English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A radioimmunoassay procedure is described for the detection of cholera toxin and its component polypeptide chains. Cholera toxin, A subunit, B subunit, α chain, and γ chain were iodinated by the chloramine T procedure. Radiolabeling did not significantly alter the polyacrylamide electrophoretic migration patterns of the toxin or its components. Moreover, radiolabeled toxin, B subunit, and α chain preparations retained substantial ability to bind to intestinal mucosal homogenates. The minimal amount of antitoxin detectable with radiolabeled toxin was 0.04 antitoxin units/ml. Substitution of radiolabeled B subunit, A subunit, and α chain for radiolabeled toxin decreased the sensitivity of the test. Radiolabeled γ chain did not bind to the antitoxin preparation. Competitive inhibition studies, with titrated anti-choleragen serum and radiolabeled toxin or components, indicated that the minimum concentration of toxin detectable was 7.0 × 10−8 μmol/ml at a 90% inhibition level. The A subunit and α chain preparations inhibited the binding of the radiolabeled B subunit to antitoxin sites. Conversely, B subunit inhibited the binding of radiolabeled A subunit and α chain to antitoxin. The γ chain did not show any reaction with antitoxin or cross-reaction with either whole toxin or its components. These results strongly suggest that the A subunit and the α chain contain antigenic determinant(s) that are common to the B subunit. The B subunit (β chain) and the α chain of cholera toxin may therefore contain region(s) of chemical similarity.

Radioimmunoassay for the Antigenic Determinants of Cholera Toxin and Its Components