Fig. 9.

Pulmonary histopathology in cotton rats challenged with RSV subgroups A and B. Cotton rats were immunized intramuscularly with MVAIK/RSV/F (panels 3, 7, and 10) or MVAIK/RSV/G (panels 4, 8, and 11) and then challenged five weeks later, with RSV subgroup A (panels 2, 3, 4, 6, 7, and 8) and subgroups B (panels 9, 10 and 11). They were sacrificed four days after the challenge. Histological examination was performed by HE staining of lung tissues (panels 1, 2, 3, and 4) and the results of immuno-staining of bronchiolar regions are shown in panels 5, 6, 7, 8, 9, 10, and 11. Immuno-staining was performed using four clone blend monoclonal antibodies against RSV P, F, and N proteins and anti-mouse IgG conjugated with HRP. HE staining and immuno-staining of normal control are shown in panels 1 and 5.