Early interaction of feline calicivirus with cells in culture

http://www.worldcat.org/oclc/2831418

Porcine reproductive and respiratory syndrome virus infection of cells: characterization of the early stages of virus infection and the major structural proteins of the virus

Porcine reproductive and respiratory syndrome (PRRS) is one of the major causes of economic losses to swine producers. The causative agent, the PRRS virus (PRRSV), has been tentatively classified as an arterivirus. PRRSV infect swine alveolar macrophages and induce persistent infection. In vitro, PRRSV replication is restricted to few continuous cell lines, none of which of porcine origin. The interaction of PRRSV with cells and the major structural proteins of the virus have been investigated in these studies, aiming to better understand the mechanisms governing cell tropism and replication in cells;Several cells were used to determine the mechanism of resistance to infection. PRRSV replication was restricted at several distinct steps: first, in most cases, resistance correlated with absence of viral receptors on target cells; second, Vero cells were found defective in virus uncoating; third, a mechanism following virus entry might inhibit virus replication because transfection of cells with viral RNA did not induce progeny virus in all cells tested;The mechanism of virus uptake into MARC-145 cells was also investigated. By analyzing the effect of lysosomotropic drugs on PRRSV infection of cells and electron microscopic analysis of cell-bound viruses, it was determined that PRRSV entered cells by a microfilament-dependent, receptor-mediated endocytic mechanism and that a low pH step was required during the initial stages of infection;The major structural proteins of PRRSV (E, M, and N) were cloned and expressed in a baculovirus system, in an attempt to identify the viral protein(s) that mediated binding to cell. None of the recombinant proteins bound to mammalian cells by using several binding assays. Nonetheless, these proteins were used to induce polyclonal sera that were used to detect the proteins in mammalian cells following virus infection. Using IFA staining of cells, proteins E and M were found circumscribing the cellular nucleus, whereas the N protein was located throughout the cellular cytoplasm;In conclusion, there are multiple mechanisms that might restrict PRRSV replication in cells. However, following binding to permissive cells, PRRSV enters through the endocytic pathway and, during the replication process, the major viral structural proteins accumulate at specific cellular compartments

Fármacos com potencial terapêutico para tratamento da COVID-19 / Drugs with therapeutic potential for COVID-19 treatment

Objetivos: analisar o potencial terapêutico de fármacos para o manejo da infecção por SARS-CoV-2. Métodos: trata-se de uma revisão bibliográfica realizada em base de dados a respeito dos fármacos utilizados para o manejo do SARS-CoV-2. Resultados: os anti-inflamatórios não-esteroidais (AINES) não mostraram evidências positivas ou negativas, no entanto a administração de corticosteroides mostrou potencial terapêutico promissor quando no estágio avançado da infecção e em déficit respiratório. A transfusão de plasma convalescente e o histórico de imunização com BCG apresentaram-se promissores. Os anticoagulantes podem ser utilizados na tentativa de amenizar a coagulopatia induzida quando em caso de sepse e atividade inflamatória exacerbada. Alguns antiparasitários com efeito antiviral já estabelecido mostraram-se sinérgicos a outras classes farmacológicas. Até o momento os dados científicos mostram a tendência de que os antivirais são mais promissores para o tratamento da COVID-19 que as aminoquinolinas. Conclusão: não há evidências científicas definitivas para o uso de fármacos no tratamento da infecção por SARS-CoV-2. Por outro lado, classes farmacológicas como corticoides, anticoagulantes, antiparasitários e antivirais, demonstraram possíveis benefícios no tratamento da COVID-19. Tais resultados precisam ser melhores compreendidos a partir de novos estudos para entender sua real utilidade nos pacientes com SARS-CoV-2

Differences in Haemophilus parasuis adherence to and invasion of AOC-45 porcine aorta endothelial cells

8 p.Background: The pathogenesis of Haemophilus parasuis depends on the bacterium’s ability to interact with endothelial cells and invade adjacent tissues. In this study, we investigated the abilities of eight H. parasuis reference strains belonging to serovars 1, 2, 4, 5, 7, 9, 10 and 13 to adhere to and invade porcine aortic endothelial cells (AOC-45 cell line). Results: The strains belonging to serovars 1, 2 and 5 were able to attach at high rates between 60 and 240 min of incubation, and serovars 4, 7 and 13 had moderate attachment rates; however, the strains belonging to serovars 9 and 10 had low adherence at all time points. Strong adherence was observed by scanning electron microscopy for the strains of serovars 5 and 4, which had high and moderate numbers, respectively, of H. parasuis cells attached to AOC-45 cells after 240 min of incubation. The highest invasiveness was reached at 180 min by the serovar 4 strain, followed by the serovar 5 strain at 240 min. The invasion results differed substantially depending on the strain. Conclusion: The reference strains of H. parasuis serovars 1, 2, 4 and 5 exhibited high adhesion and invasion levels to AOC-45 porcine aorta endothelial cells, and these findings could aid to better explain the pathogenesis of the disease caused by these serovars.S

