Agglutinating and Precipitating Capacity of Rabbit Anti- Salmonella typhosa γG and γM Antibodies During Prolonged Immunization

Abstract

Pike, Robert M. (University of Texas Southwestern Medical School, Dallas), Mary L. Schulze, and Cleo H. Chandler . Agglutinating and precipitating capacity of rabbit anti- Salmonella typhosa γG and γM antibodies during prolonged immunization. J. Bacteriol. 92: 880–886. 1966.—Antibody produced in rabbits immunized with acetone-dried typhoid bacilli was followed over a period of 445 days by agglutination and by quantitative precipitation. Repeated injections of vaccine resulted in suppression of antibody titers. Both γG and γM antibodies were rapidly increased by booster injections after rest periods during which titers had decreased to low levels. The O agglutinin titers and the amount of antibody protein, as determined by precipitation with endotoxin, generally were parallel, except in serum specimens in which unusually large proportions of the agglutinating activity were found in the γG fraction. These exceptions were explained by the greater agglutinating capacity of the γM. Endotoxin precipitated about 10 times as much antibody from γG preparations as it did from γM fractions of equivalent agglutinating strength. A much higher proportion of the serological activity, therefore, was found in the γG fractions when antibody was measured by precipitation than when agglutination was used as the measure of activity.