Differential sensitivity to hibernation of early and late events in development of the immune response.

Abstract

AbstractGround squirrels, Citellus tridecemlineatus, were immunized with a single intraperitoneal injection of sheep red cells four days before, two days before, during and upon arousal from hibernation. The number of antibody‐forming cells per spleen was determined at different times during 56 days of hibernation and during the first week following arousal. All phases of the response, i.e., latent period, proliferative phase, declining phase, were slowed during the hibernation period and we concluded that most of the development occurred during the short periods of spontaneous arousal. The latent period, as compared to the other phases, was the most sensitive to retardation by hibernation. We believe that the resumption of development of the immune response during this phase is relatively delayed upon arousal because the early differentiating cells entered a quiescent state better adapted to hibernation whereas the later cell types did not.