CC chemokine ligand-2 synergizes with the nonchemokine G protein-coupled receptor ligand fMLP in monocyte chemotaxis, and it cooperates with the TLR ligand LPS via induction of CXCL8, Gouwy, M., Struyf S., Verbeke H., Put W., Proost P., Opdenakker G., and Van Damme J. , J.Leukoc.Biol., 0/9/2009, Volume 86, Issue 3, Number 680, p.671 - 680, (2009)