Download or read book Immune Evasion Mechanisms of the Porcine Reproductive and Respiratory Syndrome Virus written by Romeo E. Sanchez (Jr.) and published by . This book was released on 1999 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanisms of Porcine Reproductive and Respiratory Syndrome Virus PRRSV Control of the Host Innate Immune Response written by Christopher Overend and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Pathogenic Mechanisms of Porcine Reproductive and Respiratory Syndrome Virus written by Rui Guo and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Porcine reproductive and respiratory syndrome virus (PRRSV) causes a tremendous economic loss in swine industry worldwide. The capabilities to evade host immune responses and to establish persistent infection are the two hallmark features of PRRSV infection. In this dissertation, the research was mainly focused on investigating the novel mechanisms underlying PRRSV transmission and persistence. In chapter 2, the research was focused on an alternative pathway of PRRSV intercellular transmission. Our data showed that intercellular nanotube connections can be utilized for cell-to-cell spreading the core infectious viral machinery (viral RNA, certain replicases and structural proteins) of PRRSV. Live-cell movies tracked the intercellular transport of a recombinant PRRSV that expressed green fluorescent protein (GFP)-tagged nsp2 in a receptor-independent manner. The cytoskeleton proteins F-actin and myosin-IIA were identified as co-precipitates with PRRSV nanotube associated proteins. Drugs inhibiting actin polymerization or myosin-IIA activation prevented nanotube formations and viral clusters in virus-infected cells. These data lead us to propose that PRRSV utilizes the host cell cytoskeletal machinery inside nanotubes for efficient cell-to-cell spread. This form of virus transport represents an alternative pathway for virus spread, which is resistant to the host humoral immune response. In chapter 3, we further showed that PRRSV infection could induce the formation of nanotubes between infected and uninfected cells following a ROS-dependent nanotube formation model. Co-culturing PRRSV-infected cells with uninfected cells rescued PRRSV-induced cell death. Mitochondrion was observed transferring from uninfected to PRRSV-infected cells. Importantly, impaired formation of nanotube or defective mitochondrion was unable to rescue infected cells from apoptosis/necrosis. Certain PRRSV proteins were detected to associate with mitochondria and transport from infected to uninfected cells through TNTs. Our results suggest that TNTs-transfer of functional mitochondria rescued PRRSV-infected cells from apoptosis/necrosis in the early stage of infection. On the other hand, mitochondria could be utilized as a cargo to transport viral materials for spreading the infection. In chapter 4, a novel mechanism s of PRRSV persistent infection has been studied. In this study, a cellular model of persistent infection was established. Strand-specific quantitative RT-PCR and RNase I treatment analysis showed that double-stranded RNA (dsRNA) conformation existed in persistently infected cells. This data has been further confirmed in vivo by performing two independent PRRSV persistence studies. Immunohistochemistry analysis showed that viral dsRNAs were detected aggregating inside the germinal centers of tonsils and lymph nodes from PRRSV persistence pigs, but RNA array analysis further showed that dsRNA in lymphoid tissues had limited ability to stimulate host antiviral responses during persistent infection stage. These results suggest that the PRRSV dsRNA functions as a mediator for viral persistence. The viral dsRNA persistence in germinal centers of lymphoid tissues may reveal a novel mechanism for PRRSV to escape antiviral immune responses. In summary, this study investigated two novel pathogenic mechanisms of PRRSV infection, which could provide insights on the development of effective control strategies.

Download or read book Pathogenic mechanism of porcine viral disease written by Mengmeng Zhao and published by Frontiers Media SA. This book was released on 2024-09-30 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Swine virus diseases pose a significant threat to the pig industry due to their highly contagious nature and ability to cause immense harm. Once a pig is infected, the risk extends to the entire farm or even a larger area. In recent years, there has been an emergence and re-emergence of disease pathogens that have been able to overcome existing immune defense mechanisms through continuous recombination and evolution. As a result, current immune prevention and control measures have become ineffective. Notable examples of these diseases include African swine fever virus (ASFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV), and porcine pseudorabies virus (PRV). These viruses constantly mutate under various selection pressures, including immunity within the host body and vaccine-induced immunity. Furthermore, with the increase in international trade, the spread of these viruses has become more rapid and extensive. Moreover, it is worth noting that similar virus strains originating from different regions have the potential to undergo recombination, resulting in the emergence of recombinant mutant strains. These mutant strains can pose a challenge to existing immune prevention and control measures, thereby adding complexity to the ongoing efforts in disease prevention and control.

