Development of antibodies for studying conceptus interferons in the cow

Three synthetic peptides comprising amino acids 100-113, 131-140 and 152-172 of bovine trophoblast protein-1 (bTP-1) were synthesized, coupled to keyhole limpet hemocyanin and used for antibody production in rabbits. Of the resultant anti-peptide antibodies, the antibody directed towards the C-terminal of bTP-1 (152-172) was found effective for recognizing native bTP-1 in enzyme-linked immunoabsorbent assay (ELISA), Western blotting and immunocytochemistry systems. By immunocytochemistry, anti-bTP-1(152-172) reacted with kidney and lung tissue, suggesting that the presence of other interferons in extra-embryonic tissues limits the specificity of the antibody. The other two anti-peptide antibodies showed low cross-reactivity to native bTP-1. None of the three peptides displayed antiviral activity or inhibited antiviral activity of bovine conceptus-conditioned culture medium. Of other anti-interferon antibodies tested, antiserum to human interferon-alpha and bovine interferon-alpha I 1 showed only slight cross-reactivity with bTP-1 and trophoblast protein-1 (oTP-1). A monoclonal antibody raised against oTP-1 also recognized bTP-1 and bTP-1(152-172), suggesting that it recognizes an epitope on the C-terminal region of oTP-1 and bTP-1. In summary, the C-terminal region of bTP-1 is antigenic and accessible to antibodies. Thus, antibodies directed against this region should prove useful for immunochemical studies of bTP-1.