Bovine leukemia viral DNA found on human breast tissue is genetically related to the cattle virus

Bovine leukemia virus (BLV) infection is widespread in cattle and associated with B cell lymphoma. In a previousstudy we demonstrated that bovine leukemia viral DNA was detected in human breast tissues and significantly associated with breast cancer. Our current study aimed to determine whether BLV DNA found in humans and cattle at the same geographical region were genetically related. DNA was extracted from the breast tissue of healthy (n = 32) or cancerous women patients (n = 27) and from the blood (n = 30) of cattle naturally infected with BLV, followed by PCR-amplification and partial nucleotide sequencing of the BLV env gene. We found that the nucleotide sequence identity between BLV env gene fragments obtained from human breast tissue and cattle blood ranged from 97.8 to 99.7% and grouped into genotype 1. Thus, our results further support the hypothesis that this virus might cause a zoonotic infection

Antimicrobial susceptibility patterns of Brazilian Haemophilus parasuis field isolates

12 p.Haemophilus parasuis is the etiological agent of Glässer’s disease (GD), an ubiquitous infection of swine characterized by systemic fibrinous polyserositis, polyarthritis and meningitis. Intensive use of antimicrobial agents in swine husbandries during the last years triggered the development of antibiotic resistances in bacterial pathogens. Thus, regular susceptibility testing is crucial to ensure efficacy of different antimicrobial agents to this porcine pathogen. In this study, 50 clinical isolates from South Brazilian pig herds were characterized and analyzed for their susceptibility to commonly used antibiotic. The identification and typing of clinical isolates was carried out by a modified indirect hemagglutination assay combined with a multiplex PCR. The susceptibility of each isolate was analyzed by broth microdilution method against a panel of antimicrobial compounds. We found that field isolates are highly resistance to gentamycin, bacitracin, lincomycin and tiamulin, but sensitive to ampicillin, clindamycin, neomycin, penicillin, danofloxacin and enrofloxacin. Furthermore, an individual susceptibility analysis indicated that enrofloxacin is effective to treat clinical isolates with the exception of those classified as serovarS

TbpBY167A-Based Vaccine Can Protect Pigs against Glässer’s Disease Triggered by Glaesserella parasuis SV7 Expressing TbpB Cluster I

Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).[EN] Glaesserella parasuis is the etiological agent of Glässer’s disease (GD), one of the most important diseases afflicting pigs in the nursery phase. We analyzed the genetic and immunological properties of the TbpB protein naturally expressed by 27 different clinical isolates of G. parasuis that were typed as serovar 7 and isolated from pigs suffering from GD. All the strains were classified as virulent by LS-PCR. The phylogenetic analyses demonstrated high similarity within the amino acid sequence of TbpB from 24 clinical strains all belonging to cluster III of TbpB, as does the protective antigen TbpBY167A. Three G. parasuis isolates expressed cluster I TbpBs, indicating antigenic diversity within the SV7 group of G. parasuis. The antigenic analysis demonstrated the presence of common epitopes on all variants of the TbpB protein, which could be recognized by an in vitro analysis using pig IgG induced by a TbpBY167A-based vaccine. The proof of concept of the complete cross-protection between clusters I and III was performed in SPF pigs immunized with the TbpBY167A-based vaccine (cluster III) and challenged with G. parasuis SV7, strains LM 360.18 (cluster I). Additionally, pigs immunized with a whole-cell inactivated vaccine based on G. parasuis SV5 (Nagasaki strain) did not survive the challenge performed with SV7 (strain 360.18), demonstrating the absence of cross-protection between these two serovars. Based on these results, we propose that a properly formulated TbpBY167A-based vaccine may elicit a protective antibody response against all strains of G. parasuis SV7, despite TbpB antigenic diversity, and this might be extrapolated to other serovars. This result highlights the promising use of the TbpBY167A antigen in a future commercial vaccine for GD prevention.SIThis research was funded by Secretaria de Desenvolvimento Econômico Ciência e Tecnologia do Rio Grande do Sul (SDECT, Grant 328–2500/14-0). S.R.P. was supported by Foundation of University of Passo Fundo Master fellowship. S.C. was supported by University of Calgary Eyes High Doctoral Recruitment Award.We thank AFK Imunotech for the generous gift of pigs for this stud

Altered indirect hemagglutination method for easy serotyping of Haemophilus parasuis

