CXCR2−/− mice show reduced TNF-α and MUC5B mRNA expression 24 h post-RV1B exposure. A-E. Wild type and CXCR2−/− mouse lungs were homogenized in Trizol reagent. RNA was extracted and analyzed for the presence of TNF-α, MIP-2, MUC5B, MUC5AC and GM-CSF by quantitative two-step real time PCR using specific primers and probes. (N=4-5 mice per group, bars represent mean±SEM, *different from respective sham group, p < 0.05, †different from wild type-RV1B treated group, p<0.05, one-way ANOVA.)