Polarisation of major histocompatibility complex II host genotype with pathogenesis of European Brown Hare syndrome virus

PLoS One. 2013 Sep 19;8(9):e74360. doi: 10.1371/journal.pone.0074360. eCollection 2013.

Abstract

A study was conducted in order to determine the occurrence of European Brown Hare Syndrome virus (EBHSV) in Denmark and possible relation between disease pathogenesis and Major Histocompatibility Complex (MHC) host genotype. Liver samples were examined from 170 brown hares (hunted, found sick or dead), collected between 2004 and 2009. Macroscopical and histopathological findings consistent with EBHS were detected in 24 (14.1%) hares; 35 (20.6%) had liver lesions not typical of the syndrome, 50 (29.4%) had lesions in other tissues and 61 (35.9%) had no lesions. Sixty five (38.2%) of 170 samples were found to be EBHSV-positive (RT-PCR, VP60 gene). In order to investigate associations between viral pathogenesis and host genotype, variation within the exon 2 DQA gene of MHC was assessed. DQA exon 2 analysis revealed the occurrence of seven different alleles in Denmark. Consistent with other populations examined so far in Europe, observed heterozygosity of DQA (H o = 0.1180) was lower than expected (H e = 0.5835). The overall variation for both nucleotide and amino acid differences (2.9% and 14.9%, respectively) were lower in Denmark than those assessed in other European countries (8.3% and 16.9%, respectively). Within the peptide binding region codons the number of nonsynonymous substitutions (dN) was much higher than synonymous substitutions (dS), which would be expected for MHC alleles under balancing selection. Allele frequencies did not significantly differ between EBHSV-positive and -negative hares. However, allele Leeu-DQA*30 was detected in significantly higher (P = 0.000006) frequency among the positive hares found dead with severe histopathological lesions than among those found sick or apparently healthy. In contrast, the latter group was characterized by a higher frequency of the allele Leeu-DQA*14 as well as the proportion of heterozygous individuals (P = 0.000006 and P = 0.027). These data reveal a polarisation between EBHSV pathogenesis and MHC class II genotype within the European brown hare in Denmark.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Animal Diseases / epidemiology
  • Animal Diseases / genetics*
  • Animal Diseases / virology
  • Animals
  • Bunyaviridae Infections / veterinary*
  • Denmark
  • Exons
  • Genes, MHC Class II*
  • Genes, Viral
  • Genetic Predisposition to Disease
  • Genetic Variation
  • Genotype*
  • Geography
  • Hares / genetics
  • Hares / virology
  • Lagovirus / classification*
  • Lagovirus / genetics
  • Lagovirus / isolation & purification
  • Molecular Sequence Data
  • Phylogeny
  • Sequence Alignment

Associated data

  • GENBANK/JX261937
  • GENBANK/JX261938
  • GENBANK/JX261939
  • GENBANK/JX261940

Grants and funding

The research leading to these results received partial funding from the European Union Seventh Framework Programme (2007–2013) under grant agreement no. 222633 (WildTech) (http://www.wildtechproject.com/wildtech/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding was received for this study.