Please cite this article in press as: Breard E, et al. Evaluation of adaptive immune responses and heterologous protection induced by inactivated bluetongue virus vaccines. Vaccine (2014), http://dx.doi.org/10.1016/j.vaccine.2014.11.053 ARTICLE IN PRESS G Model JVAC-15966; No. of Pages 7 Vaccine xxx (2014) xxx–xxx Contents lists available at ScienceDirect Vaccine j our na l ho me page: www.elsevier.com/locate/vaccine Evaluation of adaptive immune responses and heterologous protection induced by inactivated bluetongue virus vaccines Emmanuel Breard a,∗,1 , Guillaume Belbis b,1 , Cyril Viarouge a , Kyriaki Nomikou c , Andy Haegeman d , Kris De Clercq d , Pascal Hudelet e , Claude Hamers f , Francis Moreau g , Thomas Lilin g , Benoit Durand h , Peter Mertens c , Damien Vitour a , Corinne Sailleau a , Stéphan Zientara a a ANSES, UMR 1161 Virologie ANSES-INRA-ENVA, 23 avenue du Général de Gaulle, 94704 Maisons-Alfort, France b Université Paris-Est, Ecole Nationale Vétérinaire d’Alfort, Unité de Pathologie du Bétail, 7 avenue du Général de Gaulle, 94704 Maisons-Alfort, France c Vector-Borne Diseases Programme, The Pirbright Institute, Pirbright, Woking, Surrey GU24 0NF, United Kingdom d CODA–CERVA, Department of Virology, Ukkel, Belgium e MERIAL S.A.S., 254 Rue Marcel Mérieux, 69007 Lyon, France f MERIAL S.A.S., P.I. Plaine de l’Ain, Allée des Cyprès, 01150 Saint-Vulbas, France g Université Paris-Est, Ecole Nationale Vétérinaire d’Alfort, Centre de recherche biomédicale, 7 avenue du Général de Gaulle, 94704 Maisons-Alfort, France h ANSES, unité Epidémiologie, 23 avenue du Général de Gaulle, 94704 Maisons-Alfort, France a r t i c l e i n f o Article history: Received 22 October 2013 Received in revised form 20 November 2014 Accepted 28 November 2014 Available online xxx Keywords: Bluetongue virus disease Inactivated vaccines Experimental infection Heterologous challenges Sheep a b s t r a c t Eradication of bluetongue virus is possible, as has been shown in several European countries. New serotypes have emerged, however, for which there are no specific commercial vaccines. This study addressed whether heterologous vaccines would help protect against 2 serotypes. Thirty-seven sheep were randomly allocated to 7 groups of 5 or 6 animals. Four groups were vaccinated with commercial vaccines against BTV strains 2, 4, and 9. A fifth positive control group was given a vaccine against BTV-8. The other 2 groups were unvaccinated controls. Sheep were then challenged by subcutaneous injection of either BTV-16 (2 groups) or BTV-8 (5 groups). Taken together, 24/25 sheep from the 4 experimental groups developed detectable antibodies against the vaccinated viruses. Furthermore, sheep that received het- erologous vaccines showed significantly reduced viraemia and clinical scores for BTV-16 when compared to unvaccinated controls. Reductions in clinical signs and viraemia among heterologously vaccinated sheep were not as common after challenge with BTV-8. This study shows that heterologous protection can occur, but that it is difficult to predict if partial or complete protection will be achieved following inactivated-BTV vaccination. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Bluetongue (BT) is an infectious, OIE-listed arboviral disease that infects ruminants [1]. The disease is caused by viruses belonging to Bluetongue virus species [2]. There are 26 bluetongue virus (BTV) serotypes, which raise type specific neutralising antibodies (NA) during infection of their hosts [3]. BTV is transmitted primarily by biting midges (Culicoides spp.) but can be transmitted vertically or via an oral route [4–6]. Since the 20th century, 10 serotypes ∗ Corresponding author. Tel.: +33 695063201; fax: +33 143689762. E-mail address: emmanuel.breard@anses.fr (E. Breard). 1 Both authors contributed equally. have been detected in Europe, some of them on several different occasions [7]. After the emergence of BTV in Europe (1998), the first suc- cessful inactivated vaccine (IV) protected against BTV-2 [7–11]. Subsequently, monovalent and bivalent IV were developed, used in the field [9,10] and efficient for eradication of different homol- ogous BTV serotypes [12–14]. Since 2011, several countries that were previously infected with serotype 1, 2, 4 or 8 returned to freedom-from-disease after mass vaccination campaigns [7,11]. Animals vaccinated with these IV develop protective immune responses against the homologous serotype(s). The BTV outer- capsid proteins VP2 and VP5 (particularly VP2) are the BTV proteins inducing NA [15]; VP2 is also the major protein involved in serotype determination [16,17]. Sheep inoculated with VP2 alone also http://dx.doi.org/10.1016/j.vaccine.2014.11.053 0264-410X/© 2014 Elsevier Ltd. All rights reserved.