in a dose-dependent fashion. At lower concentrations of dexamethasone, high Sociable subjects had a greater decrease in IFN-gamma than low Sociable animals before inoculation. After SIV inoculation, high Sociable subjects had higher IFN-gamma than low Sociable animals. These data suggest that high Sociable animals have higher glucocorticoid sensitivity, and are consistent with other data suggesting greater immunological responsiveness. |
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