Abstract # 212:

Scheduled for Saturday, August 20, 2005 10:45 AM-11:00 AM: Session 15 (Parliament Room) Oral Presentation

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
     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.