Heterogeneous antigenic properties of the porcine reproductive and respiratory syndrome virus nucleocapsid

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus responsible for a widespread contagious disease of domestic pigs with high economic impact. Switzerland is one of the rare PRRSV-free countries in Europe, although sporadic outbreaks have occurred in the past. The PRRSV isolate IVI-1173 from the short outbreak in Switzerland in 2012 was entirely sequenced, and a functional full-length cDNA clone was constructed. Genetic and antigenic characterization of IVI-1173 revealed the importance of amino acid 90 of the nucleocapsid protein N as part of a conformational epitope. IVI-1173 was not detected by SDOW17, a monoclonal antibody against N widely used to detect PRRSV-infected cells. Substitution of alanine at position 90 of N [N(A90)] with a threonine [N(T90)] restored reactivity of vIVI1173-N(T90) to SDOW17 completely. The relevance of this amino acid for the conformational SDOW17 epitope of PRRSV N was further confirmed by the opposite substitution in a functional cDNA clone of the genotype 2 isolate RVB-581. Finally, N proteins from ten genotype 1 strains differing from threonine at position 90 were analysed for reactivity with SDOW17. N(A90) totally disrupted or severely affected the epitope in 7 out of 8 strains tested. Based on these findings, 225 genotype 1 strains were screened for the prevalence of N(A90). N(A90) is rare in classical subtype 1 and in subtype 3 strains, but is frequent in Russian subtype 1 (70%) and in subtype 2 (45%) isolates. In conclusion, this study highlights the variable antigenic properties of N among genotype 1 PRRSV strains.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-016-0399-9) contains supplementary material, which is available to authorized users.

Differentially Expressed MiRNAs and tRNA Genes Affect Host Homeostasis During Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Infections in Young Pigs

“…This change in host resources can then lead to changes in the metabolism of the host that eventually disrupts the proper activation of monocytic cells such as macrophages, allowing the virus to proceed unimpeded by the host cytokines (Langston et al, 2017) toward entry and proliferation. In a 2016 paper, Rappe et al (2016) was able to observe that PRRS type 1 and 2 virus nucleocapsids can contain an amino acid substitution that replaces a threonine with alanine causing the PRRS virus strain in that study to escape immune system protection. Therefore, it is possible that the virus is promoting differential expression of host alanine as a means of both hijacking needed nutrients and avoiding detection by innate immunity.…”

A Triple Amino Acid Substitution at Position 88/94/95 in Glycoprotein GP2a of Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV1) Is Responsible for Adaptation to MARC-145 Cells

“…The mutations (V88F, M94I, F95L) were individually introduced by the Q5 Site-Directed Mutagenesis Kit (New England Biolab, Ipswich, MA, USA) in the plasmid clone, pIVI-1173 [38] containing the full-length cDNA of the infectious genome of the PRRSV1 IVI-1173 strain [GenBank: KX622783]. Primers were designed through NEBaseChanger () (Table 1).…”

“…Briefly, MARC-145 cells were infected with wild-type and mutant variants at a MOI of 0.1. After 1 and 12 h post-infection (hpi), cells were fixed with ice cold (−20 °C) methanol prior to immunofluorescence staining with primary monoclonal antibodies 13E2 against PRRSV nucleocapsid protein (IgG2a, 1:50) [38]. As control, 1C11 against gB of PrV (IgG2a, 1:50) was used as isotype matched irrelevant antibody [42].…”

Accurate and precise real-time RT-PCR assays for the identification of astrovirus associated encephalitis in cattle

“…A cDNA sequence corre s ponding to the entire BoAstV-CH13 reference genome (GenBank accession number NC_024498.1) was synthesized and cloned by a commercial service (Eurofins) in two fragments: pJET_BoAstV-CH13_Frag A, and pGH_BoAstV-CH13_Frag B. Both fragments were linked by Gibson PCR and cloned into the low copy plasmid pACJR 20 (kindly provided by N. Ruggli, Institute of Virology and Immunology, Mittelhäusern, Switzerland) resulting in the construct pACJR_BoAstV-CH13-#55. The sequence was flanked by a T7 promoter sequence at the 5′ end and a unique SwaI site at the 3′ end.…”