Virus Research 210 (2015) 327–336 Contents lists available at ScienceDirect Virus Research j ourna l h o mepa ge: www.elsevier.com/locate/virusres Unravelling the genetic components involved in the immune response of pigs vaccinated against influenza virus Ricardo Zanella a,b,1 , Danielle Gava a,1 , Jane de Oliveira Peixoto a , Rejane Schaefer a , Janice Reis Ciacci-Zanella a , Natalha Biondo c , Marcos Vinicius Gualberto Barbosa da Silva d , Maurício Egídio Cantão a , Mônica Corrêa Ledur a,∗ a Embrapa Swine and Poultry, Concórdia, SC, Brazil b Present Address: University of Passo Fundo, Passo Fundo, RS, Brazil c Santa Catarina State University, Lages, SC, Brazil d Embrapa Dairy Cattle, Juíz de Fora, MG, Brazil a r t i c l e i n f o Article history: Received 29 April 2015 Received in revised form 31 August 2015 Accepted 4 September 2015 Available online 8 September 2015 Keywords: GWAS Swine Influenza A virus Vaccination Immune response a b s t r a c t A genome-wide association study for immune response to influenza vaccination in a crossbred swine population was conducted. Swine influenza is caused by influenza A virus (FLUAV) which is considered one of the most prevalent respiratory pathogens in swine worldwide. The main strategy used to control influenza in swine herds is through vaccination. However, the currently circulating FLUAV subtypes in swine are genetically and antigenically diverse and their interaction with the host genetics poses a chal- lenge for the production of efficacious and cross-protective vaccines. In this study, 103 pigs vaccinated with an inactivated H1N1 pandemic virus were genotyped with the Illumina PorcineSNP60V2 BeadChip for the identification of genetic markers associated with immune response efficacy to influenza A virus vaccination. Immune response was measured based on the presence or absence of HA (hemagglutinin) and NP (nucleoprotein) antibodies induced by vaccination and detected in swine sera by the hemagglu- tination inhibition (HI) and ELISA assays, respectively. The ELISA test was also used as a measurement of antibody levels produced following the FLUAV vaccination. Associations were tested with x 2 test for a case and control data and using maximum likelihood method for the quantitative data, where a moderate association was considered if p < 5 × 10 -5 . When testing the association using the HI results, three mark- ers with unknown location and three located on chromosomes SSCX, SSC14 and SSC18 were identified as associated with the immune response. Using the response to vaccination measured by ELISA as a qual- itative and quantitative phenotype, four genomic regions were associated with immune response: one on SSC12 and three on chromosomes SSC1, SSC7, and SSC15, respectively. Those regions harbor impor- tant functional candidate genes possibly involved with the degree of immune response to vaccination. These results show an important role of host genetics in the immune response to influenza vaccination. Genetic selection for pigs with better response to FLUAV vaccination might be an alternative to reduce the impact of influenza virus infection in the swine industry. However, these results should to be validated in additional populations before its use. © 2015 Elsevier B.V. All rights reserved. 1. Introduction In the livestock sector, most of the economic losses are caused by infectious pathogens (Miller et al., 2013). To mitigate those losses, ∗ Corresponding author at: Embrapa Swine and Poultry, Animal Health and Genetics Laboratory. BR 153, Km 110, Vila Tamanduá 89700-000, Concórdia, Santa Catarina, Brazil. Fax: +55 49 34410497. E-mail address: monica.ledur@embrapa.br (M.C. Ledur). 1 These authors contributed equally to this work. several strategies have been proposed and implemented. Currently, vaccination is considered the most powerful tool to control and to diminish the disease burden, reducing the clinical signs and the transmission of the disease within and across herds (Kimman et al., 2007). However, the immune response to vaccination can vary among individuals, with animals not responding at all or with different levels of response (Poland et al., 2014; Rajao et al., 2014). It has been proposed that the immune response to vaccination is inherited as a complex quantitative trait with variation result- ing from environmental and genetic factors (Newport et al., 2004). http://dx.doi.org/10.1016/j.virusres.2015.09.003 0168-1702/© 2015 Elsevier B.V. All rights reserved.