The Influence of Hibernation on the Interferon Response in the Spotted Suslik (Spermophilus suslicus)

Abstract

According to the season, the environmental temperature, and their physiological state (whether active or in hibernation), spotted susliks produce different amounts of interferon (IFN) in response to intraperitoneal induction with Newcastle disease virus (NDV). Even though injection of NDV aroused hibernating animals, susliks treated during deep winter hibernation or artificial summer hibernation, or when aroused from winter hibernation, had significantly less IFN in their serum and organs than animals active in summer. Minced tissues taken from such animals and infected with NDV in vitro produced similar relative amounts of IFN. The effects of other environmental factors were studied: IFN productiion in vivo was increased by a high concentration of CO₂ (5%) in the air, but decreased by electric shock stress. A hyporeactive response to IFN induction in vivo was produced in active susliks but not in animals hibernating in summer. These changes in the IFN system associated with season and physiological state cannot be explained merely in terms of the effect of differences in body temperature; they involve also adaptive changes in the animal associated with the onset of hibernation.