Lack of Specificity of Commercial Antibodies Leads to Misidentification of Angiotensin Type-1 Receptor Protein
To the Editor:
We agree with the report by Herrera et al1 demonstrating that antiangiotensin II type-1 receptor (AT1R) antibodies that are commonly used exhibit nonspecific binding that may lead to erroneous results. Because only 3 AT1R antibodies were used in the study, we would like to share our findings to support their conclusion.
Antihemagglutinin antibody detected a major band (≈40 kDa) in human embryonic kidney cells expressing rat AT1AR fused with hemagglutinin tag at either amino terminus or carboxyl terminus but not in the control cells. The molecular weight is consistent with the AT1AR band observed by Herrera et al.1 In contrast, no specific difference was observed among the cell lysates immunoblotted with 3 distinct AT1R antibodies, which should have detected rat AT1AR according to the manufacturers (Figure).
Herrera et al1 used mouse tissues and cells expressing mouse AT1AR for their experiments. Our data support and expand the findings by including rat AT1AR and adding 2 other frequently used AT1R antibodies. Researchers must be aware that commercially available AT1R antibodies and antibodies against other G protein–coupled receptors may not be specific enough to quantify the receptor expression. To publish an article using an AT1R antibody, it should be accompanied by sufficient evidence to support the specificity. We also encourage the antibody manufacturers to include rigorous confirmation before commercialization.
Katherine J. Elliott
Cardiovascular Research Center
Temple University School of Medicine
Sources of Funding
This work was supported by National Institutes of Health grant HL076770.
Letters to the Editor will be published, if suitable, as space permits. They should not exceed 500 words (typed double-spaced) plus 5 references in length and may be subject to editing or abridgment.
- © 2013 American Heart Association, Inc.