Thymopentin is a synthetic, immunomodulatory pentapeptide (thymopoietin, 32-36). In animal models of experimental autoimmune encephalitis (EAE), thymopentin decreases phosphorylation of IκB kinase and inhibits production of HSP72, lessening disease severity. In other models, thymopentin decreases iNOS expression and activity, exhibiting potential anticancer chemotherapeutic benefit in the treatment of Sezary syndrome. In macrophages, this compound increases activation of NF-κB. In other in vitro models, thymopentin binds to MHC II HLA-DR complexes and modulates T cell activity.