Replication of bovine respiratory syncytial virus in bovine and ovine peripheral blood lymphocytes and monocytes and monocytic cell lines (original) (raw)
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Veterinary Microbiology, 1996
The present study compared the replication of bovine respiratory syncytial virus (BRSV) in bovine and ovine peripheral blood mononuclear cells, ovine and bovine monocytic cell lines and ovine alveolar macrophages. Low titres of virus were detected in ovine and bovine lymphocytes and monocytes 24-96 h post-exposure to the virus but there was no apparent replication of the virus in ovine alveolar macrophages during the culture period. The virus replicated to higher but statistically insignificant titres in ovine and bovine peripheral blood monocytes than in lymphocytes, with lymphocytes yielding peak titres significantly earlier. The secondary cell lines obtained from ovine liver and bone marrow also supported the replication of BRSV to high titres. The titres of BRSV in ovine and bovine lymphocytes and monocytes were significantly lower than in secondary cell lines. The addition of human recombinant tumour necrosis factor alpha after exposure to the virus or pre-incubation of ovine or bovine monocytic cells with either human recombinant interleukin 2 or phorbol myristate acetate before exposure to BRSV, did not significantly affect virus titre. Pre-incubation of cells with indomethacin or actinomycin significantly lowered virus titre (p < 0.05).
Journal of Comparative Pathology, 1998
Bovine respiratory syncytial virus (BRSV) depressed the proliferative reactivity of normal ovine peripheral blood lymphocytes to phytohaemagglutinin (PHA). This BRSV-induced reduction in proliferative reactivity was not reversed or ameliorated by the addition of (1) indomethacin or flunixin rneglurnine, substances known to inhibit the production of prostaglandins, or (2) the cytokines, interleukin-1 (IL-1) and interleukin-2 (IL-2), or (3) rat growth factor. The results suggest that the suppression of ovine lymphocyte reactivity to PHA associated with BRSV was not caused by the release of cyclooxygenase products such as prostaglandins, or the production of inhibitors of IL-1 or IL-2.
Persistent Infection of B Lymphocytes by Bovine Respiratory Syncytial Virus
Virology, 2001
Bovine respiratory syncytial virus (BRSV) is a major cause of respiratory disease in young cattle. Here we demonstrate BRSV persistence at low levels in tracheobronchial and mediastinal lymph nodes up to 71 days after the experimental infection of calves. Positive results were obtained on viral genomic RNA and messenger RNA coding for the nucleoprotein, glycoprotein (G), and fusion protein (F). G and F proteins were also detected in the pulmonary lymph nodes by immunohistochemistry. Double-staining experiments revealed that viral antigen was present in B-lymphocytes. Coculture experiments with the lymph node cells showed that the virus was still able to infect permissive target cells, even though no cytopathic effect was recorded. In vitro studies indicate that BRSV was still able to replicate in bovine B-lymphocyte cell lines 6 months after infection. These results may also be relevant to the understanding not only of the epidemiology and the peculiarities of the immune response of BRSV infections but also of human respiratory syncytial virus infections.
Replication and Clearance of Respiratory Syncytial Virus
The American Journal of Pathology, 2002
Human respiratory syncytial virus is an important cause of severe respiratory disease in young children, the elderly, and in immunocompromised adults. Similarly, bovine respiratory syncytial virus (BRSV) is causing severe, sometimes fatal, respiratory disease in calves. Both viruses are pneumovirus and the infections with human respiratory syncytial virus and BRSV have similar clinical, pathological, and epidemiological characteristics. In this study we used ex-
Immunology of bovine respiratory syncytial virus infection of cattle
Comparative Immunology, Microbiology and Infectious Diseases, 2012
Bovine respiratory syncytial virus (BRSV) is a respiratory pathogen of cattle that causes severe disease in calves alone and as one of several viruses and bacteria that cause bovine respiratory disease complex. Like human RSV this virus modulates the immune response to avoid stimulation of a vibrant CD8+ T cytotoxic cell response and instead promotes a Th2 response. The Th2 skew sometimes results in the production of IgE antibodies and depresses production of the Th1 cytokine interferon ␥. Innate immune cells have a pivotal role in guiding the adaptive response to BRSV, with selective secretion of cytokines by pulmonary dendritic cells. Here we review some of the pertinent observations on immune responses to BRSV infection and vaccination and illustrate how experimental infection models have been used to elucidate the immunopathogenesis of BRSV infection. Recent experiments using intranasal vaccination and/or immune modulation with DNA based adjuvants show promise for effective vaccination by the stimulation of Th1 T cell responses.
