An in vitro method for the analysis of hemocyte-derived extracellular traps in shrimp

The formation of extracellular traps (ETs) is a cell death mechanism relying on the release of nucleic acids in response to different stimuli. More recently, ETs have been recognized as an important cellular immune response since they are able to entrap and kill various microorganisms. The main goal was to describe a methodology to induce and visualize the in vitro formation of ETs by shrimp hemocytes. ETs formation was induced by the incubation of hemocyte monolayers from naïve shrimp (Penaeus vannamei) with a standard dose of Vibrio parahaemolyticus M0905. Following fixation, slides were stained with 4',6-diamidino-2-phenylindole (DAPI) and imaged by fluorescence microscopy. The methodology proposed in this study successfully induced the formation and release of hemocyte-derived ETs in penaeid shrimp. The procedure described here can be used as a novel immune marker to assess shrimp health status.