Sandwich enzyme-linked immunosorbent assays (SELISAs) quantitate and distinguish two forms of transforming growth factor-beta (TGF-beta 1 and TGF-beta 2) in complex biological fluids.

We have developed sandwich enzyme-linked immunosorbent assays (SELISAs) for TGF-beta 1 and TGF-beta 2 using both turkey and rabbit neutralizing polyclonal antibodies against native TGF-beta s. Each assay is based on the binding of two different antibodies to distinct epitopes of a single TGF-beta molecule. With these assays, TGF-beta types 1 and 2 can each be specifically quantitated in complex biological fluids, with detection limits of 2-5 pg. TGF-beta 3 and TGF-beta 5 either do not cross-react or cross-react very poorly in these assays. TGF-beta 1.2 heterodimer, although 50-80% neutralized by either TGF-beta 1 or TGF-beta 2 antibodies, shows only a 1.5 and 3.7% cross-reactivity in the TGF-beta 1 and TGF-beta 2 SELISAs, respectively. The SELISAs reported here represent the most specific, rapid, and precise assays for TGF-beta 1 and TGF-beta 2 reported thus far.