Studies in immunochemistry

Abstract

The isolation of a polysaccharide-amino acid complex, showing intense blood group A specificity, from crude gastric mucin, is described. The undegraded A-substance, which is essentially homogeneous, gives rise to slightly opalescent 1% aqueous solns. that show considerable viscosity. The substance inhibits, in extremely small amts., specific isoagglutination and hemolysis of sheep cells by specific anti-A rabbit immune serum. The native A-substance is readily degraded by heat treatment and gives rise to a substance which shows a lower viscosity in aqueous soln. and which possesses a reduced power to inhibit isoagglutination. The partially degraded A-substance, however, shows a slightly increased activity in inhibiting A specific hemolysis. The relationship of the purified undegraded A-substance to the "virulence enhancing" agent in crude gastric mucin is discussed.