A Sensitive Technique for Detecting and Estimating the Peptide Hormone Angiotensin‐II‐β‐amide and its Antibodies by Using Chemically Modified Bacteriophage and Activated Sepharose

Abstract

Angiotensin‐II‐β‐amide was conjugated to bacteriophage T 4 using glutaraldehyde as a cross‐linking agent. The conjugated phage can be inactivated by anti‐angiotensin antibodies and this reaction may be used to detect antibodies at a concentration as low as 100 picograms/ml. Angio‐tensin II specifically inhibits the inactivation of the conjugated phage by antibodies and as little as 0.5 pg of it was detectable by this system. The purification of antibodies to angiotensin on an angiotensin‐Sepharose immunoadsorbent permitted the evaluation of the antibody concentration in the serum.