Figure 2

Vaccination with rBCG/rAd35 resulted in reduced collagen type I deposition as well as reduced Mtb-specific antigen load in lung and spleen from Mtb-infected animals. (A) Representative immunohistochemical images demonstrate expression and distribution of collagen type I (upper panel) and the Mtb-specific antigen MPT64 (lower panel) in pulmonary TB lesions obtained from the rBCG/rAd35 and BCG/rAd35 vaccine groups as well as the unvaccinated control. Granulomatous areas (gr) with the presence of characteristic giant cells (GC; arrowheads) are shown in the TB lesions. Arrows indicate positive cells (brown), whereas negative cells (blue) were counterstained with hematoxylin. Granulomatous lung tissue contained high levels of collagen type I and MPT64. The median cellularity obtained in the collagen type I staining is also shown in the upper panel. Magnification 125×. (B) The higher-magnification image (600×) reveals cytoplasmic expression of MPT64 and CD68 in cells present in the granulomatous area of a pulmonary TB lesion from an rBCG/rAd35-vaccinated animal. In situ computerized image analysis of collagen type I (C), MPT64 (D) and CD68 (E) expression in TB lung lesion and spleen tissue of rBCG (rBCG/rAd35) or BCG (BCG/rAd35) vaccinated and control (unvaccinated) animals is shown. Data are presented as percent positive area of the total cell area, and the median ± IQR from n = 5–6 animals/group is shown. Statistical significance of differences in protein expression was determined by a nonparametric Kruskal-Wallis test. *P < 0.05, **P < 0.01.