This linear peptide is derived from the C-terminus of the chemokine, complement fragment 5 anaphylatoxin (C5a). This peptide functions to inhibit C5a binding and function at human and rat C5a receptors. C5a is crucial to triggering cellular immune responses and its overexpression is involved in arthritis, Alzheimer’s disease, cystic fibrosis, systemic lupus erythematosus, and other immunoinflammatory diseases