Anti-mouse OX40 (CD134)-InVivo (Clone: OX-86) monoclonal antibody reacts with mouse OX-40 also known as CD134. OX-40 plays a major role in regulating both CD4 and CD8 T cell clonal expansion. Anti-mouse OX40 (CD134)-InVivo treatment strongly enhances the generation of antigen-specific effector T cells, prevents the induction of T cell tolerance, and delays tumor growth in vivo.