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1.
Viruses ; 13(2)2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33530304

RESUMO

Cellular restriction factors (RFs) act as important constitutive innate immune barriers against viruses. In 2006, the promyelocytic leukemia protein was described as the first RF against human cytomegalovirus (HCMV) infection which is antagonized by the viral immediate early protein IE1. Since then, at least 15 additional RFs against HCMV have been identified, including the chromatin regulatory protein SPOC1, the cytidine deaminase APOBEC3A and the dNTP triphosphohydrolase SAMHD1. These RFs affect distinct steps of the viral replication cycle such as viral entry, gene expression, the synthesis of progeny DNA or egress. This review summarizes our current knowledge on intrinsic immune mechanisms restricting HCMV replication as well as on the viral strategies to counteract the inhibitory effects of RFs. Detailed knowledge on the interplay between host RFs and antagonizing viral factors will be fundamental to develop new approaches to combat HCMV infection.


Assuntos
Infecções por Citomegalovirus/virologia , Citomegalovirus/fisiologia , Replicação Viral , Infecções por Citomegalovirus/imunologia , DNA Viral/metabolismo , Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/metabolismo , Imunidade Inata , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Internalização do Vírus
2.
Viruses ; 13(2)2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33567734

RESUMO

Human cytomegalovirus (HCMV) is a ubiquitous double-stranded DNA virus belonging to the ß-subgroup of the herpesvirus family. After the initial infection, the virus establishes latency in poorly differentiated myeloid precursors from where it can reactivate at later times to cause recurrences. In immunocompetent subjects, primary HCMV infection is usually asymptomatic, while in immunocompromised patients, HCMV infection can lead to severe, life-threatening diseases, whose clinical severity parallels the degree of immunosuppression. The existence of a strict interplay between HCMV and the immune system has led many to hypothesize that HCMV could also be involved in autoimmune diseases (ADs). Indeed, signs of active viral infection were later found in a variety of different ADs, such as rheumatological, neurological, enteric disorders, and metabolic diseases. In addition, HCMV infection has been frequently linked to increased production of autoantibodies, which play a driving role in AD progression, as observed in systemic lupus erythematosus (SLE) patients. Documented mechanisms of HCMV-associated autoimmunity include molecular mimicry, inflammation, and nonspecific B-cell activation. In this review, we summarize the available literature on the various ADs arising from or exacerbating upon HCMV infection, focusing on the potential role of HCMV-mediated immune activation at disease onset.


Assuntos
Doenças Autoimunes/imunologia , Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Autoanticorpos/imunologia , Doenças Autoimunes/patologia , Doenças Autoimunes/virologia , Autoimunidade , Citomegalovirus/patogenicidade , Infecções por Citomegalovirus/patologia , Infecções por Citomegalovirus/virologia , Humanos , Hospedeiro Imunocomprometido , Inflamação , Doenças Vasculares/patologia
3.
BMJ Case Rep ; 13(12)2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33372022

RESUMO

We present a previously healthy man in his 30s who presented with typical viral prodrome symptoms and worsening abdominal pain. He was found to have portal vein thrombosis, with extensive hypercoagulability workup performed. It was determined that the aetiology of thrombus was secondary to acute cytomegalovirus infection. The patient was started on anticoagulation therapy, with later clot resolution demonstrated on abdominal Doppler ultrasound and abdominal CT scan. Given the atypical presentation of this common virus, we performed a literature review of cytomegalovirus-associated portal vein thrombosis in healthy individuals; we found that most patients present with non-specific symptoms of fever and abdominal pain in the setting of a viral prodrome. This case and literature review suggest physicians must consider cytomegalovirus-associated portal vein thrombosis as a potential diagnosis when patients present with abdominal pain and viral symptoms. The literature highlights the need for a consensus on anticoagulation and antiviral therapy.


Assuntos
Infecções por Citomegalovirus/complicações , Veia Porta , Trombose Venosa/virologia , Dor Abdominal/etiologia , Adulto , Anticoagulantes/uso terapêutico , Transtornos da Coagulação Sanguínea/tratamento farmacológico , Transtornos da Coagulação Sanguínea/virologia , Angiografia por Tomografia Computadorizada , Infecções por Citomegalovirus/imunologia , Humanos , Imunocompetência , Masculino , Veia Porta/diagnóstico por imagem , Ultrassonografia Doppler , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/tratamento farmacológico
4.
BMJ Case Rep ; 13(12)2020 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-33310821

RESUMO

A previously well and immunocompetent 64-year-old woman presented with fever of unknown origin and acute hepatitis. Besides headache and nausea, she had no other symptoms. Her clinical examination was unremarkable with no clear focus of infection. She was thoroughly investigated and her biochemical profile suggested a viral or autoimmune aetiology. Multiple imaging modalities gave no further insight. Her serology and subsequent nucleic acid amplification indicated reactivation of latent cytomegalovirus (CMV). Her symptoms resolved with supportive care and no anti-viral therapy was needed. This case report highlights CMV reactivation leading to acute hepatitis in a well, immunocompetent patient.


