Figure 2.
Difference in pathologic changes of skin lesions in rabbits injected with different live and heat-killed mycobacteria by prime-boost strategy. (A) Pathologic changes of the primary skin lesions. The rabbit was injected intradermally with about 5 × 106 CFU of live or heat-killed mycobacteria in 100 µl respectively on both flank. (B) Pathologic changes of the skin lesions induced by boosting with homogeneous mycobacteria. Six weeks after the first injection, the rabbits were boosted with the same bacteria at the same dose close to the first injection site. On both the prime and boosting injection, live BCG induced the most severe inflammation reaction, granuloma, liquefaction and ulceration followed by live H37Ra with M. smegmatis being the least pathogenic. All the heat-killed bacteria induced smaller granuloma without liquefaction than the live bacteria. Each point represents the mean of the lesions from both flanks of three rabbits and its standard error, along with the statistical significance: n = 6, **p < 0.05 BCG vs. H37Ra and M. smegmatis, and ***p < 0.05 BCG vs. H37Ra vs. M. smegmatis.