Scientists at the University of Oregon (UO) have identified a novel protein secreted by a common gut bacterium in zebrafish that reduces inflammation in the gut and delays death by septic shock. By examining how the protein, Aeromonas immune modulator, mutually benefits both the bacteria and their larval zebrafish hosts, the research team says its experiments shed light on how animals and their resident microbes negotiate a moderated level of inflammatory response. “Stable mutualism between a host and its resident bacteria requires a moderated immune response to control bacterial population size without eliciting excessive inflammation that could harm both partners.
Little is known about the specific molecular mechanisms utilized by bacterial mutualists to temper their hosts’ responses and protect themselves from aggressive immune attack. Using a gnotobiotic larval zebrafish model, we identified an Aeromonas-secreted immunomodulatory protein, wrote the investigators.