Immune responses in experimental tuberculosis after bacillus Calmette-Guerin vaccination and challenge with H37RV
Venkataraman, M.; Kumar, R.; Bhuyan, U.N.; Malaviya, A.N.; Mohapatra, L.N.
Indian Journal of Medical Research 64(11): 1581-1591
1976
ISSN/ISBN: 0019-5340 PMID: 828615 Document Number: 96984
The immunologic responses to purified protein derivative of tuberculin were studied in groups of guinea-pigs after vaccination with BCG and after challenge with Mycobacterium tuberculosis strain H37Rv in vaccinated and unvaccinated animals. The progress of disease in the latter animals was also observed and scored microscopically. The mean diameter of skin reaction and the macrophage migration inhibition reached their peaks at 3 and 4 wk, respectively, after vaccination and were maintained up to 12 wk. Antibodies could not be detected in the sera of these animals. In the unvaccinated animals infected with M. tuberculosis, the size of the skin reaction increased up to 5 wk after challenge and remained more or less constant thereafter. The maximum mean macrophage migration inhibition was observed at the end of 3 wk. Antibodies were not detected in the sera of these animals. The mean peak microscopic score observed at the end of 5 wk was maintained at the same degree up to 8 wk, after which mortality was observed in many animals. The challenge infection did not much alter the existing skin reaction and macrophage migration inhibition in the vaccinated animals. Many vaccinated animals showed antibodies from the 2nd wk of challenge onwards. In this group, the histological score reached its peak at 3 wk of challenge. It gradually decreased to a residual level by 8 wk and persisted up to 24 wk. A slight increase in the score was noticed at the end of 44 wk. Cultures of spleen at the latter stage yielded M. tuberculosis. The significance of immune responses (particularly the cell mediated type) in relation to protection and tissue damage is discussed.