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1.
J Virol ; 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996435

RESUMO

Argentine hemorrhagic fever is a potentially lethal disease that is caused by Junin virus (JUNV). There are currently around 5 million individuals at risk of infection within endemic regions in Argentina. The live attenuated vaccine strain, Candid #1 (Can), is approved for use in endemic regions and has substantially decreased the number of annual Argentine hemorrhagic fever (AHF) cases. The glycoprotein (GPC) gene is primarily responsible for the attenuation of the Can strain, and we have shown that the absence of an N-linked glycosylation motif in the subunit G1 of the GP complex of Can, which is otherwise present in the wild type pathogenic JUNV, causes GPC retention in the ER. Here, we show that Can GPC aggregates in the ER of infected cells, forming incorrect cross-chain disulfide bonds, which results in impaired GPC processing into G1 and G2. The GPC fails to cleave into its G1 and G2 subunits and is targeted for degradation within lysosomes. Cells infected with the wild-type Romero (Rom) strain do not produce aggregates that are observed in Can infection, and the stress on the ER remains minimal. While the mutation of the N-linked glycosylation motif (T168A) is primarily responsible for the formation of aggregates, other mutations within G1 that occurred earlier in the passage history of the Can strain also contribute to aggregation of the GPC within the ER.ImportanceThe development of vaccines and therapeutics to combat viral hemorrhagic fevers remains a top priority within the Implementation Plan of the U.S. Department of Health and Human Services Public Health Emergency Medical Countermeasures Enterprise. The Can strain, derived from the pathogenic XJ strain of JUNV, has been demonstrated to be both safe and protective against AHF. While the vaccine strain is approved for use in endemic regions within Argentina, the mechanisms of Can attenuation have not been elucidated. A better understanding of the viral genetic determinants of attenuation will improve our understanding of the mechanisms contributing to disease pathogenesis and provide critical information for the rational design of live attenuated vaccine candidates for other viral hemorrhagic fevers.

2.
J Virol ; 94(7)2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-31941776

RESUMO

Influenza A (IAV) and influenza B (IBV) viruses are highly contagious pathogens that cause fatal respiratory disease every year, with high economic impact. In addition, IAV can cause pandemic infections with great consequences when new viruses are introduced into humans. In this study, we evaluated 10 previously described compounds with antiviral activity against mammarenaviruses for their ability to inhibit IAV infection using our recently described bireporter influenza A/Puerto Rico/8/34 (PR8) H1N1 (BIRFLU). Among the 10 tested compounds, eight (antimycin A [AmA], brequinar [BRQ], 6-azauridine, azaribine, pyrazofurin [PF], AVN-944, mycophenolate mofetil [MMF], and mycophenolic acid [MPA]), but not obatoclax or Osu-03012, showed potent anti-influenza virus activity under posttreatment conditions [median 50% effective concentration (EC50) = 3.80 nM to 1.73 µM; selective index SI for 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, >28.90 to 13,157.89]. AmA, 6-azauridine, azaribine, and PF also showed potent inhibitory effect in pretreatment (EC50 = 0.14 µM to 0.55 µM; SI-MTT = 70.12 to >357.14) or cotreatment (EC50 = 34.69 nM to 7.52 µM; SI-MTT = 5.24 to > 1,441.33) settings. All of the compounds tested inhibited viral genome replication and gene transcription, and none of them affected host cellular RNA polymerase II activities. The antiviral activity of the eight identified compounds against BIRFLU was further confirmed with seasonal IAVs (A/California/04/2009 H1N1 and A/Wyoming/3/2003 H3N2) and an IBV (B/Brisbane/60/2008, Victoria lineage), demonstrating their broad-spectrum prophylactic and therapeutic activity against currently circulating influenza viruses in humans. Together, our results identified a new set of antiviral compounds for the potential treatment of influenza viral infections.IMPORTANCE Influenza viruses are highly contagious pathogens and are a major threat to human health. Vaccination remains the most effective tool to protect humans against influenza infection. However, vaccination does not always guarantee complete protection against drifted or, more noticeably, shifted influenza viruses. Although U.S. Food and Drug Administration (FDA) drugs are approved for the treatment of influenza infections, influenza viruses resistant to current FDA antivirals have been reported and continue to emerge. Therefore, there is an urgent need to find novel antivirals for the treatment of influenza viral infections in humans, a search that could be expedited by repurposing currently approved drugs. In this study, we assessed the influenza antiviral activity of 10 compounds previously shown to inhibit mammarenavirus infection. Among them, eight drugs showed antiviral activities, providing a new battery of drugs that could be used for the treatment of influenza infections.

