Mouse complement C5a is a 77-amino acid peptide generated during complement activation from the alpha-chain of complement C5. Mouse C5a shares 60% and 82% amino acid sequence identity to human and rat C5a, respectively. C5a binds to a signaling G-protein coupled receptor (GPCR) (C5aR/CD88), inducing neutrophil chemotaxis and endothelial cell activation. It also triggers an oxidative burst in macrophages and neutrophils, and induces release of histamine in basophils and mast cells.