Activation of T cells is known to be modulated by positive or negative co-signaling molecules. The B7-family of costimulatory molecules has received the greatest attention in the past, and intervention in B7-family signaling pathways has proven to be an efficacious strategy for treating autoimmune diseases in the clinic. In recent months a new family of molecules has garnered interest -- the butyrophilins -- and early data is suggesting that these butyrophilin and butyrophilin- like molecules have the potential for influencing the nature of immune and inflammatory responses. In vitro studies have revealed that butyrophilins, such as butyrophilin-like 2 (BTNL2), can negatively regulate T cell proliferation and cytokine production. Additionally, genetic studies have described polymorphisms in BTNL2 which are reported to be associated with disorders such as sarcoidosis, myositis and ulcerative colitis. The potential for interdicting the butyrophilin pathways highlights potential opportunities for developing new therapeutic strategies for treating autoimmune and inflammatory disorders. This review will focus on the emerging information of this new class of regulatory molecules.
Keywords: Immunomodulation, B7 family, butyrophilin, lymphocytes, costimulation, BTNL2, CTLA4