Conditioned enhancement of antibody production using antigen as the unconditioned stimulus.

Antigen is the most salient stimulus for an unconditional activation of the immune system. BALB/c mice were given repeated immunizations with keyhole limpet hemocyanin (KLH) paired with a gustatory conditioned stimulus (CS). A classically conditioned enhancement of anti-KLH antibody titers was observed when conditioned mice were reexposed to the CS in the context of reexposure to a minimally immunogenic dose of that same antigen. An interaction between signals derived from the neuroendocrine and immune systems is hypothesized to mediate this conditioned immune response.