DNA extracellular traps are part of the immune repertoire of Periplaneta americana

Extracellular traps (ETs), web-like structures composed of DNA and histones, are released by innate immune cells in a wide range of organisms. ETs capture microorganisms, thereby avoiding their spread, and also concentrate antimicrobial molecules, which helps to kill microbes. Although vertebrate innate immune systems share homology with the insect immune system, ETosis have yet to be characterized in insects. Here, we report that the hemocytes of the hemimetabolous insect Periplaneta americana release ETs upon in vitro stimulation. We further discuss the relationship between ETs and nodulation and in controlling bacterial spread in vivo. •Hemocytes from Periplaneta americana cast DNA extracellular traps (ETs) similarly to vertebrates and invertebrate organisms.•Roaches ETs were triggered by LPS, Gram-positive and Gram-negative bacteria.•ETs contribute to a rapid and efficient nodulation needed to block bacteria spread in the insect in vivo.