isohemagglutinogen
noun
iso·hem·ag·glu·tin·o·gen
variants:
or chiefly British isohaemagglutinogen \ -ˌhē-mə-ˌglü-ˈtin-ə-jən 
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Medical Definition of isohemagglutinogen
: an antigen inducing the production of or reacting with specific isohemagglutinins