Abstract 2864 Studies on the host selectivity of the staphylococcal innate immune evasion protein, SPIN

The Staphylococcal Peroxidase Inhibitor (SPIN) is a small, secreted protein that inhibits myeloperoxidase (MPO) activity. SPIN blocks the MPO active site and prevents production of cytotoxic hypochlorous acid (HOCl) within the neutrophil phagosome, thereby enabling evasion of innate immunity by bacteria. Staphylococcus aureus is primarily a pathogen of humans and previous studies have shown that its SPIN protein cannot inhibit MPO from many non-human species (i.e. horse, cattle, rabbit, and mouse).