The fMLP is a well-known leukocyte chemoattractant which binds to formyl peptide receptors coupled to guanine nucleotide regulatory proteins (G proteins) and activates several important signal transduction pathways that, in turn, cause biochemical responses accountable for physiological defence against bacterial infection and cell damage, including phospholipases C, D, and A2 (PLC, PLD, and PLA2), phosphatidylinositol-3-kinase (PI3K), PKC, and MAPKs [33]. This evidence concerns the gene FPR1 and bacterial infectious disease.