Interleukin-1beta mRNA, interleukin-1beta receptor mRNA, and erythropoietin receptor mRNA are expressed in the brain of (CBAxC57Bl)F1 mice. Immunization with sheep erythrocytes stimulated the expression of these cytokines in the cerebral hemispheres. Injection of recombinant erythropoietin reduced expression of interleukin-1beta, interleukin-1beta receptor, and erythropoietin receptor genes in the brain of experimental animals and considerably increased their motor activity in the open field test.