While the proportion of ICAM-1 negative airways (i.e. airways with ICAM-1 signal comparable to PBS control) was not significantly different across both infection groups at 2 days p.i. (81% vs 91%, p = 0.251), we observed a trend towards a higher percentage of ICAM-1-positive airways in lasR mutant-infected mice at 4 days p.i. compared to wild-type-infected mice (40% vs 18%, p = 0.057, S4F Fig). This evidence concerns the gene ICAM1 and infection.