Antibodies to Transforming Growth Factor-beta 2 Peptides: Specific Detection of TGF-beta 2 in Immunoassays

Polyclonal antibodies have been raised to synthetic peptides corresponding to several regions of transforming growth factor-beta 2 (TGF-beta). All antisera were tested for their ability to react with either the native or reduced forms of both TGF-beta 1 and TGF-beta 2 in enzyme linked immunosorbent assays, Western blots, and immunoprecipitation assays. On Western blots, antisera raised to a peptide corresponding to residues 50-75 of TGF-beta 2 specifically detected 5 ng TGF-beta 2, while antisera raised to regions 1-30 and 79-108 cross-reacted with TGF-beta 1 Anti-P 50-75(2) also localized TGF-beta 2 in murine placenta in immunohistochemical studies. In immunoprecipitation assays with either iodinated TGF-beta s or with media conditioned by cells labeled with [S-35]cysteine, both anti-P 50-75(2) and anti-P 79-108(2) specifically immunoprecipitated TGF-beta 2 under reducing conditions only, while anti-P 79-108(2) also reacted with TGF-beta 1. None of the TGF-beta 2 peptide antibodies was able to block receptor binding of either TGF-fil or 2. Analysis of the cross-reactivity patterns of these peptide antibodies suggests conformational differences between TGF-beta 1 and TGF-beta 2.