Antigenic properties of the second loop of transforming growth factor alpha by synthetic peptides

We describe synthesis and immunological properties of peptides constructed based on the second loop of TGF-alpha. The peptides were synthesized manually using a standard solid-phase Boc protocol. Sulfhydryl groups were protected as acetamidomethyl derivatives during the synthesis and the disulfide bridges were formed at high dilution by oxidation with iodine in the presence of glutathione. In ELISA assays antibodies to the peptides were inhibited by the native hormone to various extents. In addition, two peptides reacted well with a polyclonal antibody to TGF-alpha, but this reaction was only slightly inhibited by TGF-alpha in solution.