Psychological Stress, Early Response to Foreign Protein, and Blood Cortisol in Vervets

Abstract

In this study, the focus of attention was the biological response of vervet monkeys (Cercopithecus aethiops) under psychological stress to a well-defined protein, bovine serum albumin, with plasma cortisol as an indicator of alterations in the pituitary-adrenocortical system. The term “psychological” was used simply to indicate that the stress aspects of the experimental situation were considered to have their impact upon the animals primarily by way of the sensory systems, rather than through direct physical or physiological trauma. After immunization, 5 animals were subjected to irregular noise, light, and vertical movement, while 5 controls remained undisturbed except for periodic blood collections. The stress group showed delayed antibody formation, and the antibodies rose to a lower level than in the control group. The serum cortisol values were markedly elevated during the initial period of the experiment in the group exposed to stress.