Further Observations on the Toxigenic Properties of Hemolytic Streptococci

[摘要] Five hundred and ninety-seven cultures of hemolytic streptococci were classified according to precipitation-group and were examined for toxigenic activity; with 450 the virulence for mice was determined. The highest incidence of virulent strains occurred in group C-G to which many strains from spontaneous infections in animals belong. Although toxigenic activity as demonstrated by the cutaneous reactions induced in rabbits was largely limited to group-A cultures, the majority of which were isolated from human infections, a small number of group-C-G cultures from horses produced toxins.The toxigenic strains were divided into groups on the basis of toxin neutralization by univalent horse-sera of three selected group-A strains. These sera alone or in combination neutralized the toxins of all of the strains of both group-A and C-G. A multivalent antistreptococcal horse-serum prepared with two strains of different toxin-groups was effective in neutralizing the toxins of 147 group-A strains which included representatives of the various toxin-groups.Observations made in the course of this study serve to emphasize further the complex character of the antigenic activity of streptococcal toxins. Within one toxin-group marked differences in toxins were demonstrated by neutralization tests with several heterologous antitoxins and by studies of antigenic activity in goats and rabbits. Thus, the number of toxin-groups defined is dependent upon the valency of the antitoxins used in classification. Furthermore, the antigenic valency of a toxin is in some instances modified by the animal species in which the antitoxin is produced.

[学科分类] 生物科学（综合）