NOS2 and infection: Different from LPS-induced infection, 20 mg/kg riboflavin was usually ineffective in zymosan-induced infection in Swiss mice [21], while 300 nM riboflavin supplementation of macrophages stimulated by zymosan significantly decreased Toll-like receptor 6, NO, iNOS, IL-1β, monocyte chemoattractant protein-1 (MCP-1), and keratinocyte chemoattractant levels [97].