Behaviorally Conditioned Immunosuppression

TLDR

The study conditioned rats to develop a taste aversion by pairing saccharin with cyclophosphamide or LiCl, then challenged them with sheep erythrocytes to assess immune response. Cyclophosphamide-conditioned rats showed complete suppression of hemagglutinating antibody titers when antigen was administered with cyclophosphamide or after saccharin exposure, whereas LiCl conditioning had no effect on antibody production.

Abstract

An illness-induced taste aversion was conditioned in rats by pairing saccharin with cyclophosphamide, an immunosuppressive agent. Three days after conditioning, all animals were injected with sheep erythrocytes. Hemagglutinating antibody titers measured 6 days after antigen administration were high in placebo-treated rats. High titers were also observed in nonconditioned animals and in conditioned animals that were nor subsequently exposed to saccharin. No agglutinating antibody was detected in conditioned animals treated with cyclophosphamide at the time of antigen administration. Conditioned animals exposed to saccharin at the time of or following the injection of antigen were significantly immunosuppressed. An illness-induced taste aversion was also conditioned using LiCl, a nonimmunosuppressive agent. In this instance, however, there was no attenuation of hemagglutinating antibody titers in response to injection with antigen.