How learning shapes immunity

Experimental studies in rodents and humans have convincingly demonstrated that immune functions can be modulated by associative learning processes. We have established a conditioned taste avoidance (CTA) paradigm in rats by pairing a novel taste (conditioned stimulus, CS) with an injection of the immunosuppressive drug cyclosporine A (CsA; unconditioned stimulus, US). Re-exposure to the CS results in a pronounced CTA and, more importantly, in a selective suppression of specific T-cell functions, mimicking the drugs’ effects. To provide a basis for using learned immunosuppressive strategies in clinical situations, we are currently investigating the neurobiological mechanisms underlying the extinction of conditioned immunosuppressive responses and the generalizability of our findings to other immunomodulatory drugs.