/ree ay"jin, -gin/ , n. Immunol.
1. Also called Wassermann antibody . an antibody formed in response to syphilis and reactive with cardiolipin in various blood tests for the disease.
2. an antibody found in certain human allergies, as hay fever and asthma.
[ 1910-15; Reagin, equiv. to reag ( ieren ) to react + -in -IN 2 ]