VCL and infection: We next examined the effect of VCL knock-down on the macrophage cytokine response to infection with P. gingivalis in vitro, and compared this response to that induced by the prototypical TLR2 ligand PAM, which stimulates TLR2 in a strictly MyD88-dependent manner, and to a TLR4 ligand, LPS (lipopolysaccharide).