SM1S26

**SM1S26** is a Centyrin, a small engineered protein scaffold derived from the fibronectin type III-binding domain of human tenascin-C, designed as a high-affinity inhibitor of *Staphylococcus aureus* leukocidins, particularly LukED, with a dissociation constant (Kd) of 11.3 nM. It neutralizes bicomponent leukotoxins secreted by *S. aureus*, preventing toxin-mediated cytolysis of human immune cells such as neutrophils by blocking toxin attachment and pore formation. Developed through protein engineering to target multiple *S. aureus* virulence factors including PVL, HlgAB, HlgCB, LukED, and LukAB, SM1S26 demonstrated potent protection in ex vivo human cell assays and in vivo murine models of *S. aureus* intoxication and systemic infection, including prophylactic and therapeutic administration, with enhanced efficacy when fused to an albumin-binding domain for prolonged serum half-life.[1][3][5][9]