SPECIFICITY OF ANTIBODIES AGAINST RODENT TRANSFORMING GROWTH-FACTOR-ALPHA PROTEIN

We found that the immunohistochemical distribution of TGF-alpha varied in rodent tissues depending on the antibody used, suggesting that the specificity of anti-TCF-alpha antibodies differs significantly. To ad dress this issue, we compared the specificity of two representative an tibodies that have been widely used to detect rodent TGF-alpha. In a c ompetition study, the antibodies were preincubated with an excess of s ynthetic rat TGF-alpha(34-50) and were used for staining of rat and mo use kidneys and/or uterus. The results revealed that one of the antibo dies, anti-rat TGF-alpha polyclonal antibody, was neutralized by the p eptide, whereas the other, anti-human TGF-alpha monoclonal antibody, w as not absorbed by the peptide up to an excess of 100-fold. Western bl otting analysis showed that the anti-rat TGF-alpha polyclonal antibody recognized both human and rat purified TCF-alpha. However, the antihu man TGF-alpha monoclonal antibody did not detect purified rat TGF-alph a, although the antibody reacted with mouse proteins other than TGF-al pha from kidneys and uterus, purified human TGF-alpha, and mouse carbo nic anhydrase II. These data indicate that the anti-human TGF-alpha mo noclonal antibody does not recognize rodent TGF-alpha. under our exper imental conditions and suggest that distribution of TGF-alpha in roden t tissues may need to be reexamined.