Blocking T cell co-stimulation using a CD80 blocking small molecule reduces delayed type hypersensitivity responses in rhesus monkeys

Abstract

Blockade of co-stimulation signals between T cells and antigen-presenting cells could be an important approach for treatment of autoimmune diseases and transplant rejection. Recently a series of small compound inhibitors which bind human CD80 (B7-1) and inhibit T cell co-stimulation has been described. To investigate their potency for clinical use, one of these compounds, RhuDex™, was evaluated for reactivity with rhesus monkey CD80. The in vitro biological effect on rhesus monkey lymphocytes, the potency for suppression of an inflammatory recall response and the protein-induced delayed type hypersensitivity (DTH) response in the skin were studied. In a rhesus monkey T cell co-stimulation assay RhuDex™ inhibited proinflammatory cytokine release and cellular proliferation with micromolar potency. Systemic administration of RhuDex™ to rhesus monkeys inhibited the DTH response significantly, indicating that this compound may inhibit autoimmune mediated inflammatory processes where the target, CD80, is up-regulated. © 2009 British Society for Immunology.