C5AR1 and infection: To address the pathogenic role of human C5aR-PVL interaction in vivo and test the efficacy of C5aR blockade as a treatment for S. aureus skin infection, we next infected humanized NSG mice with WT and isogenic PVL- mutant S. aureus strains, and treated the mice either 1 h prior or 3 h after infection with PMX53.