Download or read book Mechanisms of Control of Porcine Reproductive and Respiratory Syndrome Virus PRRSV Infection in Pigs written by Zhengguo Xiao and published by . This book was released on 2004 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Mechanisms of Porcine Reproductive and Respiratory Syndrome Virus Nonstructural Protein 2 in Host Innate Immunity written by Zhi Sun and published by . This book was released on 2012 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Porcine Reproductive and Respiratory Syndrome Virus Infection of Immune privileged Sites written by Jinho Shin and published by . This book was released on 1999 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cross reactive Immunity to Porcine Reproductive and Respiratory Syndrome Virus and Its Contribution to Protection written by Ignacio Correas and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the vast geographical distribution and significant economic losses generated, porcine reproductive and respiratory syndrome virus (PRRSV) can be considered the most important swine pathogen of contemporary times. Current control and eradication strategies against PRRSV have difficulty succeeding because of their complex nature and the absence of an effective vaccine. A major obstacle for PRRSV vaccine development is the broad heterogeneity of the virus, both at the genetic and antigenic level, its rapid evolution, and an incomplete knowledge of the immune responses responsible for clearing the virus from the host. Specifically, how known correlates of protection against PRRSV---neutralizing antibodies and T cells---cross-react with heterologous isolates and mediate cross-protection is inadequately understood. The objectives of this dissertation were (i) to determine the extent of cross-reactivity of immune responses against PRRSV, and (ii) to ascertain how cross-reactive immune responses mediate protection against heterologous isolates. T cell responses were found to be cross-reactive among PRRSV-2 isolates, but extremely variable among individual animals, while the neutralizing antibody response induced by a single infection with PRRSV was deemed to be solely self-neutralizing. Sequential exposure to heterologous PRRSV-2 isolates elicited neutralizing antibodies to the isolates used for infection and challenge, as well as other heterologous PRRSV-2 isolates. Furthermore, prior exposure to PRRSV afforded cross-protection against heterologous challenge, with reduction in viremia, tissue viral load and the extent of microscopic lung lesions; however, protection was still suboptimal. T cell cross-reactivity between PRRSV-1 and PRRSV-2 was evaluated at the structural protein level and was deemed to be feeble or absent. Prior exposure to PRRSV-1 did not prime the T cell response against the PRRSV-2 structural proteins after PRRSV-2 challenge. Collectively, the results in this dissertation contribute to furthering the understanding of immune responses against PRRSV and may be used in the development of a better vaccine.

Download or read book Cell mediated Immunity to Porcine Reproductive and Respiratory Syndrome Virus in Swine written by Elida Margoth Bautista and published by . This book was released on 1998 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Immune Response of Swine to Porcine Reproductive and Respiratory Syndrome Virus Laboratory and Field Studies written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions of Porcine Reproductive and Respiratory Syndrome Virus with Innate Immune Responses written by Sang-Myeong Lee and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: North American field isolates of PRRSV differed in their type I IFN response with respect to induction, sensitivity and suppression. Furthermore, one PRRSV isolate strongly enhanced polyI:C - induced IFN-[alpha] production in PAM cultures and this priming effect was suppressed by other PRRSV isolates. PRRSV activates NF-[kappa]B which is a critical regulator of innate and adaptive immune function. NF-[kappa]B activation was dependent on virus replication and I[kappa]B[alpha] degradation. ROS production was involved in NF-[kappa]B activation by PRRSV. NF-[kappa]B dependent expression of MMP-2 and MMP-9 suggested a possible role of the NF-[kappa]B pathway in PRRSV pathogenesis and the immune response. PRRSV infection induced both intrinsic and extrinsic apoptosis pathways and linked these two pathways via Bid cleavage by caspase-8. While apoptosis was significantly suppressed by caspase inhibitors, the same inhibitors did not affect PRRSV replication. This study also provided evidence of a possible involvement of NF-[kappa]B and ROS in apoptosis induced by PRRSV.

