Formylpeptide Receptor Antibodies

The human formyl peptide receptor family comprises three class A G protein-coupled receptors, FPR1, FPR2 (also known as ALX), and FPR3. FPR1 recognizes N-formylated peptides released by bacteria or damaged mitochondria, allowing immune cells to detect both infection and tissue injury. FPR2 recognizes a broader range of ligands, including formylated peptides, annexin A1-derived peptides, and the lipid mediator lipoxin A₄, and can promote either inflammation or its resolution depending on the ligand and cellular context. FPR3 responds to the endogenous acetylated peptide F2L, although its physiological role remains less well defined. These receptors signal mainly through Gi/o and are expressed primarily in innate immune cells, with FPR1 and FPR2 prominent in neutrophils and FPR3 reported in monocytes and dendritic cells. FPR1 activation drives neutrophil chemotaxis and can trigger degranulation and reactive oxygen species production. Agonist exposure can induce receptor phosphorylation, β-arrestin recruitment, desensitization, and internalization, with the extent of these responses varying by subtype and ligand. The small-molecule FPR2 agonists ACT-389949 and BMS-986235 have entered early clinical testing. No drug that selectively targets an FPR subtype is currently approved for therapeutic use.