[Frontiers in Bioscience 3, c27-33, May 1, 1998] |
LURIE’S TUBERCLE-COUNT METHOD TO TEST TB VACCINE EFFICACY IN RABBITS
Departments of Environmental Health Sciences, Molecular Microbiology and Immunology, and Epidemiology, School of Hygiene and Public Health; and the Department of Pathology, School of Medicine, The Johns Hopkins University, Baltimore, Maryland 21205
Received 3/9/98 Accepted 3/14/98
11. APPLICATION OF THE TUBERCLE COUNT METHOD TO GUINEA PIGS AND MICE
In guinea pigs, the Smith (44,45) and the Horwitz (46,47) groups counted the primary lesions produced by the inhalation of virulent tubercle bacilli. The Smith group showed that when guinea pigs inhaled very low doses of virulent tubercle bacilli (strain H37Rv), the number of visible primary pulmonary tubercles was reduced about 50% by prior BCG vaccination (44,45). However, the tubercle count method could be more effectively used in guinea pigs if they were made to inhale a semi-virulent strain of human- or bovine-type tubercle bacillus, preferably a strain in which at least 200 inhaled bacillary units (rather than 3 such units) would be required to produce one visible primary pulmonary tubercle in unvaccinated animals. Smith’s group clearly showed that more inhaled human-type tubercle bacilli were required to generate one primary pulmonary tubercle in guinea pigs if the bacilli were of a reduced virulence (48).
Except for the preliminary experiments of D.W. Smith mentioned above in "Tuberculosis in different species," no research group, to our knowledge, has counted primary pulmonary tubercles in mice. We did, however, make rather accurate counts of primary microscopic pulmonary lesions in mice that inhaled Pseudomonas pseudomallei (49-51). Therefore, the tubercle count method could also be developed for mice that inhaled tubercle bacilli, especially if these bacilli were of somewhat reduced virulence.