Fig. 5: Macroscopic and microscopic illustrations and analysis of lung pathology.

Macroscopic illustrations of the lungs a and microscopic illustrations of hematoxylin and eosin HE-stained lung sections b to exemplify the scoring of the percentage affected lung tissue (shown in the table). a and b, numbers 1–4 are typical for the placebo group and numbers 5 and 6 for the vaccine groups, excluding the outliers. Means and SDs of macroscopically c and microscopically d estimated percentages of affected tissue. The relative lung weight (RLW) was calculated as the ratio of the lung weight at termination to body weight at the day of challenge e. Corresponding RLW’s to the illustrations in a, are shown in the table. Bar in a: 3 cm and bar in b: 0.5 cm. WMW test: *p < 0.05; **p < 0.01 compared with the placebo group.