Development of a sandwich ELISA for evaluating soluble OX40L (CD252) in human sera of different ages or with Graves' disease.
ABSTRACT OX40 ligand (CD252), a molecule originally identified as human gp34, is an important costimulatory molecule during immune response. Here, we describe a sandwich ELISA for the detection and quantification of soluble OX40L using anti-OX40L monoclonal antibodies 1G1 and 4C12 as capture and detecting antibody, respectively. With this ELISA, the existence and concentration of soluble forms of OX40L (sOX40L) was demonstrated for the first time. It was found that soluble OX40L is detectable in the sera of elderly persons (above 60 years old) and patients with Graves' disease which has the highest mean serum concentration of sOX40L, suggesting the potential diagnostic significance of sOX40L in the disease. Surprisingly, the quantitation of sOX40L was correlated with the age and among these subjects, those of 70s and 80s have much higher sOX40L concentration than those of 60s.