Description: The ACT35 monoclonal antibody reacts with human CD134, also known as OX-40. A member of the TNF receptor superfamily, CD134/OX-40 is a 50 kDa type I membrane glycoprotein expressed by activated T lymphocytes. The interaction of CD134 with OX-40L has been implicated in T cell-dependent humoral response, regulation of primary T cell expansion, survival of T cells, size of the memory T cell pool and regulation of tolerance in the CD4+ T cell compartment.