CCL4 and infection: Furthermore, a qPCR analysis of macrophage inflammatory responses revealed that infection with the rough strains for 24 h significantly upregulated the expression of pro-inflammatory cytokines IL−1β and IL−6 (Figure 5b,c), chemokines MCP1 and MIP1β (Figure 5d,e), and inducible nitric oxide synthase (iNOS) (Figure 5f) compared to the parental M5 strain.