title: IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS : XI. SPECIES DIFFERENCES AMONG BLOOD GROUP A SUBSTANCES.
abstract: The reactions of hog, human, and horse blood group A substances with antibodies produced on injection of these substances into individuals of blood groups B and O have been studied by hemagglutination inhibition and by quantitative precipitin technics. Species differences in reactivity with antisera exist among these blood group A substances. Hog and human A substances are very closely related chemically as evidenced by their extensive cross-reaction while horse A substance crossreacts much less with antisera to both hog and human A substances. Analysis for hexosamine of specific precipitates of hog and human A substances and antibody to human A substance formed as a consequence of heterospecific pregnancy has shown that essentially all of the glucosamine of the blood group substance is precipitated.
authors.affiliation: Departments of Neurology, Bacteriology, and Pediatrics, College of Physicians and Surgeons, Columbia University, and the Neurological Institute and Babies Hospital, Presbyterian Hospital, New York.
authors.forename: E A
authors.initials: EA
authors.lastname: Kabat
authors.forename: H
authors.initials: H
authors.lastname: Baer
authors.forename: R L
authors.initials: RL
authors.lastname: Day
authors.forename: V
authors.initials: V
authors.lastname: Knaub