Browsing by Author "Nauwynck, H. J."
Now showing 1 - 10 of 10
- Results Per Page
- Sort Options
Item Binding and entry characteristics of porcine circovirus 2 in cells of the porcine monocytic line 3D4/31Misinzo, G.; Meerts, P.; Bublot, M.; Mast, J.; Weingartl, H. M.; Nauwynck, H. J.Item Correlation between the presence of neutralizing antibodies against porcine circovirus 2 (PCV2) and protection against replication of the virus and development of PCV2-associated diseaseMeerts, P.; Misinzo, G.; Lefebvre, D.; Nielsen, J.; Bøtner, A.; Kristensen, C. S.; Nauwynck, H. J.Item Correlation between the presence of neutralizing antibodies against porcine circovirus 2 (PCV2) and protection against replication of the virus and development of PCV2-associated disease(2006-01-30) Meerts, P.; Misinzo, G.; Lefebvre, D.; Nielsen, J.; Bøtner, A.; Kristensen, C. S.; Nauwynck, H. J.Background: In a previous study, it was demonstrated that high replication of Porcine circovirus 2 (PCV2) in a gnotobiotic pig was correlated with the absence of PCV2-neutralizing antibodies. The aim of the present study was to investigate if this correlation could also be found in SPF pigs in which PMWS was experimentally reproduced and in naturally PMWS-affected pigs. Results: When looking at the total anti-PCV2 antibody titres, PMWS-affected and healthy animals seroconverted at the same time point, and titres in PMWS-affected animals were only slightly lower compared to those in healthy animals. In healthy animals, the evolution of PCV2-neutralizing antibodies coincided with that of total antibodies. In PMWS-affected animals, neutralizing antibodies could either not be found (sera from field studies) or were detected in low titres between 7 and 14 DPI only (sera from experimentally inoculated SPF pigs). Differences were also found in the evolution of specific antibody isotypes titres against PCV2. In healthy pigs, IgM antibodies persisted until the end of the study, whereas in PMWS-affected pigs they quickly decreased or remained present at low titres. The mean titres of other antibody isotypes (IgG1, IgG2 and IgA), were slightly lower in PMWS-affected pigs compared to their healthy group mates at the end of each study. Conclusion: This study describes important differences in the development of the humoral immune response between pigs that get subclinically infected with PCV2 and pigs that experience a high level of PCV2-replication which in 3 of 4 experiments led to the development of PMWS. These observations may contribute to a better understanding of the pathogenesis of a PCV2- infection.Item Genetic characterization of African swine fever viruses from a 2008 outbreak in TanzaniaMisinzo, G.; Magambo, J.; Masambu, J.; Yongolo, M. G.; Doorsselaere, J. V.; Nauwynck, H. J.Item Genetic characterization of African swine fever viruses from a 2008 outbreak in Tanzania(2011-02) Misinzo, G.; Magambo, J.; Masambu, J.; Yongolo, M. G.; Doorsselaere, J. V.; Nauwynck, H. J.Outbreaks of African swine fever (ASF) have been reported in the past from several countries in sub-Saharan Africa. The aim of this study was to genotype ASF viruses (ASFVs) from the 2008 outbreak in Morogoro and Dar es Salaam regions of Tanzania. Tissue samples from domestic pigs that died as a result of severe haemorrhagic disease were collected and analysed with PCR and genome sequencing methods using ASFV-specific primer sets. Nucleotide sequence data were obtained for the B646L (p72), E183L (p54) and the variable region of the B602L gene sequences. Phylogenetic analyses based on DNA sequences showed that the 2008 Tanzanian isolates belonged to p72 genotype XV and clustered together with those derived from the 2001 outbreak in Tanzania. Analysis of the tetrameric amino acid repeat regions within the variable region of the B602L gene showed that the repeat signature of the 2008 Tanzanian ASFV