Comparative Immunizing Capacity of BCG and the Proteins and Polysaccharides in Tubercle Bacillus Culture Filtrates

Abstract

In the presence of large inocula of tubercle bacilli previous sensitization with tuberculin protein provided no protection, and appeared possibly to be detrimental. When small inocula were used a definite increase in survival time could be demonstrated in animals previously vaccinated with BCG. In experiments in which such resistance was demonstrated, parallel series of rabbits sensitized with tuberculin protein A (soluble at its iso-electric point) or with tuberculin protein C (insoluble at its iso-electric point) as well as with the small haptenic tuberculin polysaccharide I or with the larger antigenic tuberculin polysaccharide II, did not show increased resistance to tuberculous infection. Electrophoretic changes were demonstrated in antisera to some of these fractions. Even though, by indirect methods, some of these serum components had been shown to have antibodies which possessed anti-infective properties, nevertheless, the rabbits possessing these antisera were not immune.