N-formyl-methionyl-leucyl-phenylalanine (fMLP), the chemotactic bacterial peptide, was able to specifically attenuate Ca2+ mobilization in human phagocytes induced by SAA, but only at very high concentrations. The bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (fMLF) is one of the first identified and highly potent leukocyte chemoattractants. fMLF interacts with at least two human cell receptors formyl peptide receptor (FPR) and its variant formyl peptide receptor-like 1 (FPRL1), both are members of the seven transmembrane domain, G protein-coupled receptor (GPCR) family.