was unique and contained three novel tetramers (U = NIDT/NTDT and X = NTDI). Epidemiological investigation suggested that transportation of live pigs continues to play an active role in the epidemiology of ASF in Tanzania. It is recommended that future control of ASF spread in Tanzania should focus on the early detection and confirmation of the disease, prompt institution of quarantine measures, culling and proper disposal of infected and in-contact animals and decontamination of affected premises.Item Increased porcine circovirus type 2 replication in porcine leukocytes in vitro and in vivo by concanavalin A stimulation(Veterinary Microbiolog) Lefebvre, D. J.; Meerts, P.; Costers, S.; Misinzo, G.; Barbe, F.; Reeth, K. V.; Nauwynck, H. J.Item Increased porcine circovirus type 2 replication in porcine leukocytes in vitro and in vivo by concanavalin A stimulation(Veterinary Microbiolog, 2008-05-05) Lefebvre, D. J.; Meerts, P.; Costers, S.; Misinzo, G.; Barbe, F.; Reeth, K. V.; Nauwynck, H. J.Previously, it was shown that modulation of the immune system enhances porcine circovirus type 2 (PCV2) replication in pigs. In the present study, the effect of the mitogen concanavalin A (ConA) on PCV2 replication was investigated. Since ConA induces T-lymphocyte activation and initiates the production of interferon-gamma (IFN-g), a cytokine that enhances PCV2 replication in porcine epithelial and monocytic cell lines in vitro, it was examined if the effects observed with ConA were mediated by IFN-g. In an in vitro study, ConA but not IFN-g enhanced PCV2 replication in peripheral blood mononuclear cells (PBMC). Up to 2.08% and 0.96% of PBMC were antigen positive for PCV2 strains 1121 and Stoon-1010, respectively, and a low virus production was observed. PCV2-infected PBMC were identified as CD4+ (40%), CD8+ (54%) and IgM+ (11%). In a subsequent in vivo study, caesarean-derived colostrum-deprived piglets were injected with ConA or IFN-g 12 h before inoculation and every 3 days for 9 days after inoculation with strain 1121. PCV2 was isolated from inguinal lymph node biopsies from 10 days post-inoculation (dpi) in ConA-treated pigs and from 15 dpi in non-treated and IFN-g-treated pigs. ConA increased PCV2 replication levels, but disease was not observed. Half of the ConA-treated and IFN-g-treated pigs showed a delayed humoral immune response, but this delay did not result in increased PCV2 replication in these pigs. These experiments demonstrated that ConA enhances PCV2 replication in PBMC in vitro and in lymphoid tissues in vivo. # 2008 Elsevier B.V. All rights reserved.Item Porcine reproductive and respiratory syndrome virus entry into the porcine macrophage(Journal of General Virology) Breedam, W. V.; Delputte, P. L.; Van Gorp, H.; Misinzo, G.; Vanderheijden, N.; Duan, X.; Nauwynck, H. J.Item Porcine reproductive and respiratory syndrome virus entry into the porcine macrophage(Journal of General Virology, 2010) Breedam, W. V.; Delputte, P. L.; Van Gorp, H.; Misinzo, G.; Vanderheijden, N.; Duan, X.; Nauwynck, H. J.Porcine reproductive and respiratory syndrome virus (PRRSV) emerged in the late 1980s and rapidly became one of the most significant viral pathogens in the swine industry. In vivo, the virus shows a very narrow cell tropism and targets specific subsets of porcine macrophages. The entry of PRRSV into its host cell is the first crucial step in infection and has been the focus of many fundamental studies. This review provides a comprehensive overview of the current knowledge on PRRSV entry into the porcine macrophage, covering virus binding, internalization and genome release, and integrates these findings into a general model of the entry process.Item Replication kinetics of different porcine circovirus 2 strains in PK-15 cells, fetal cardiomyocytes and macrophagesMeerts, P.; Misinzo, G.; McNeilly, F.; Nauwynck, H. J.