Persistence of goblet cell hyperplasia after viral infection in wild-type and ICAM-1–null mice. (a) Wild-type and ICAM-1–null mice were inoculated with SeV (5,000 EID₅₀) or SeV-UV, and lung sections were stained with PAS and immunostained for MUC5AC mucin. Representative photomicrographs are shown for each genotype (n = 5) at postinoculation day 21. Immunostaining with nonimmune IgG gave no signal above background (data not shown). Bar, 20 μm. (b) Quantification of results shown in a using values for MUC5AC⁺ cells per mm basement membrane (bm) and for MUC5AC⁺ staining as percentage of total epithelial area. Values represent mean ± SEM (n = 10 airways from three to five mice). Similar results were found by analysis of staining intensity (data not shown). (c) Wild-type and ICAM-1–null mice were inoculated with SeV or SeV-UV and subjected to analysis on postinoculation day 77 as described in a and b. Representative photomicrographs and corresponding quantification are shown for MUC5AC immunostaining for each genotype (n = 5). Bar, 50 μm. Results for PAS staining were similar to results at postinoculation day 21 (data not shown). (d) Quantification of results shown in c. Values represent mean ± SEM. No significant difference was detected for postinfection values for wild-type versus ICAM-1–null or for postinfection day 21 versus day 77. *Significant increase from control SeV-UV.