CXCL12 and infection: Salmonella infection induced ccl38a.4 gene, encoding CCL2, a key chemokine of macrophage migration that binds the CCR2 receptor (Cambier et al., 2014) at 4 hpi but has no effect on cxcr4b and sdf1 (cxcl12a), suggesting a role of the Ccl2/Ccr2 axis in macrophage mobilization to the infection site (Figure 2A and Figure 2—figure supplement 1).