Response to lack of specificity of commercial antibodies leads to misidentification of angiotensin type-1 receptor protein.

Response to Lack of Specificity of Commercial Antibodies Leads to Misidentification of Angiotensin Type-1 Receptor Protein We read with great interest the letter from Eguchi et al1 providing additional evidence to support the lack of suitability of commercial antibodies for detecting angiotensin type-1 (AT1) receptor protein in experimental systems. The data from Eguchi and associates extend our previous report2 by documenting the failure of 2 additional antibodies to specifically detect rat AT1 receptor protein in Western blots of protein isolated from cells transfected with rat AT1 receptors fused with a hemagglutinin tag. Including Eguchi’s letter and our study, there are now independent publications from 4 different laboratories demonstrating lack of specificity of 7 commonly used anti-AT1 receptor antibodies available from reputable commercial sources1–4 (Table). Indeed, it is notable that none of the antibodies tested have demonstrated specificity for AT1 receptor protein. Thus, it is incumbent on investigators to verify the specificity and suitability of antiAT1 receptor antibodies for their particular experimental application. Reviewers and journals should likewise require such verification.