Sandwich ELISA quantitative detection kit for Human TNFSF4/OX40L in cell culture supernates, serum and plasma (heparin, EDTA).OX40L is the ligand for CD134 and is expressed on such cells as DC2s enabling amplification of Th2 cell differentiation. OX40L has also been designated CD252. By analysis of an interspecific backcross, the mouse Tnfsf4 gene is mapped to chromosome 1. Using fluorescence in situ hybridization, they localized the human TNFSF4 gene to 1q25, a region sharing homology of synteny with the portion of mouse chromosome 1 containing the Tnfsf4 gene. OX40L strongly inhibited the generation of IL-10-producing Tr1 cells induced by two physiologic stimuli, the inducible costimulatory ligand and immature dendritic cells. In addition, OX40L strongly inhibited IL-10 production and suppressive function of differentiated IL-10-producing Tr1 cells. Tnfsf4 underlies Ath1 in mice and that polymorphisms in its human homolog TNFSF4 increase the risk of myocardial infarction in humans.