The demonstration of type specific streptococcal antibody by a hemagglutination technique employing tannic acid

Immunity to the group A streptococcus has been shown to be associated with the formation of anti-body against the type-specific component of the streptococcus, the M protein of Lancefield (1, 2). The techniques that have been employed in studies of this antibody include agglutination (3), precipi-tation (4), mouse protection (5), and bacterio-stasis (6, 7). For practical purposes, in the study of human infections, all of these methods except the bacteriostatic test have proved to be unsatis-factory. The latter test, as described by Roth-bard (7), yields reliable results but the numerous technical difficulties inherent in the procedure have made it desirable to find another method for the demonstration of type specific antibodies. The presence of various antibodies has been dem-onstrated by the adsorption of antigenic com-ponents of bacteria to the surface of erythrocytes, rendering the cells agglutinable by specific antisera. The widest application of this technique has been in the demonstration of antibodies to a component of the tubercle bacillus (8, 9); the technique has also been applied in serological studies of H. influ-enzal meningitis (10), histoplasmosis (11), gland-ers (12), scrub typhus (13), mumps (14), tula-remia (15), streptococcal infections and rheumatic fever (16), and infections with E. coli (17). In this laboratory, repeated attempts were made to adsorb M protein to erythrocytes and then dem-onstrate their agglutination by specific antibody. No adsorption could be demonstrated, even when erythrocytes from sheep, rabbit, and man were ex-1This work was done under the sponsorship of th