Effect of BCG Vaccination and Chemotherapy on Experimental Tuberculosis in Mice

[摘要] In recording microscopic counts of acid-fast bacilli for lung, liver and spleen of mice, intravenously infected with Mycobacterium tuberculosis , it was found that in the case of untreated control mice there is a close correlation between the counts and the progress of the infection, as judged by the time of survival and the change in body weight. The counts were made in stained contact films prepared with the freshly cut organs.In mice, which were given BCG vaccine prior to infection or received chemotherapy, the counts were found markedly reduced, as compared to the counts in the infected controls, the degree of reduction depending upon the form of treatment and the organ examined. When, in analogy to the untreated control mice, the counts of acid-fast bacilli, determined for treated mice, are taken as a measure of the degree of infection, the analysis of the counts leads to the following conclusions: 1. (1) Chemotherapy (streptomycin + PAS) is more effective in the lung than in the two other organs.2. (2) Subcutaneous vaccination with a BCG culture, grown in tween-albumin fluid medium, has a suppressive action upon the tuberculous infection, leading to markedly reduced microscopic counts of acid-fast bacilli in lung, liver and spleen.3. (3) In the lung, which, according to gross examination and microscopic counts, is the organ most affected by the infection, chemotherapy is more effective than BCG vaccination.4. (4) The lung is the only organ, of those studied, in which there is, according to the counts, a favourable additive effect when BCG vaccination is combined with subsequent chemotherapy.5. (5) BCG vaccination is as effective against a streptomycin-resistant strain of M. tuberculosis as it is against a streptomycin-sensitive culture.The rates of survival, recorded for the 33rd day after infection and the histopathological changes observed in sections of lung, liver and spleen, support the conclusions as set forth under points (2) and (5). The microscopic estimations, in lung sections, of the percentage destruction of alveolar spaces are in agreement with conclusion (3).The described close correlation between the degree of tuberculous involvement and the counts of acid-fast bacilli, recorded for the three organs, appears to be characteristic for mice and does not necessarily apply to the tuberculous infection of other species. The described counting technique is applicable in the case of mice only.Extensive perivascular accumulations of lymphocytes are described for liver and lung of the mice which had undergone BCG vaccination or chemotherapy.

[学科分类] 生物科学（综合）