Immunosuppressive Action of Heat in Chickens

Abstract

The influence of heat (43-45†) on hemagglutinin production and phagocytosis was evaluated in a strain of New Hampshire chickens. Production of antibody to sheep red blood cells (SRBC) was significantly reduced during the preinduction phase of antibody formation when birds were exposed to 1, 2, 3, or 4 consecutive hours of 30 min of heat within 24 hr of the administration of SRBC. Heat failed to influence hemagglutinin levels when administered 36 hr before the injection of SRBC. Birds exposed to 30 min of heat during the initial 24 hr of the induction phase of antibody formation exhibited a significant reduction in their hemagglutinin titers. Heat treatment did not impair the in vivo clearance of carbon particles.