Measurement of human latent transforming growth factor-β1 using a latency associated protein-reactive ELISA

► Monoclonal antibodies were made against the LAP entity in human latent TGF-β1. ► A LAP ELISA specific for human latent TGF-β1, but not -β2 or -β3, was developed. ► The LAP ELISA quantified latent TGF-β1 in human samples without acid treatment. ► LAP ELISA analysis correlated with total TGF-β1 measurement by TGF-β1 ELISA. ► Bovine serum in human cell supernatants did not interfere with the LAP ELISA analysis.