CXCL1 and infection: In contrast, compared to mice infected with RV-A2 alone, mice infected with RV-A1B prior to RV-A2 showed reduced mRNA and protein expression of IL-1β, TNF-α and CXCL1 measured one day after secondary infection (Figure 2B), consistent with the notion that early life (day 6) rhinovirus infection modulates the immune response towards the subsequent (day 13) infection, skewing it towards a type 2 response and away from a type 1 response.