the antibody which is involved in allergic reactions, causing the release of histamine when it combines with antigen in tissue, and capable of producing sensitivity to the antigen when introduced into the skin of a normal individual.
the substance in the blood which is responsible for a positive response to the Wassermann test: [as modifier]:a reagin test [count noun]:reagins are measured by either complement fixation or flocculation tests
Derivatives
reaginic
adjective
Origin:
early 20th century: coined in German from reagieren 'react'
