The DNA fibers of shrimp hemocyte extracellular traps are essential for the clearance of Escherichia coli

Extracellular traps (ETs) are a part of the vertebrate immune response that was only recently discovered. These structures are formed in response to pathogenic invasion and they act to kill the invader. Vertebrate ETs are composed of chromosomal DNA, histone proteins and other antimicrobial cytoplasmic proteins. Pathogenic stimulation was also recently shown to trigger a similar ET response in shrimp hemocytes, and in the present study, we evaluate the role of the DNA fibers in the bactericidal properties of these invertebrate ETs. When the formation of shrimp ETs was disrupted by DNase I, the ETs anti-bacterial activity was also reduced, indicating that the DNA fibers are important for ET-mediated bacterial clearance. We also found that at high bacterial densities, shrimp ETs were a more effective anti-bacterial response than phagocytosis.