HEMAGGLUTININS IN PLASMA OF CATFISH (ICTALURUS NEBULOSUS) INJECTED WITH SALIVA FROM HUMAN SECRETORS OF VARIOUS A-B-O BLOOD GROUPS

Serums from non‐immunized catfish contain hightitered thermolabile hemolytic activity for all human red cells, and for red cells of other species such as rabbits. However, after heat inactivation, these sera only weakly agglutinate human red cells. After immunization with human saliva from A‐B‐H secretors, catfish produce potent agglutinins which clump to approximately the same high titer human red cells of all A‐B‐O blood groups as well as red cells from anthropoid apes (chimpanzees and gibbons). These sera do not agglutinate red cells from human beings of the Bombay type, or monkey red cells (baboon), or animal red cells (sheep). The antibody responsible for these reactions has been designated anti‐Z and detects a serological specificity (blood factor) which is inhibited by A‐B‐H secretor saliva, and which appears to be closely associated with A‐B‐H blood group substances. By absorption, from the sera of catfish injected with group O saliva anti‐H has been fractionated which differs from anti‐H lectin Ulex europeus in its cross reactions with gibbon red cells. From the serums of the catfish immunized with group A saliva, besides anti‐Z and anti‐H, anti‐A, but not anti‐C, could be fractionated. No anti‐A1 component could be fractionated by absorption with A2 cells. From the serums of catfish immunized with group B saliva, the expected anti‐B together with weak anti‐C could be fractionated by absorption, besides anti‐Z and anti‐H. These findings throw further light on the serological specificities of the human A‐B‐H substances of red cells and secretions and illustrate the usefulness of fish as experimental animals for serological investigations. 1968 AABB