4.
Antiviral Res ; 173: 104667, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31786250

RESUMO

The mammarenavirus Lassa (LASV) is highly prevalent in West Africa where it infects several hundred thousand individuals annually resulting in a high number of Lassa fever (LF) cases, a febrile disease associated with high morbidity and significant mortality. Mounting evidence indicates that the worldwide-distributed prototypic mammarenavirus lymphocytic choriomeningitis virus (LCMV) is a neglected human pathogen of clinical significance. There are not Food and Drug Administration (FDA) licensed vaccines and current anti-mammarenavirus therapy is limited to an off-label use of ribavirin that is only partially effective and can cause significant side effects. Therefore, there is an unmet need for novel antiviral drugs to combat LASV. This task would be facilitated by the implementation of high throughput screens (HTS) to identify inhibitors of the activity of the virus ribonucleoprotein (vRNP) responsible for directing virus RNA genome replication and gene transcription. The use of live LASV for this purpose is jeopardized by the requirement of biosafety level 4 (BSL4) containment. We have developed a virus-free cell platform, where expression levels of reporter genes serve as accurate surrogates of vRNP activity, to develop cell-based assays compatible with HTS to identify inhibitors of LASV and LCMV mammarenavirus vRNP activities.

5.
Lancet Infect Dis ; 19(12): 1276-1277, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31588043
6.
DNA Cell Biol ; 38(11): 1170-1177, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502877

RESUMO

Host response to viral infection is a highly regulated process involving engagement of various host factors, cytokines, chemokines, and stimulatory signals that pave the way for an antiviral immune response. The response is manifested in terms of viral sequestration, phagocytosis, and inhibition of genome replication, and, finally, if required, lymphocyte-mediated clearance of virally infected cells. During this process, cross-talk between viral and host factors can shape disease outcomes and immunopathology. Bone marrow stromal antigen 2 (BST-2), also know as tetherin, is induced by type I interferon produced in response to viral infections, as well as in certain cancers. BST-2 has been shown to be a host restriction factor of virus multiplication through its ability to physically tether budding virions and restrict viral spread. However, BST-2 has other roles in the host antiviral response. This review focuses on the diverse functions of BST-2 and its downstream signaling pathways in regulating host immune responses.


Assuntos
Antígenos CD/fisiologia , Imunomodulação/genética , Vírion/imunologia , Vírion/metabolismo , Imunidade Adaptativa/genética , Animais , Antígenos CD/genética , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/fisiologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunomodulação/imunologia , Viroses/genética , Viroses/imunologia
7.
Antiviral Res ; 169: 104558, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31302150

RESUMO

Several mammarenaviruses, chiefly Lassa virus (LASV) in Western Africa and Junín virus (JUNV) in the Argentine Pampas, cause severe disease in humans and pose important public health problems in their endemic regions. Moreover, mounting evidence indicates that the worldwide-distributed mammarenavirus lymphocytic choriomeningitis virus (LCMV) is a neglected human pathogen of clinical significance. The lack of licensed mammarenavirus vaccines and partial efficacy of current anti-mammarenavirus therapy limited to an off-label use of the nucleoside analog ribavirin underscore an unmet need for novel therapeutics to combat human pathogenic mammarenavirus infections. This task can be facilitated by the implementation of "drug repurposing" strategies to reduce the time and resources required to advance identified antiviral drug candidates into the clinic. We screened a drug repurposing library of 11,968 compounds (Repurposing, Focused Rescue and Accelerated Medchem [ReFRAME]) and identified several potent inhibitors of LCMV multiplication that had also strong anti-viral activity against LASV and JUNV. Our findings indicate that enzymes of the rate-limiting steps of pyrimidine and purine biosynthesis, the pro-viral MCL1 apoptosis regulator, BCL2 family member protein and the mitochondrial electron transport complex III, play critical roles in the completion of the mammarenavirus life cycle, suggesting they represent potential druggable targets to counter human pathogenic mammarenavirus infections.

9.
J Infect Dis ; 219(11): 1818-1822, 2019 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-30517671

RESUMO

Lassa fever (LF) survivors develop various clinical manifestations including polyserositis, myalgia, epididymitis, and hearing loss weeks to months after recovery from acute infection. We demonstrate a systemic lymphoplasmacytic and histiocytic arteritis and periarteritis in guinea pigs more than 2 months after recovery from acute Lassa virus (LASV) infection. LASV was detected in the arterial tunica media smooth muscle cells by immunohistochemistry, in situ hybridization, and transmission electron microscopy. Our results suggest that the sequelae of LASV infection may be due to virus persistence resulting in systemic vascular damage. These findings shed light on the pathogenesis of LASV sequelae in convalescent human survivors.

10.
Viruses ; 10(11)2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30463334

RESUMO

Lassa virus (LASV), a mammarenavirus, infects an estimated 100,000⁻300,000 individuals yearly in western Africa and frequently causes lethal disease. Currently, no LASV-specific antivirals or vaccines are commercially available for prevention or treatment of Lassa fever, the disease caused by LASV. The development of medical countermeasure screening platforms is a crucial step to yield licensable products. Using reverse genetics, we generated a recombinant wild-type LASV (rLASV-WT) and a modified version thereof encoding a cleavable green fluorescent protein (GFP) as a reporter for rapid and quantitative detection of infection (rLASV-GFP). Both rLASV-WT and wild-type LASV exhibited similar growth kinetics in cultured cells, whereas growth of rLASV-GFP was slightly impaired. GFP reporter expression by rLASV-GFP remained stable over several serial passages in Vero cells. Using two well-characterized broad-spectrum antivirals known to inhibit LASV infection, favipiravir and ribavirin, we demonstrate that rLASV-GFP is a suitable screening tool for the identification of LASV infection inhibitors. Building on these findings, we established a rLASV-GFP-based high-throughput drug discovery screen and an rLASV-GFP-based antibody neutralization assay. Both platforms, now available as a standard tool at the IRF-Frederick (an international resource), will accelerate anti-LASV medical countermeasure discovery and reduce costs of antiviral screens in maximum containment laboratories.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Genes Reporter , Proteínas de Fluorescência Verde/análise , Vírus Lassa/crescimento & desenvolvimento , Substâncias Luminescentes/análise , Testes de Neutralização/métodos , Coloração e Rotulagem/métodos , Animais , Anticorpos Neutralizantes/imunologia , Antivirais/farmacologia , Fluorometria/métodos , Instabilidade Genômica , Proteínas de Fluorescência Verde/genética , Vírus Lassa/efeitos dos fármacos , Vírus Lassa/genética , Vírus Lassa/imunologia , Genética Reversa , Ribavirina/farmacologia , Células Vero
11.
PLoS Pathog ; 14(7): e1007172, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30028868

RESUMO

The interferon inducible protein, BST-2 (or, tetherin), plays an important role in the innate antiviral defense system by inhibiting the release of many enveloped viruses. Consequently, viruses have evolved strategies to counteract the anti-viral activity of this protein. While the mechanisms by which BST-2 prevents viral dissemination have been defined, less is known about how this protein shapes the early viral distribution and immunological defense against pathogens during the establishment of persistence. Using the lymphocytic choriomeningitis virus (LCMV) model of infection, we sought insights into how the in vitro antiviral activity of this protein compared to the immunological defense mounted in vivo. We observed that BST-2 modestly reduced production of virion particles from cultured cells, which was associated with the ability of BST-2 to interfere with the virus budding process mediated by the LCMV Z protein. Moreover, LCMV does not encode a BST-2 antagonist, and viral propagation was not significantly restricted in cells that constitutively expressed BST-2. In contrast to this very modest effect in cultured cells, BST-2 played a crucial role in controlling LCMV in vivo. In BST-2 deficient mice, a persistent strain of LCMV was no longer confined to the splenic marginal zone at early times post-infection, which resulted in an altered distribution of LCMV-specific T cells, reduced T cell proliferation / function, delayed viral control in the serum, and persistence in the brain. These data demonstrate that BST-2 is important in shaping the anatomical distribution and adaptive immune response against a persistent viral infection in vivo.


Assuntos
Antígenos CD/imunologia , Coriomeningite Linfocítica/imunologia , Linfócitos T/imunologia , Animais , Antígenos CD/metabolismo , Proliferação de Células , Proteínas Ligadas por GPI/imunologia , Proteínas Ligadas por GPI/metabolismo , Humanos , Ativação Linfocitária , Coriomeningite Linfocítica/metabolismo , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL
13.
J Virol ; 92(11)2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29593035

RESUMO

Mammarenaviruses cause chronic infections in their natural rodent hosts. Infected rodents shed infectious virus into excreta. Humans are infected through mucosal exposure to aerosols or direct contact of abraded skin with fomites, resulting in a wide range of manifestations from asymptomatic or mild febrile illness to severe life-threatening hemorrhagic fever. The mammarenavirus matrix Z protein has been shown to be a main driving force of virus budding and to act as a negative regulator of viral RNA synthesis. To gain a better understanding of how the Z protein exerts its several different functions, we investigated the interaction between Z and viral polymerase L protein using the prototypic mammarenavirus, lymphocytic choriomeningitis virus (LCMV). We found that in the presence of an active viral ribonucleoprotein (vRNP), the Z protein translocated from nonionic detergent-resistant, membrane-rich structures to a subcellular compartment with a different membrane composition susceptible to disruption by nonionic detergents. Alanine (A) substitution of a highly conserved leucine (L) at position 72 in LCMV Z protein abrogated Z-L interaction. The L72A mutation did not affect the stability or budding activity of Z when expressed alone, but in the presence of an active vRNP, mutation L72A promoted rapid degradation of Z via a proteasome- and lysosome-independent pathway. Accordingly, L72A mutation in the Z protein resulted in nonviable LCMV. Our findings have uncovered novel aspects of the dynamics of the Z protein for which a highly conserved L residue was strictly required.IMPORTANCE Several mammarenaviruses, chiefly Lassa virus (LASV), cause hemorrhagic fever disease in humans and pose important public health concerns in their regions of endemicity. Moreover, mounting evidence indicates that the worldwide-distributed, prototypic mammarenavirus, lymphocytic choriomeningitis virus (LCMV), is a neglected human pathogen of clinical significance. The mammarenavirus matrix Z protein plays critical roles in different steps of the viral life cycle by interacting with viral and host cellular components. Here we report that alanine substitution of a highly conserved leucine residue, located at position 72 in LCMV Z protein, abrogated Z-L interaction. The L72A mutation did not affect Z budding activity but promoted its rapid degradation in the presence of an active viral ribonucleoprotein (vRNP). Our findings have uncovered novel aspects of the dynamics of the Z protein for which a highly conserved L residue was strictly required.


Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Vírus da Coriomeningite Linfocítica/crescimento & desenvolvimento , RNA Replicase/metabolismo , Ribonucleoproteínas/metabolismo , Proteínas Virais/metabolismo , Liberação de Vírus/genética , Alanina/genética , Substituição de Aminoácidos/genética , Cloreto de Amônio/farmacologia , Animais , Linhagem Celular , Cricetinae , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Leucina/genética , Leupeptinas/farmacologia , Vírus da Coriomeningite Linfocítica/genética , Lisossomos/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , RNA Replicase/genética , Células Vero , Proteínas Virais/genética
14.
PLoS Pathog ; 14(2): e1006892, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29462184

RESUMO

Several mammalian arenaviruses (mammarenaviruses) cause hemorrhagic fevers in humans and pose serious public health concerns in their endemic regions. Additionally, mounting evidence indicates that the worldwide-distributed, prototypic mammarenavirus, lymphocytic choriomeningitis virus (LCMV), is a neglected human pathogen of clinical significance. Concerns about human-pathogenic mammarenaviruses are exacerbated by of the lack of licensed vaccines, and current anti-mammarenavirus therapy is limited to off-label use of ribavirin that is only partially effective. Detailed understanding of virus/host-cell interactions may facilitate the development of novel anti-mammarenavirus strategies by targeting components of the host-cell machinery that are required for efficient virus multiplication. Here we document the generation of a recombinant LCMV encoding a nucleoprotein (NP) containing an affinity tag (rLCMV/Strep-NP) and its use to capture the NP-interactome in infected cells. Our proteomic approach combined with genetics and pharmacological validation assays identified ATPase Na+/K+ transporting subunit alpha 1 (ATP1A1) and prohibitin (PHB) as pro-viral factors. Cell-based assays revealed that ATP1A1 and PHB are involved in different steps of the virus life cycle. Accordingly, we observed a synergistic inhibitory effect on LCMV multiplication with a combination of ATP1A1 and PHB inhibitors. We show that ATP1A1 inhibitors suppress multiplication of Lassa virus and Candid#1, a live-attenuated vaccine strain of Junín virus, suggesting that the requirement of ATP1A1 in virus multiplication is conserved among genetically distantly related mammarenaviruses. Our findings suggest that clinically approved inhibitors of ATP1A1, like digoxin, could be repurposed to treat infections by mammarenaviruses pathogenic for humans.


Assuntos
Coriomeningite Linfocítica/metabolismo , Vírus da Coriomeningite Linfocítica/metabolismo , Nucleoproteínas/metabolismo , Mapas de Interação de Proteínas , Proteoma/análise , Proteínas Repressoras/fisiologia , ATPase Trocadora de Sódio-Potássio/fisiologia , Células A549 , Animais , Arenaviridae/fisiologia , Células Cultivadas , Cricetinae , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/fisiologia , Camundongos , Ligação Proteica , Proteínas Repressoras/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Células Vero
15.
ACS Infect Dis ; 4(5): 815-824, 2018 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-29405696

RESUMO

Several arenaviruses cause hemorrhagic fever (HF) disease in humans and represent important public health problems in their endemic regions. In addition, evidence indicates that the worldwide-distributed prototypic arenavirus lymphocytic choriomeningitis virus is a neglected human pathogen of clinical significance. There are no licensed arenavirus vaccines, and current antiarenavirus therapy is limited to an off-label use of ribavirin that is only partially effective. Therefore, there is an unmet need for novel therapeutics to combat human pathogenic arenaviruses, a task that will be facilitated by the identification of compounds with antiarenaviral activity that could serve as probes to identify arenavirus-host interactions suitable for targeting, as well as lead compounds to develop future antiarenaviral drugs. Screening of a combinatorial library of Krönhke pyridines identified compound KP-146 [(5-(5-(2,3-dihydrobenzo[ b][1,4] dioxin-6-yl)-4'-methoxy-[1,1'-biphenyl]-3-yl)thiophene-2-carboxamide] as having strong anti-lymphocytic choriomeningitis virus (LCMV) activity in cultured cells. KP-146 did not inhibit LCMV cell entry but rather interfered with the activity of the LCMV ribonucleoprotein (vRNP) responsible for directing virus RNA replication and gene transcription, as well as with the budding process mediated by the LCMV matrix Z protein. LCMV variants with increased resistance to KP-146 did not emerge after serial passages in the presence of KP-146. Our findings support the consideration of Kröhnke pyridine scaffold as a valuable source to identify compounds that could serve as tools to dissect arenavirus-host interactions, as well as lead candidate structures to develop antiarenaviral drugs.


Assuntos
Antivirais/farmacologia , Arenavirus/efeitos dos fármacos , Mineração de Dados , Descoberta de Drogas , Piridinas/farmacologia , Bibliotecas de Moléculas Pequenas , Animais , Antivirais/síntese química , Antivirais/química , Infecções por Arenaviridae/tratamento farmacológico , Infecções por Arenaviridae/virologia , Arenavirus/fisiologia , Linhagem Celular , Técnicas de Química Sintética , Relação Dose-Resposta a Droga , Desenho de Drogas , Descoberta de Drogas/métodos , Avaliação Pré-Clínica de Medicamentos , Vírus da Coriomeningite Linfocítica/efeitos dos fármacos , Piridinas/síntese química , Piridinas/química , Células Vero , Replicação Viral/efeitos dos fármacos
16.
Virology ; 511: 106-113, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28843812

RESUMO

Plasmacytoid dendritic cells (pDCs), a main source of type I interferon in response to viral infection, are an early cell target during lymphocytic choriomeningitis virus (LCMV) infection, which has been associated with the LCMV's ability to establish chronic infections. Human blood-derived pDCs have been reported to be refractory to ex vivo LCMV infection. In the present study we show that human pDC CAL-1 cells are refractory to infection with cell-free LCMV, but highly susceptible to infection with recombinant LCMVs carrying the surface glycoprotein of VSV, indicating that LCMV infection of CAL-1 cells is restricted at the cell entry step. Co-culture of uninfected CAL-1 cells with LCMV-infected HEK293 cells enabled LCMV to infect CAL-1 cells. This cell-to-cell spread required direct cell-cell contact and did not involve exosome pathway. Our findings indicate the presence of a novel entry pathway utilized by LCMV to infect pDC.


Assuntos
Células Dendríticas/virologia , Vírus da Coriomeningite Linfocítica/fisiologia , Internalização do Vírus , Células Cultivadas , Técnicas de Cocultura , Humanos
17.
Artigo em Inglês | MEDLINE | ID: mdl-28220142

RESUMO

Junin virus (JUNV), a highly pathogenic New World arenavirus, is the causative agent of Argentine hemorrhagic fever (AHF). The live-attenuated Candid #1 (Can) strain currently serves as a vaccine for at-risk populations. We have previously shown that the Can glycoprotein (GPC) gene is the primary gene responsible for attenuation in a guinea pig model of AHF. However, the mechanisms through which the GPC contributes to the attenuation of the Can strain remain unknown. A more complete understanding of the mechanisms underlying the attenuation and immunogenicity of the Can strain will potentially allow for the rational design of additional safe and novel vaccines. Here, we provide a detailed comparison of both RNA and protein expression profiles between both inter- and intra-segment chimeric JUNV recombinant clones expressing combinations of genes from the Can strain and the pathogenic Romero (Rom) strain. The recombinant viruses that express Can GPC, which were shown to be attenuated in guinea pigs, displayed different RNA levels and GPC processing patterns as determined by Northern and Western blot analyses, respectively. Analysis of recombinant viruses containing amino acid substitutions selected at different mouse brain passages during the generation of Can revealed that altered Can GPC processing was primarily due to the T168A substitution within G1, which eliminates an N-linked glycosylation motif. Incorporation of the T168A substitution in the Rom GPC resulted in a Can-like processing pattern of Rom GPC. In addition, JUNV GPCs containing T168A substitution were retained within the endoplasmic reticulum (ER) and displayed significantly lower cell surface expression than wild-type Rom GPC. Interestingly, the reversion A168T in Can GPC significantly increased GPC expression at the cell surface. Our results demonstrate that recombinant JUNV (rJUNV) expressing Can GPC display markedly different protein expression and elevated genomic RNA expression when compared to viruses expressing Rom GPC. Additionally, our findings indicate that the N-linked glycosylation motif at amino acid positions 166-168 is important for trafficking of JUNV GPC to the cell surface, and the elimination of this motif interferes with the GPC release from the ER.


Assuntos
Motivos de Aminoácidos , Arenavirus do Novo Mundo/imunologia , Glicoproteínas/genética , Glicoproteínas/metabolismo , Febre Hemorrágica Americana , Vacinas Virais , Animais , Arenavirus do Novo Mundo/genética , Linhagem Celular , Células Cultivadas , Cricetinae , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático , Expressão Gênica , Regulação Viral da Expressão Gênica , Glicoproteínas/química , Glicoproteínas/imunologia , Glicosilação , Febre Hemorrágica Americana/imunologia , Febre Hemorrágica Americana/metabolismo , Febre Hemorrágica Americana/prevenção & controle , Febre Hemorrágica Americana/virologia , Humanos , Processamento de Proteína Pós-Traducional , Transporte Proteico , Transcrição Genética , Vacinas Virais/genética , Vacinas Virais/imunologia , Virulência
18.
Immunity ; 45(6): 1270-1284, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-27939671

RESUMO

Infections induce pathogen-specific T cell differentiation into diverse effectors (Teff) that give rise to memory (Tmem) subsets. The cell-fate decisions and lineage relationships that underlie these transitions are poorly understood. Here, we found that the chemokine receptor CX3CR1 identifies three distinct CD8+ Teff and Tmem subsets. Classical central (Tcm) and effector memory (Tem) cells and their corresponding Teff precursors were CX3CR1- and CX3CR1high, respectively. Viral infection also induced a numerically stable CX3CR1int subset that represented ∼15% of blood-borne Tmem cells. CX3CR1int Tmem cells underwent more frequent homeostatic divisions than other Tmem subsets and not only self-renewed, but also contributed to the expanding CX3CR1- Tcm pool. Both Tcm and CX3CR1int cells homed to lymph nodes, but CX3CR1int cells, and not Tem cells, predominantly surveyed peripheral tissues. As CX3CR1int Tmem cells present unique phenotypic, homeostatic, and migratory properties, we designate this subset peripheral memory (tpm) cells and propose that tpm cells are chiefly responsible for the global surveillance of non-lymphoid tissues.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Homeostase/imunologia , Vigilância Imunológica/imunologia , Receptores de Quimiocinas/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Receptor 1 de Quimiocina CX3C , Separação Celular , Citometria de Fluxo , Memória Imunológica/imunologia , Camundongos , Camundongos Endogâmicos C57BL
19.
J Virol ; 90(22): 10102-10112, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27581982

RESUMO

Several arenaviruses, chiefly Lassa virus (LASV), cause hemorrhagic fever disease in humans and pose serious public health concerns in their regions of endemicity. Moreover, mounting evidence indicates that the worldwide-distributed prototypic arenavirus, lymphocytic choriomeningitis virus (LCMV), is a neglected human pathogen of clinical significance. We have documented that a recombinant LCMV containing the glycoprotein (GPC) gene of LASV within the backbone of the immunosuppressive clone 13 (Cl-13) variant of the Armstrong strain of LCMV (rCl-13/LASV-GPC) exhibited Cl-13-like growth properties in cultured cells, but in contrast to Cl-13, rCl-13/LASV-GPC was unable to establish persistence in immunocompetent adult mice, which prevented its use for some in vivo experiments. Recently, V459K and K461G mutations within the GP2 cytoplasmic domain (CD) of rCl-13/LASV-GPC were shown to increase rCl-13/LASV-GPC infectivity in mice. Here, we generated rCl-13(GPC/VGKS) by introducing the corresponding revertant mutations K465V and G467K within GP2 of rCl-13 and we show that rCl-13(GPC/VGKS) was unable to persist in mice. K465V and G467K mutations did not affect GPC processing, virus RNA replication, or gene expression. In addition, rCl-13(GPC/VGKS) grew to high titers in cultured cell lines and in immunodeficient mice. Further analysis revealed that rCl-13(GPC/VGKS) infected fewer splenic plasmacytoid dendritic cells than rCl-13, yet the two viruses induced similar type I interferon responses in mice. Our findings have identified novel viral determinants of Cl-13 persistence and also revealed that virus GPC-host interactions yet to be elucidated critically contribute to Cl-13 persistence. IMPORTANCE: The prototypic arenavirus, lymphocytic choriomeningitis virus (LCMV), provides investigators with a superb experimental model system to investigate virus-host interactions. The Armstrong strain (ARM) of LCMV causes an acute infection, whereas its derivative, clone 13 (Cl-13), causes a persistent infection. Mutations F260L and K1079Q within GP1 and L polymerase, respectively, have been shown to play critical roles in Cl-13's ability to persist in mice. However, there is an overall lack of knowledge about other viral determinants required for Cl-13's persistence. Here, we report that mutations K465V and G467K within the cytoplasmic domain of Cl-13 GP2 resulted in a virus, rCl-13(GPC/VGKS), that failed to persist in mice despite exhibiting Cl-13 wild-type-like fitness in cultured cells and immunocompromised mice. This finding has uncovered novel viral determinants of viral persistence, and a detailed characterization of rCl-13(GPC/VGKS) can provide novel insights into the mechanisms underlying persistent viral infection.


Assuntos
Glicoproteínas/genética , Vírus da Coriomeningite Linfocítica/genética , Vírus da Coriomeningite Linfocítica/patogenicidade , Células A549 , Animais , Linhagem Celular , Linhagem Celular Tumoral , Citoplasma , Células Dendríticas/metabolismo , Células Dendríticas/virologia , Células HEK293 , Interações Hospedeiro-Patógeno/genética , Humanos , Hospedeiro Imunocomprometido/fisiologia , Interferon Tipo I/metabolismo , Vírus Lassa/genética , Vírus Lassa/patogenicidade , Coriomeningite Linfocítica/metabolismo , Coriomeningite Linfocítica/virologia , Camundongos , Mutação/genética , Células Vero , Replicação Viral/genética
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