Studies on prevention of infection (I) Antigenic capacity of enzymati-cally active fractions isolated from tubercle bacilli against tuberculosis of mouse

After grinding the tubercle bacilli cells, both human virulent strain, H37Rv, and avirulent strain, H37Ra, cultured in 5auton's medium, and obtaining three fractions of R1, S1 and R2 (R1, the first sediment; S1, the second supernatant; and R2, the second sediment) by the ultracentrifugation, the authors studied the enzymatic activities and the antigenic capacity against infection of these fractions; and obtained the following results: 1) Although the R1-fraction confers the defensive forte to mice in some degree, because of the presence of living bacilli in the fraction, it is difficult to decide definitely whether the defensive force owes its capability to this fraction or to living bacilli at the present stage of our experiment. 2) The S1-fraction possesses enzymatic activity on various substrates, but it does not confer animal any defensive force against infection. 3) The R2-fraction specifically oxidizes lactate and succinate" and it can markedly impart animal the defensive ability against infection.