P. 15-21Glässer’s disease is an emergent bacterial disease that affects swine husbandries worldwide causing important economic losses. The aetiological agent, Haemophilus parasuis, is currently divided in fifteen serovars but an increasing number of non-typeable serovars have been reported. Indirect hemagglutination (IHA) is indicated as a serotyping method for H. parasuis. In the present study, we describe an additional step that aims to work around a possible obstacle in the original protocol that may compromise the outcome of this assay. We observed that the choice of anticoagulant for blood collection influences and/or impairs spontaneous adsorption of H. parasuis antigens on sheep red blood cells (SRBCs). However, regardless of the anticoagulant used, chemical treatment of SRBCs with tannic acid induces a stable antigen adsorption (sensitization step). The addition of 1% BSA to SRBCs washing buffer and to antisera dilution augments IHA specificity. Tannic acid treated SRBCs combined with thermo-resistant H. parasuis antigens increases the assay resolution. Thus, our results demonstrate an improvement in the technique of H. parasuis serotyping that will prove valuable to understand Glässer’s disease epidemiology and to better characterize serovars involved in outbreaksS

Molecular serotyping of clinical strains of Haemophilus (Glaesserella) parasuis brings new insights regarding Glässer’s disease outbreaks in Brazil

[EN]Glässer's disease (GD) is an important infectious disease of swine caused by Haemophilus (Glaesserella) parasuis. Vaccination with inactivated whole cell vaccines is the major approach for prevention of H. parasuis infection worldwide, but the immunity induced is predominantly against the specific polysaccharide capsule. As a consequence, the available vaccines may not induce adequate protection against the field strains, when the capsules present in the vaccine strains are different from those in strains isolated from the farms. Therefore, it is crucial to map H. parasuis serovars associated with regional outbreaks so that appropriate bacterin vaccines can be developed and distributed for prevention of infection. In this study, 459 H. parasuis field strains isolated from different Glässer's disease outbreaks that occurred in 10 different Brazilian States were analyzed for serotype using PCR-based approaches. Surprisingly, non-Typeable (NT) strains were the second most prevalent group of field strains and along with serovars 4, 5 and 1 comprised more than 70% of the isolates. A PCRbased approach designed to amplify the entire polysaccharide capsule locus revealed 9 different band patterns in the NT strains, and 75% of the NT strains belonged to three clusters, suggesting that a number of new serovars are responsible for a substantial proportion of disease. These results indicate that commercially available vaccines in Brazil do not cover the most prevalent H. parasuis serovars associated with GD.SIThis study was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant 485807/2013-0) and by the Secretaria de Desenvolvimento Econômico Ciência e Tecnologia do Rio Grande do Sul (SDECT, grant 328-2500/14-0). Julia Pires Espíndola and Letícia Trevisan Gressler were supported by Coordenação de Aperfeiçoamento de Pessoal de Ensino Superior (CAPES) Master and Postdoctoral fellowship, respectively. Natalia Balbinott was supported by a CNPq undergraduate fellowship. Luiz Carlos Kreutz has a CNPq PQ fellowship (307900/2016-9). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

New insights about functional and cross-reactive properties of antibodies generated against recombinant TbpBs of Haemophilus parasuis

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Te images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.[EN] Vaccines have become fundamental in the control and elimination of Glässer Disease, a systemic disease of pigs caused by Haemophilus parasuis. The classic vaccines available for prevention of this infection were developed without a robust knowledge about host immunological mechanisms. In this study, we demonstrated the presence of cross-reactive epitopes on both the N-lobe and C-lobe of variants of transferrin binding protein B (TbpBs) expressed on the surface of 6 virulent serovars of H. parasuis. Antibodies against TbpB-derived antigens were capable of increasing the phagocytic capacity of neutrophils and were also capable of blocking porcine transferrin from binding to TbpB. Surprisingly, none of the pig or mice antisera from animals immunized with TbpB-derived antigens mixed with Montanide IMS 2215 VG PR adjuvant were able to activate the classical complement pathway (CCP). In contrast, antisera from mice immunized with TbpB-derived antigens adjuvanted with Freund's adjuvants or Montanide Gel 01 were able to activate the CCP and kill H. parasuis. Our results demonstrate that the type of adjuvant can modulate the functional response induced by TbpB-derived antigens. Based on these results, we propose that a properly formulated TbpB-based vaccine may elicit a functional protective antibody response with broad cross-reactivity against heterologous strains of H. parasuis.SIThis work was supported by the Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq, grant 485807/2013-0) and by the Spanish Ministry of Economy and Competitivity (grant AGL2011-23195). B.B. and J.G. were supported by a Master fellowship from the Fundação Universidade de Passo Fundo and from the Coordenação de Aperfeiçoamento de Pessoal de Ensino Superior (CAPES), respectively. We would also like to thank Dra. Letícia Gressler for technical assistance in the complement system assays