FIG. 7.

Immunization with the LPaV strain reduces lung pathology in B. bronchiseptica- and B. pertussis-infected mice. Mice were immunized with the LPaV strain or sterile PBS and challenged with RB50 (A) or B. pertussis (B) as described in the text. On day 7 postchallenge, lungs were harvested, fixed, and processed for H&E staining. The sections were examined, and pathology was scored in a blinded manner. Representative H&E-stained lung sections are shown along with the mean pathology score for each group. (A) The LPaV-RB50 image shows that there was prominent bronchiole-associated lymphoid tissue, but the airways were generally clear and the alveolar walls were fairly normal (pathology score, 1.5). In contrast, the lung from the mouse treated with PBS and challenged with RB50 had diffuse alveolar wall thickening and airway inflammation (pathology score, 4.3). Magnification, ×100. (B) The LPaV-Bp536 image shows that there was prominent bronchiole-associated lymphoid tissue, patchy alveolar edema, and minimal inflammation (pathology score, 1.6), while the lung from the mouse treated with PBS and challenged with Bp536 was markedly infiltrated by inflammatory cells and edema fluid and there was a reduction in the clear airway space (pathology score, 3.0). Magnification, ×100.