Bacterial antiviral STANDs (Avs) are evolutionarily related to the nucleotide-binding oligomerization domain (NOD)-like receptors widely distributed in immune systems across animals and plants. EfAvs5, a type 5 Avs from Escherichia fergusonii, contains an N-terminal SIR2 effector domain, a NOD, and a C-terminal sensor domain, conferring protection against diverse phage invasions. Despite the established roles of SIR2 and STAND in prokaryotic and eukaryotic immunity, the mechanism underlying their collaboration remains unclear. Here we present cryo-EM structures of EfAvs5 filaments, elucidating the mechanisms of dimerization, filamentation, filament bundling, ATP binding, and NAD