Immunological and chemical studies on porcine submaxillary mucins

Porcine submaxillary mucins (PSM) were classified as A, H, AH, and — types according to their ability to inhibit the hemagglutination of human blood group systems. Of 210 glands examined, the following blood group distribution was observed: 35% A, 35% H, 1% AH, and 29%—. The A-type mucin was an effective inhibitor at microgram concentrations, whereas the H-types showed considerably weaker hemagglutination inhibition.
Rabbit antisera to the A and H mucins could be used for typing of human blood groups A and H; no cross-reactivity was observed with the other types. The A-type PSM antisera were adsorbed by human red blood cells of the A type only. Immunodiffusion and immunoelectrophoretic studies of rabbit antisera to crude mucins revealed many antigenic components, but antisera to purified mucin preparations usually developed only two precipitin bands, one of which showed up only after staining for proteins.
PSM was prepared from individual glands of known blood group types by a slight modification of a previously described method. Chemical analyses showed that the variation in composition of individual glands within a given blood group type was larger than could be attributable to experimental error. In addition, chemical variations were also observed among mucins of A, H, and — blood group types.