Specificity of Antibodies Against Rodent Transforming Growth Factor-α Protein

We found that the immunohistochemical distribution of TGF-α varied in rodent tissues depending on the antibody used, suggesting that the specificity of anti-TGF-α antibodies differs significantly. To address this issue, we compared the specificity of two representative antibodies that have been widely used to detect rodent TGF-α. In a competition study, the antibodies were preincubated with an excess of synthetic rat TGF-α34-50 and were used for staining of rat and mouse kidneys and/or uterus. The results revealed that one of the antibodies, anti-rat TGF-α polyclonal antibody, was neutralized by the peptide, whereas the other, anti-human TGF-α monoclonal antibody, was not absorbed by the peptide up to an excess of 100-fold. Western blotting analysis showed that the anti-rat TGF-α polyclonal antibody recognized both human and rat purified TGF-α. However, the anti-human TGF-α monoclonal antibody did not detect purified rat TGF-α, although the antibody reacted with mouse proteins other than TGF-α from kidneys and uterus, purified human TGF-α, and mouse carbonic anhydrase II. These data indicate that the anti-human TGF-α monoclonal antibody does not recognize rodent TGF-α under our experimental conditions and suggest that distribution of TGF-α in rodent tissues may need to be reexamined.