scholarly journals Toxoplasma  GRA15 and GRA24 are important activators of the host innate immune response in the absence of TLR11

2020 ◽  
Vol 16 (5) ◽  
pp. e1008586 ◽  
Author(s):  
Debanjan Mukhopadhyay ◽  
David Arranz-Solís ◽  
Jeroen P. J. Saeij
2012 ◽  
Vol 4 ◽  
pp. 405-409 ◽  
Author(s):  
Adrianna Pawlik ◽  
Grażyna Sender ◽  
Rafał Starzyński ◽  
Agnieszka Korwin-Kossakowska

2017 ◽  
Vol 24 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Kong-Hung Sze ◽  
Wai-Hei Lam ◽  
Hongmin Zhang ◽  
Yi-hong Ke ◽  
Man-Kit Tse ◽  
...  

2012 ◽  
Vol 80 (11) ◽  
pp. 3892-3899 ◽  
Author(s):  
Azad Eshghi ◽  
Kristel Lourdault ◽  
Gerald L. Murray ◽  
Thanatchaporn Bartpho ◽  
Rasana W. Sermswan ◽  
...  

ABSTRACTPathogenicLeptospiraspp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. In this study, we characterizedLeptospira interroganscatalase (KatE), the only annotated catalase found within pathogenicLeptospiraspecies, by assessing its role in resistance to H2O2-induced oxidative stress and during infection in hamsters. PathogenicL. interrogansbacteria had a 50-fold-higher survival rate under H2O2-induced oxidative stress than did saprophyticL. biflexabacteria, and this was predominantly catalase dependent. We also characterized KatE, the only annotated catalase found within pathogenicLeptospiraspecies. Catalase assays performed with recombinant KatE confirmed specific catalase activity, while protein fractionation experiments localized KatE to the bacterial periplasmic space. The insertional inactivation ofkatEin pathogenicLeptospirabacteria drastically diminished leptospiral viability in the presence of extracellular H2O2and reduced virulence in an acute-infection model. Combined, these results suggest thatL. interrogansKatE confersin vivoresistance to reactive oxygen species induced by the host innate immune response.


2009 ◽  
Vol 84 (3) ◽  
pp. 1574-1584 ◽  
Author(s):  
Lalit K. Beura ◽  
Saumendra N. Sarkar ◽  
Byungjoon Kwon ◽  
Sakthivel Subramaniam ◽  
Clinton Jones ◽  
...  

ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) infection of swine leads to a serious disease characterized by a delayed and defective adaptive immune response. It is hypothesized that a suboptimal innate immune response is responsible for the disease pathogenesis. In the study presented here we tested this hypothesis and identified several nonstructural proteins (NSPs) with innate immune evasion properties encoded by the PRRS viral genome. Four of the total ten PRRSV NSPs tested were found to have strong to moderate inhibitory effects on beta interferon (IFN-β) promoter activation. The strongest inhibitory effect was exhibited by NSP1 followed by, NSP2, NSP11, and NSP4. We focused on NSP1α and NSP1β (self-cleavage products of NSP1 during virus infection) and NSP11, three NSPs with strong inhibitory activity. All of three proteins, when expressed stably in cell lines, strongly inhibited double-stranded RNA (dsRNA) signaling pathways. NSP1β was found to inhibit both IFN regulatory factor 3 (IRF3)- and NF-κB-dependent gene induction by dsRNA and Sendai virus. Mechanistically, the dsRNA-induced phosphorylation and nuclear translocation of IRF3 were strongly inhibited by NSP1β. Moreover, when tested in a porcine myelomonocytic cell line, NSP1β inhibited Sendai virus-mediated activation of porcine IFN-β promoter activity. We propose that this NSP1β-mediated subversion of the host innate immune response plays an important role in PRRSV pathogenesis.


2013 ◽  
Vol 94 (11) ◽  
pp. 2367-2392 ◽  
Author(s):  
Geoffrey L. Smith ◽  
Camilla T. O. Benfield ◽  
Carlos Maluquer de Motes ◽  
Michela Mazzon ◽  
Stuart W. J. Ember ◽  
...  

Virus infection of mammalian cells is sensed by pattern recognition receptors and leads to an innate immune response that restricts virus replication and induces adaptive immunity. In response, viruses have evolved many countermeasures that enable them to replicate and be transmitted to new hosts, despite the host innate immune response. Poxviruses, such as vaccinia virus (VACV), have large DNA genomes and encode many proteins that are dedicated to host immune evasion. Some of these proteins are secreted from the infected cell, where they bind and neutralize complement factors, interferons, cytokines and chemokines. Other VACV proteins function inside cells to inhibit apoptosis or signalling pathways that lead to the production of interferons and pro-inflammatory cytokines and chemokines. In this review, these VACV immunomodulatory proteins are described and the potential to create more immunogenic VACV strains by manipulation of the gene encoding these proteins is discussed.


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