Ic cells. Purification through a 12 step sucrose gradient was performed prior to conditioning in vitro and in vivo.Introduction: Infections by two Gram-negative intracellular bacterial pathogens Piscirickettsia salmonis and Francisella noatunensis, are causing main challenges in aquaculture world-wide. F. noatunensis sp hampers the improvement of fish farming depending on cod in and is deleterious to tilapia. P. salmonis infections have already been devastating for salmon aquaculture. As of currently no productive remedies are available against the ailments. Each P. salmonis and F. noatunensis secrete membrane vesicles (MV). Bacterial MV has been reported as potential vaccine candidates for a selection of host including humans, mice and fish against infection brought on by intracellular pathogenic bacteria as they induce each a humoral and cellular immunity.ISEV2019 ABSTRACT BOOKMethods: We’ve isolated MVs from each Francisella and Piscirickettsia by the ultracentrifugation System. The MVs were characterized by their size distribution, by transmission electron microscopy (TEM) and proteomics. Their toxicity had been tested by injecting MVs into each our zebrafish vaccine and challenge model too as in cod, tilapia and salmon. A vaccine trail was performed initially in our zebrafish model, then in cod, tilapia and salmon. Outcomes: The MV size evaluation showed that the MVs size distribution ranged from 2050 nm in size with most ranging from 7000 nm. Both single and double membrane MV had been located inside the population as investigated by TEM. Further, immune-gold labelling revealed the presence of DNA in both populations. Proteomics analysis revealed that the MV content varied in between bacterial strains. Immunization with MV gave PIM1 Species protection against disease caused by each P. salmonis and F. noatunensis in our zebrafish model, however, didn’t guard cod, tilapia nor salmon. Summary/Conclusion: The MVs from P. salmonis and F. noatunensis revealed a related size distribution and that the content contains numerous bacterial virulence factors too as DNA that may be transferred for the host. As for their immunogenic properties this seems to vary between the vaccine and challenge model in comparison with the natural hosts. The use of the MVs as vaccines in their all-natural hosts for instance strain-specificity and cross-immunity need further investigation. Funding: Research Council of Norway (RCN) and University of Oslo.OF14.Bacterial membrane vesicles enter polarised epithelial cells and provide their protein cargo to exosomes Lorinda Turnera, Nestor Solisb, Georg Rammc, Viola Oorschotc, Amanda De PDE3 Biological Activity Paolia, Hassan Chaudhrya, Stuart Manneringd, Stuart Cordwellb, Maria Kaparakis-Liaskose and Richard Ferreroaa Hudson Institute of Healthcare Investigation, Melbourne, Australia; bThe University of Sydney, Sydney, Australia; cMonash University, Melbourne, Australia; dSt. Vincent’s Institute of Health-related Study, Melbourne, Australia; 5Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australiaresistance and apical-basolateral polarity of standard epithelium. For this, colonic epithelial cells from the T84 line were grown on Transwell filters to generate transepithelial electrical resistance (TEER), a measure of epithelial monolayer integrity. The cells had been then cocultured with Alexa Fluor-labelled OMVs from the gastric pathogen, Helicobacter pylori. Outcomes: We showed that H. pylori OMVs readily entered polarised epithelial cells, but had no effect around the TEER nor permeability.