CXCL12 and infection: To validate the array results, qPCR and ELISA were used to measure changes in mRNA and protein levels of chemokines CXCL12 and CXCL16 as a result of infection with Ct. As seen in Fig. 4A and C, there were no significant differences in expression of mRNA encoding CXCL12 and CXCL16.