Disease relevance of Porcine respiratory and reproductive syndrome virus

• Porcine reproductive and respiratory syndrome virus (PRRSV) glycoprotein 5 (GP5) is the most abundant envelope glycoprotein and a major inducer of neutralizing antibodies in vivo [1].
• Taken together, our studies demonstrate a specific interaction of the PRRSV nucleocapsid protein with the host cell protein fibrillarin in the nucleolus, and they imply a potential linkage of viral strategies for the modulation of host cell functions, possibly through rRNA precursor processing and ribosome biogenesis [2].
• Virions of porcine reproductive and respiratory syndrome virus (PRRSV) contain six membrane proteins: the major proteins GP5 and M and the minor proteins GP2a, E, GP3, and GP4 [3].
• The Québec reference strain of PRRSV appeared to be related more closely to equine arteritis virus and lactate dehydrogenase-elevating virus than are the two European strains of the virus [4].
• We studied the interferon-alpha (IFN-alpha) system in relation to the porcine arterivirus (PoAV), porcine reproductive and respiratory syndrome virus (PRRSV) [5].

High impact information on Porcine respiratory and reproductive syndrome virus

• Recently, we showed that porcine sialoadhesin (pSn) mediates internalization of the arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) in alveolar macrophages (Vanderheijden et al., J. Virol. 77:8207-8215, 2003) [6].
• Altogether, these results show that sialoadhesin is involved in the entry process of PRRSV in PAM [7].
• In the present study, we show by confocal microscopy that the PRRSV N protein colocalizes with the small nucleolar RNA (snoRNA)-associated protein fibrillarin [2].
• Swine (PK-15) cells resistant to viral entry were transfected with the cloned p210 cDNA and inoculated with European or American PRRSV strains [7].
• Moreover, NEM-resistant disulfide linkages were shown to occur only during productive PRRSV infection, since expression of recombinant N protein did not result in the formation of NEM-resistant disulfide-linked homodimers [8].

Chemical compound and disease context of Porcine respiratory and reproductive syndrome virus

• GP(3), which was identified as a minor structural protein of European types of PRRSV, did not bind to heparin [9].
• Analysis of infection kinetics showed that PRRSV attachment to heparan sulfate occurs early in infection [9].
• Ceftiofur treatment was the only regimen that significantly (P < 0. 05) reduced mortality associated with PRRSV and S. suis coinfection [10].
• RT-PCR was found to be more sensitive than indirect immunofluorescence assay for detection of PRRSV in tissues from experimentally infected pigs and as sensitive as virus isolation in PAM, especially when combined with Southern blotting with the digoxigenin-labeled N probe and chemiluminescence detection [11].
• The data suggest that, in addition to homodimerization, the PRRSV N protein may also undergo heterodimerization with another structural protein using cysteine 90 and that the N protein heterodimerization is essential for PRRSV infectivity [12].

Biological context of Porcine respiratory and reproductive syndrome virus

• The data indicate that cysteine residues in the E protein are not essential for replication of North American genotype PRRSV [13].
• Nucleotide sequence analysis of North American PRRSV isolate SDSU-23983 revealed a small ORF within ORF2, named ORF2b, which, when translated, produced a 73-amino-acid nonglycosylated protein [14].
• An RNA helicase, RHIV -1, induced by porcine reproductive and respiratory syndrome virus (PRRSV) is mapped on porcine chromosome 10q13 [15].
• The hydrophilic carboxyterminal 199 amino acids encoded by the ORF 3 of a European (Lelystad) isolate of PRRSV were expressed as a recombinant fusion protein (BP03-P) in a baculovirus gene expression system [16].
• Comparative sequence analysis indicates that there are degrees of amino acid identity to the Lelystad virus open reading frames ranging from 55% in ORF 5 to 79% in ORF 6 [17].

Anatomical context of Porcine respiratory and reproductive syndrome virus

• PROCEDURES: Plaque assays, using a continuous cell line (MARC-145) derived from African green monkey kidney cell line (MA104), were performed for determination of inhibitory effect of heparin on PRRSV, PRV, and PIV-3 [18].
• Booster immunizations of mixed ORF5 peptides and co-administration of IL-12 with MLV PRRSV vaccine significantly enhanced IFNgamma expression by some T-cell subsets (CD4(-)CD8(+)gammadelta+ and CD4(-)CD8(-)gammadelta+ for mixed ORF5 peptides and CD4(+)CD8(+)gammadelta- and CD4(-)CD8(+)gammadelta+ for IL-12) [19].
• The ability of the digoxigenin-labeled probe to specifically detect PRRSV RNA was tested on cultured cells infected with 6 Canadian PRRSV isolates, a US PRRSV isolate and the European Lelystad isolate [20].
• In general, the newly developed ReTi-PCR tests are valuable tools for the early, reliable and rapid detection of five economically important viruses, namely PRV, CSFV, FMDV, SVDV, and PRRSV in boar semen [21].
• Pigs at 4 months of age were infected with porcine reproductive and respiratory syndrome virus (PRRSV), and peripheral blood monocytes (PBMC) were isolated for the detection of interferon gamma (IFNgamma)-producing cells [22].

Gene context of Porcine respiratory and reproductive syndrome virus

• The dimer interface consists of a continuous four-stranded beta-sheet superposed by two long alpha helices, reminiscent of that found in the nucleocapsid protein of porcine respiratory and reproductive syndrome virus [23].
• Porcine RHIV -1 transcripts were ubiquitously expressed in various pig tissues, while in PRRSV-infected pigs, higher expression was observed in several tissues persistent for PRRSV [15].
• This study implies that the induction of IL-10 production may be one of the strategies used by PRRSV to modulate host immune responses [24].
• Previously we have shown that Lelystad virus (LV) contains five structural proteins, a nucleocapsid protein N, an integral membrane protein M, and three glycoproteins GP3, GP4, and GP5 [25].
• The ORF5-encoded major envelope glycoprotein (GP5) of porcine reproductive and respiratory syndrome virus (PRRSV) is one of the three major structural proteins of this virus [26].

Analytical, diagnostic and therapeutic context of Porcine respiratory and reproductive syndrome virus

• The gene encoding glycoprotein 5 (ORF5) of 21 porcine reproductive and respiratory syndrome virus (PRRSV) isolates from Spain and two European-type vaccines currently available in that country were analysed using RT-PCR and sequencing [27].
• Together, our results show that ORF3 sequencing is a valuable epidemiologic tool for examining the emergence and spread of PRRSV in Europe. As such, the panel of well-characterized and highly divergent ORF3 sequences described in this study provides a reference point for future molecular epidemiologic studies [28].
• Sera from pigs infected with the European porcine reproductive and respiratory syndrome virus (PRRSV), strain Lelystad virus (LV), were screened by indirect ELISA for antibodies that bound to a series of overlapping synthetic peptides covering amino acids (AA) 19-60 of the primary envelope glycoprotein (GP)5 [29].
• Thus, while exogenous addition of IFNA during PRRSV vaccination has an impact on the development of a Th1 immune response, other alterations will be required for substantial boosting of virus-specific protection [30].
• However, when only formalin-fixed tissues are submitted, immunohistochemistry and in situ hybridization would be useful methods for the detection of PRRSV antigen and nucleic acid [31].

References