INDIVIDUAL-DIFFERENCES IN PERIPHERAL-BLOOD IMMUNOLOGICAL AND HORMONALMEASURES IN ADULT MALE RHESUS MACAQUES (MACACA-MULATTA) - EVIDENCE FOR TEMPORAL AND SITUATIONAL CONSISTENCY

A growing body of research has indicated that consistent individual di fferences exist in physiological systems with which the immune system interacts. Few data have been reported that demonstrate stable individ ual differences in immunological measures, however. In the present stu dy, enumerative measures of immune system activity were examined in 36 adult male rhesus macaques over a 13 month period under baseline cond itions as well as under conditions of pharmacological and physical cha llenge. Blood samples were assayed for plasma concentrations of ACTH a nd cortisol, as well as neutrophil, total lymphocyte, CD4+ and CD8+ ly mphocyte numbers, and the CD4/CD8 ratio. Analyses revealed that indivi dual differences in the CD4/CD8 ratio and, to a lesser extent, plasma ACTH and cortisol concentrations, and neutrophil and CD4+ lymphocyte n umbers were consistent across situations and times, despite changes in mean values during the various blood sampling sessions. The results s uggest that the CD4/CD8 ratio might be considered trait-like and a use ful immunological measure of biobehavioral organization. (C) 1998 Wile y-Liss, Inc.