NOD1 and infection: Interestingly, mandarinfish NOD2 showed a more significant increasement when stimulated by PolyI:C than did NOD1 in vivo, however, NOD1 showed significantly higher expression at 24 h post infection in spleen and gill during PolyI:C stimulation, demonstrating that mandarinfish NOD1 and NOD2 may act differently within different tissues in antiviral defense.