FIG. 7.

Histologic appearance of lung tissues harvested from guinea pigs vaccinated with BCG alone or vaccinated with BCG and boosted twice with Mtb72F DNA. (A) Saline control guinea pig euthanized at week 17 showing extensive coalescing granulomatous inflammation with a central focus of necrosis that is undergoing mineralization (arrow). (B) DNA vector control animal (week 30) with region (arrow) of central coagulative necrosis. (C) BCG-vaccinated guinea pig euthanized at week 79. A large granulomatous structure has degenerated with central necrosis (arrow) but with no apparent mineralization. (D) Covaccinated guinea pig surviving to curtailment of the study. Lesions in animals from this group had less-extensive mixed inflammation than animals from other groups, with extensive fibrous connective tissue deposition and small airway reestablishment (arrow), indicating lesion resolution. Bars, 100 μm.