The Specificity of the Agglutinin Reaction for Shigella dysenteriae: II. Agglutinin Absorption Relationships between Shigella dysenteriae and Escherichia coli.

In a previous communication (Mackie, 1938) we have reported observations upon the Shigella dysenteriae agglutinin curves in a group of patients presenting the intestinal pathology of chronic bacillary dysentery and bacteriologic or serologic evdence of infection by these organisms. Fluctuation of the titre curves in individual patients, the common finding of higher titres in the culture-negative cases than in the culture-positive cases, and the infrequency and low titre of normal agglutinins in the control groups, suggest that agglutinins for Shigella dysenteriae may develop in response to non-specific heterologous infection. The studies here reported were undertaken to investigate this possibility. It is known that immunization of an animal against Eberthella typhosa often leads to the production of major agglutinins for the homologous organism, and of minor agglutinins for certain strains of Escherichia coli. Absorption of such a serum by its homologous antigen removes the minor as well as the major agglutinins (Bulloch, 1929). Agglutinins for S. dysenteriae, previously absent, have been observed to appear in the serum of certain patients suffering from chronic ulcerative colitis in the