RESISTANCE TO SODIUM HYDROXIDE TREATMENT OF ^|^ldquo;IN VIVO GROWN TUBERCLE BACILLI^|^rdquo;

Abstract
"In vivo grown tubercle bacilli" (H37RvL) were separated and purified mechanically from the lungs of moribund mice which had been infected intravenously with 1 mg of H37Rv virulent tubercle bacilli grown on Sauton liquid medium. A striking difference was found in resistance to NaOH treatment between H37RvL and H37Rv. For instance, incubation at 37 C in 5% NaOH for 4 hr. reduced viable counts of H37Rv suspension nearly to one-hundredth, but the same condition did not affect the viability of H37RvL at all. An increase in resistance to NaOH was also observed when H37Rv bacilli had been pretreated with normal mouse lung extract An explanation was presented that the NaOH resistance of H37RvL bacilli is due to possible presence of a protective layer on the bacillary surface which is composed of substances originated from host tissues or cells. Thus, the high NaOH resistance of H37RvL, together with the observation reported in the preceding paper that host-originated acid phosphatase is present on the surface of H37RvL bacilli, will represent one aspect of the host-parasite interaction in tuberculous infection.