The early stages of the immune response of the European abalone Haliotis tuberculata to a Vibrio harveyi infection Marion Cardinaud a, *, Nolwenn M. Dheilly b , Sylvain Huchette c , Dario Moraga a , Christine Paillard a, ** a UMR 6539-LEMAR (Laboratoire des Sciences de l’Environnement Marin), IUEM (Institut Universitaire Européen de la Mer), Université de Bretagne Occidentale (UBO), CNRS, IRD, Ifremer, Technopôle Brest Iroise, 29280 Plouzané, France b School of Marine and Atmospheric Sciences, Stonybrook University, Stony Brook, NY 11794-5000 USA c France Haliotis, Kerazan, Lilia, 29880 Plouguerneau, France ARTICLE INFO Article history: Received 14 November 2014 Revised 25 February 2015 Accepted 26 February 2015 Available online Keywords: Abalone immune response Gene expression Pathogen quantification Flow cytometry Vibrio harveyi A B ST R AC T Vibrio harveyi is a marine bacterial pathogen responsible for episodic abalone mortalities in France, Japan and Australia. In the European abalone, V. harveyi invades the circulatory system in a few hours after exposure and is lethal after 2 days of infection. In this study, we investigated the responses of European abalone immune cells over the first 24 h of infection. Results revealed an initial induction of immune gene expression including Rel/NF-kB, Mpeg and Clathrin. It is rapidly followed by a significant immuno- suppression characterized by reduced cellular hemocyte parameters, immune response gene expressions and enzymatic activities. Interestingly, Ferritin was overexpressed after 24 h of infection suggesting that abalone attempt to counter V. harveyi infection using soluble effectors. Immune function alteration was positively correlated with V. harveyi concentration. This study provides the evidence that V. harveyi has a hemolytic activity and an immuno-suppressive effect in the European abalone. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Vibriosis is the most common disease caused by pathogenic bac- teria in halophilic environment and affects a large panel of organisms such as humans, fishes and marine invertebrates. In humans, vib- riosis is usually associated with an exposure or absorption of contaminated water or with a zoonosis process, and the regular symptoms are gastroenteritis, tissue lesions and septicemia (Austin, 2010). In marine organisms, several pathogenic Vibrio species are responsible for serious losses in natural populations or in aquacul- ture stocks. Vibrio pathogens have various virulence strategies in marine invertebrates and may invade their hosts through differ- ent ways and at different stages of the life cycle. It has been notably described that Vibrio parahaemolyticus and Vibrio harveyi target, re- spectively, the digestive tractus of the neritid gastropod Clithon retropictus and the cultured juveniles of the shrimp Penaeus monodon or larvae of the lobster Jasus verreauxi (Diggles et al., 2000; Kumazawa and Mine, 2001; Leaño et al., 1998). Vibrio pathogens may also gen- erate epidermal ulcerations and hemocytic inflammation, causing the necrosis of diverse tissues, as observed in cultured oyster Crassostrea gigas infected by Vibrio splendidus (Sugumar et al., 1998), in cultured cuttlefishes from the genus Sepia infected by Vibrio alginolyticus (Sangster and Smolowitz, 2003), in the wild octopus Octopus vulgaris infected by Vibrio lentus (Farto et al., 2003), and in cultured post-larvae of the penaeid shrimp P. monodon infected by V. harveyi (Soonthornchai et al., 2010). Moreover, they may induce a repression effect on immune function via an alteration of cellu- lar capacities or molecular effector synthesis, as described in the Manila clam Ruditapes philippinarum infected by Vibrio tapetis, and in the shrimp Litopenaeus vannamei following a V. alginolyticus in- jection (Allam and Ford, 2006; Allam et al., 2006; Brulle et al., 2012; Li et al., 2008). Interestingly, a significant immunosuppression, in- cluding the downexpression of antimicrobial synthesis, has also been observed in the coral Pocillopora damicornis infected by Vibrio coralliilyticus (Vidal-Dupiol et al., 2014). The European abalone hemolymph is constituted for a high ma- jority by a single differentiated cell population, assimilated to hyalinocyte-type cells, which present remarkable adhesion and ag- gregation capacities – 56% of the cells adhere within 15 min to the substratum, and assume immune function (Travers et al., 2008b). The remaining circulating cells are undifferentiated blast cells. * Corresponding author. UMR 6539-LEMAR (Laboratoire des Sciences de l’Environnement Marin), IUEM (Institut Universitaire Européen de la Mer), Université de Bretagne Occidentale (UBO), CNRS, IRD, Ifremer, Technopôle Brest Iroise, 29280 Plouzané, France. Tel.: + 33 6 71 13 80 77; fax: +33 2 98 49 86 45. E-mail address: marion.cardinaud@gmail.com (M. Cardinaud). ** Corresponding author. UMR 6539-LEMAR (Laboratoire des Sciences de l’Environnement Marin), IUEM (Institut Universitaire Européen de la Mer), Université de Bretagne Occidentale (UBO), CNRS, IRD, Ifremer, Technopôle Brest Iroise, 29280 Plouzané, France. Tel.: + 33 2 98 45 86 50; fax: +33 2 98 49 86 45. E-mail address: christine.paillard@univ-brest.fr (C. Paillard). http://dx.doi.org/10.1016/j.dci.2015.02.019 0145-305X/© 2015 Elsevier Ltd. All rights reserved. Developmental and Comparative Immunology ■■ (2015) ■■–■■ ARTICLE IN PRESS Please cite this article in press as: Marion Cardinaud, Nolwenn M. Dheilly, Sylvain Huchette, Dario Moraga, Christine Paillard, The early stages of the immune response of the Eu- ropean abalone Haliotis tuberculata to a Vibrio harveyi infection, Developmental and Comparative Immunology (2015), doi: 10.1016/j.dci.2015.02.019 Contents lists available at ScienceDirect Developmental and Comparative Immunology journal homepage: www.elsevier.com/locate/dci