Formyl peptide receptor chemotaxis with

Multiple mechanisms are probably involved in immune-modulating effects of AMPs. A variety of receptors has been described for cathelicidins, however, only one biological function, that of LL-37-mediated chemotaxis of human peripheral blood leukocytes, is associated with a known receptor (formyl peptide receptor like 1), [187]. Human BD-2 recruits mast cells and LL-37 activates epithelial cells through at least 2 classes of receptors [183,202], LL-37 transactivates epidermal growth factor receptor (EGFR) and promotes the release of IL-ip [203], and LL-37-induced maturation of LPS-primed monocytes requires the P2X(7)... 

Another example of a potential receptor relay for leukocyte migration is the N-formylpeptide receptors. By using gene-targeting techniques, Hartt et al. (107) demonstrated that A-formylpeptides can induce two distinct concentration optima for mouse neutrophil chemotaxis by differential interaction with two Af-formyl-peptide receptors FPR and FPR2. 

The formylated peptide fMet-Leu-Phe is probably the most commonly-used activator of neutrophils in vitro. It is used as a model agonist to study receptor-mediated processes, generating intracellular signalling molecules that then activate cell functions. This compound can, depending upon the concentration used, activate many varied functions, such as chemotaxis, aggregation, reactive oxidant production, cytoskeletal changes and (particularly in combination with cytochalasin B) degranulation. 

---