A Novel Agonist Anti-Human OX40L Monoclonal Antibody That Stimulates T Cell Proliferation and Enhances Cytokine Secretion

Abstract

OX40L (CD252), a membrane-bound member of the tumor necrosis factor superfamily, is known to be a critical co-stimulatory molecule during immune response. Here, we describe an agonistic mouse anti-human OX40L monoclonal antibody (clone 1E7) recognizing a novel epitope of OX40L antigen. Using this antibody, we found that OX40L was transiently upregulated on CD4⁺ T cells during the early stage of activation. Cross-linking of OX40L with monoclonal antibody 1E7 markedly promoted T cell proliferation and activation and enhanced cytokine production, demonstrating that OX40L transmitted a signal to T cells. Thus, OX40L may play an important role in the early phase of T cell activation and proliferation.