Journal of Virology, 2003
Here we demonstrate that, in contrast to wild-type BRSVs, recombinant BRSVs (rBRSVs) lacking the NS proteins, and those lacking NS2 in particular, are strong inducers of IFN-␣/ in bovine nasal fibroblasts and bronchoalveolar macrophages. Furthermore, whereas the NS deletion mutants replicated to wild-type rBRSV levels in cells lacking a functional IFN-␣/ system, their replication was severely attenuated in IFN-competent cells and in young calves. These results suggest that the NS proteins block the induction of IFN-␣/ gene expression and thereby increase the virulence of BRSV. Despite their poor replication in the respiratory tract of young calves, prior infection with virus lacking either the NS1 or the NS2 protein induced serum antibodies and protection against challenge with virulent BRSV. The greater level of protection induced by the NS2, than by the NS1, deletion mutant, was associated with higher BRSV-specific antibody titers and greater priming of BRSV-specific, IFN-␥-producing CD4 ؉ T cells. Since there were no detectable differences in the ability of these mutants to replicate in the bovine respiratory tract, the greater immunogenicity of the NS2 deletion mutant may be associated with the greater ability of this virus to induce IFN-␣/. , 391-2 (31) and 127 (45) strains of BRSV were prepared in fetal calf kidney(FCK) cells as described previously . Wild-type (WT) recombinant BRSV (rBRSV) and viruses lacking either the NS1 gene (⌬NS1), the NS2 gene (⌬NS2), or both (⌬NS1/2) were derived from full-length cDNA of BRSV strain A51908 (36), variant Atue51908 (GenBank accession no. AF092942), as reported previously ). Stocks of rBRSV were prepared in Vero cell monolayers that were infected at a multiplicity of infection (MOI) between 0.1 and 0.5 in Dulbecco's modified Eagle's medium (Gibco-BRL, Paisley, United Kingdom) containing 2% heated fetal calf serum (HFCS), as described previously. All recombinant virus stocks were checked by reverse transcriptase PCR (RT-PCR) for the presence of mRNA for the NS proteins (data not shown), and all virus stocks were free from contamination with bovine viral diarrhea virus.
Acta Veterinaria Brno, 2003
One-step RT-PCR and nested PCR were used to detect bovine respiratory syncytial virus (BRSV) in infected cell cultures. Specific 984 bp and 383 bp products, selected from gene encoding the F protein using suitable primers, were amplified and, if appropriate, reamplified. The method was further used for examination of nasal swabs and blood samples collected from animals showing signs of a respiratory disease. Lactating cows and 6-8-month-old bulls from two herds were investigated. The infection by BRSV was confirmed by a) demonstration of specific fragments of BRSV genome in all animals showing signs of an acute disease, and b) indirectly by serological methods in convalescent animals. Viral RNA was detected from nasal swabs and leukocytes of affected animals. The positive PCR product obtained by nested RT-PCR from RNA isolated from leukocytes was sequenced and nucleotide and amino acid homology were 97-100% and 94.5-100% respectively, when compared with sequences from the GenBank. Considering the difficulties associated with the demonstration of BRSV in cell cultures, the amplification techniques provide an effective tool for the identification of the causative agent of bovine respiratory diseases.