“Impact of oral immune priming on Manila clam (Ruditapes phillippinarum) microbiota (7219)”

Impact of oral immune priming on Manila clam (Ruditapes phillippinarum) microbiota

Growing evidence demonstrates that invertebrates display adaptive-like immune abilities, commonly known as “immune priming”: if invertebrates were previously exposed to the pathogen they will be better protected to subsequent re-infections. Immune priming has been demonstrated to date in a few species from different Phyla (Ctenophora, Cnidaria, Mollusca, Nematoda and Arthropoda). However, it has been barely studied in bivalve mollusks, and particularly in clams, despite its ecological significance and the high economic impact in worldwide aquaculture, such as Manila clam (Ruditapes phillippinarum) a Top Ten species for this industry.
Immune priming has been triggered by injection of the pathogen in the host in most bivalve’s reports, including Manila clam. However, bivalves are filter feeders and the oral route is their natural route of infection and, thus, the best way to obtain an accurate picture about how immune priming works. Here, we have established Manila clam as an experimental model organism for studying oral immune priming to mimic the bivalve’s natural route of infection. Manila clam juveniles orally exposed to a sub-lethal concentration of the bacterial pathogen Vibrio europaeus showed increased survival upon a subsequent challenge with a lethal dose of this bacterium. The impact of the immune priming on the Manila clam microbiota was also investigated for first time. Clam’s microbiota was characterized by full-length 16S rRNA metabarcoding and the bacterial pathogen, Vibrio spp and total bacteria quantified by qPCR. Different bacterial taxa and species overrepresented were identified in primed clams and the bacterial dynamics due to immune priming were established. Although the exact mechanism of oral immune priming in clams is unclear, we have demonstrated that host’s microbiota shifted as consequence of immune priming. Our results suggested that microbiota could play an important role in this phenomenon, and thus, immune priming could be influenced by the interaction of hosts/symbionts/pathogens.

1. Dubert, Javier, University of Santiago de Compostela, Presenter
2. Rodino-Janeiro, Bruno K., University of Santiago de Compostela, Author
3. Rodriguez, Sergio, University of Santiago de Compostla, Author
4. Dieguez, Ana L., University of Santiago de Compostela, Author
5. Toranzo, Alicia E., University of Santiago de Compostela, Author