Conversely, infection of cells with RCAN1-4 lentivirus short hairpin (Sh) RNA which ablates RCAN1-4 protein expression (Fig. 5A), augmented the PGF2α-FP receptor activation of CXCL8 mRNA (Fig. 5B; P < 0.01) and protein (Fig. 5C; P < 0.01) confirming that RCAN1-4 is a negative regulator of CXCL8. This evidence concerns the gene CXCL8 and infection.