Download or read book Evaluation of Immune Management Strategies to Control and Eliminate Porcine Reproductive and Respiratory Syndrome Virus PRRSv written by Daniel Correia Lima Linhares and published by . This book was released on 2012 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterizing the Porcine Adaptive Immune Response to Homologous Heterologous Porcine Reproductive and Respiratory Syndrome Virus Type 2 PRRSV 2 Strains written by Andrew Robert Kick and published by . This book was released on 2020 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cell mediated Immune Response to Porcine Reproductive and Respiratory Syndrome Virus written by Wasin Charerntantanakul and published by . This book was released on 2006 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cell-mediated immune (CMI) response of pigs to porcine reproductive and respiratory syndrome virus (PRRSV) is low in magnitude and appears late after infection. The ability of PRRSV to suppress CMI response is not known. We reported in this dissertation that PRRSV has the ability to significantly suppress CD25, interferon gamma (IFN[Gamma]), and tumor-necrosis factor alpha expression by T cells in response to concanavalin A and phorbol 12-myristate 13-acetate plus ionomycin, respectively. The suppressive ability of PRRSV associated with PRRSV virulence and type of myeloid antigen-presenting cells the virus infect. Virulent PRRSV significantly suppressed T cell response, whereas attenuated PRRSV did not. Monocytes supported T cell suppression more effectively than monocyte-derived macrophages and immature monocyte-derived dendritic cells. T cell suppression negatively associated with increased interleukin-10 (IL-10) gene expression. Neutralization of IL-10 activity by anti-swine IL-10 monoclonal antibodies inhibited T cell suppression. PRRSV modified-live virus (MLV) vaccine is currently used in the field to control diseases caused by PRRSV. To enhance CMI response to PRRSV MLV vaccine, five different vaccine adjuvants (bacterial endotoxin-derived adjuvant, mixed open reading frame 5 (ORF5) peptides derived from 5 PRRSV isolates, porcine IFN[Alpha], polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose, and porcine IL-12) were studied. Administration of mixed 0RF5 peptides at 14 and 28 days after PRRS MLV vaccination significantly increased IFN[Gamma] production in CD4−CD8+[Gamma Delta]+, CD4−CD8+[Gamma Delta]+, and CD4−CD8+[Gamma Delta]− T cells. Administration of porcine IL-12 at 1 day after PRRS MLV vaccination significantly increased IFN[Gamma] production in CD4+CD8+[Gamma Delta]−, CD4−CD8+[Gamma Delta]+, and CD4−CD8+[Gamma Delta]− T cells. Significantly increased IFN[Gamma] expression in CD4+CD8+[Gamma Delta]−, CD4−CD8+[Gamma Delta]+, and CD4−CD8+[Gamma Delta]− T cells but not CD4−CD8+[Gamma Delta]+ T cells were correlated significantly with the reduction of lung lesion scores and viremia after virulent PRRSV challenge. Administration of porcine IFN[Alpha] at -1, 0, and 1 day and porcine IL-12 at 1 day after PRRS MLV vaccination significantly increased CD25 expression in CD4−CD8+[Gamma Delta]+ T cells. However, the increased CD25 expression did not correlate with protection. None of the vaccine adjuvants contributed to the reduction of lung lesion scores and viremia in comparison to PRRS MLV alone.

Download or read book Innate Immune Modulation and Pathogenic Basis for Porcine Reproductive and Respiratory Syndrome Virus written by Hanzhong Ke and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymicrobial Diseases written by Kim A. Brogden and published by . This book was released on 2002 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymicrobial diseases, those involving more than one etiologic agent, are more common than is generally realized and include respiratory diseases, gastroenteritis, conjunctivitis, keratitis, hepatitis, periodontal diseases, multiple sclerosis, genital infections, intra -- abdominal infections, and pertussis.

Download or read book Molecular Basis of Porcine Reproductive and Respiratory Syndrome Virus mediated Innate Immune Suppression written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: