Sialic Acid in the 'F. tularensis' and 'F. novicida' Antigens.

摘要

Sialic acid was revealed in the antigens of virulent (503/830 and Schu) and vaccine (Schu-attenuated and 15-reduced) strains of F. tularensis and also in the antigens of F. novicida isolated by the treatment with trichloracetic acid, by the thiobarbiturate method of Warren. Its content depended on the culture virulence. Sialic acid was absent in the antigens of avirulent strains of the causative agent of tularemia (503-attenuated, 15-attenuated and 21/400), but, in difference from the virulent strains, there was revealed 2-desoxyribose on account of the presence of DNA. Serological activity of F. tularensis antigen decreased only 15 times in the antibody neutralization reaction after a complete release of sialic acid as a result of hydrolysis of the preparation in 0.1, H2SO4 at 80 C for one hour, i.e. it persisted at a sufficiently high level. On the basis of investigations carried out it can be admitted that there existed a chemical association between the sialic acid and other composites in the polysaccharide of the virulent and the vaccine strains of F. tularensis, but that this acid played no significant role in the manifestation of specific properties by the antigen. (Author)