Assuntos
Infecções por Citomegalovirus/complicações , Hepatite Viral Humana/etiologia , Imunocompetência , Doença Aguda , Anticorpos Antivirais/sangue , Citomegalovirus , Infecções por Citomegalovirus/imunologia , Feminino , Hepatite Viral Humana/diagnóstico , Hepatite Viral Humana/imunologia , Humanos , Pessoa de Meia-Idade
5.
PLoS Pathog ; 16(12): e1009169, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370407

RESUMO

Human cytomegalovirus (HCMV) is the primary viral cause of congenital birth defects and causes significant morbidity and mortality in immune-suppressed transplant recipients. Despite considerable efforts in vaccine development, HCMV infection still represents an unmet clinical need. In recent phase II trials, a MF59-adjuvanted gB vaccine showed only modest efficacy in preventing infection. These findings might be attributed to low level of antibodies (Abs) with a neutralizing activity induced by this vaccine. Here, we analyzed the immunogenicity of each gB antigenic domain (AD) and demonstrated that domain I of gB (AD5) is the main target of HCMV neutralizing antibodies. Furthermore, we designed, characterized and evaluated immunogenic responses to two different nanoparticles displaying a trimeric AD5 antigen. We showed that mice immunization with nanoparticles induces sera neutralization titers up to 100-fold higher compared to those obtained with the gB extracellular domain (gBECD). Collectively, these results illustrate with a medically relevant example the advantages of using a general approach combining antigen discovery, protein engineering and scaffold presentation for modern development of subunit vaccines against complex pathogens.


Assuntos
Anticorpos Antivirais/imunologia , Infecções por Citomegalovirus/imunologia , Vacinas contra Citomegalovirus/imunologia , Nanopartículas , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Citomegalovirus/imunologia , Infecções por Citomegalovirus/prevenção & controle , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Vacinas de Subunidades/imunologia
6.
Stroke ; 51(10): 3156-3168, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32897811

RESUMO

Understanding the relationship between infection and stroke has taken on new urgency in the era of the coronavirus disease 2019 (COVID-19) pandemic. This association is not a new concept, as several infections have long been recognized to contribute to stroke risk. The association of infection and stroke is also bidirectional. Although infection can lead to stroke, stroke also induces immune suppression which increases risk of infection. Apart from their short-term effects, emerging evidence suggests that poststroke immune changes may also adversely affect long-term cognitive outcomes in patients with stroke, increasing the risk of poststroke neurodegeneration and dementia. Infections at the time of stroke may also increase immune dysregulation after the stroke, further exacerbating the risk of cognitive decline. This review will cover the role of acute infections, including respiratory infections such as COVID-19, as a trigger for stroke; the role of infectious burden, or the cumulative number of infections throughout life, as a contributor to long-term risk of atherosclerotic disease and stroke; immune dysregulation after stroke and its effect on the risk of stroke-associated infection; and the impact of infection at the time of a stroke on the immune reaction to brain injury and subsequent long-term cognitive and functional outcomes. Finally, we will present a model to conceptualize the many relationships among chronic and acute infections and their short- and long-term neurological consequences. This model will suggest several directions for future research.


Assuntos
Aterosclerose/epidemiologia , Infecções/epidemiologia , Acidente Vascular Cerebral/epidemiologia , Arritmias Cardíacas/epidemiologia , Arritmias Cardíacas/fisiopatologia , Aterosclerose/imunologia , Aterosclerose/fisiopatologia , Bacteriemia/epidemiologia , Bacteriemia/imunologia , Bacteriemia/fisiopatologia , Betacoronavirus , Doença Crônica , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/fisiopatologia , Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/fisiopatologia , Endotélio/fisiopatologia , Infecções por HIV/epidemiologia , Infecções por HIV/imunologia , Infecções por HIV/fisiopatologia , Humanos , Hospedeiro Imunocomprometido/imunologia , Infecções/imunologia , Infecções/fisiopatologia , Inflamação/imunologia , Influenza Humana/epidemiologia , Influenza Humana/imunologia , Influenza Humana/fisiopatologia , Pandemias , Ativação Plaquetária , Agregação Plaquetária , Pneumonia/epidemiologia , Pneumonia/imunologia , Pneumonia/fisiopatologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/imunologia , Pneumonia Viral/fisiopatologia , Prognóstico , Fatores de Risco , Acidente Vascular Cerebral/imunologia , Trombose/epidemiologia , Trombose/imunologia , Infecção pelo Vírus da Varicela-Zoster/epidemiologia , Infecção pelo Vírus da Varicela-Zoster/imunologia , Infecção pelo Vírus da Varicela-Zoster/fisiopatologia
7.
PLoS Pathog ; 16(8): e1008736, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745149

RESUMO

Human cytomegalovirus (HCMV) is one of the main causative agents of congenital viral infection in neonates. HCMV infection also causes serious morbidity and mortality among organ transplant patients. Glycoprotein B (gB) is a major target for HCMV neutralizing antibodies, yet the underlying neutralization mechanisms remain largely unknown. Here we report that 3-25, a gB-specific monoclonal antibody previously isolated from a healthy HCMV-positive donor, efficiently neutralized 14 HCMV strains in both ARPE-19 cells and MRC-5 cells. The core epitope of 3-25 was mapped to a highly conserved linear epitope on antigenic domain 2 (AD-2) of gB. A 1.8 Å crystal structure of 3-25 Fab in complex with the peptide epitope revealed the molecular determinants of 3-25 binding to gB at atomic resolution. Negative-staining electron microscopy (EM) 3D reconstruction of 3-25 Fab in complex with de-glycosylated postfusion gB showed that 3-25 Fab fully occupied the gB trimer at the N-terminus with flexible binding angles. Functionally, 3-25 efficiently inhibited HCMV infection at a post-attachment step by interfering with viral membrane fusion, and restricted post-infection viral spreading in ARPE-19 cells. Interestingly, bivalency was required for HCMV neutralization by AD-2 specific antibody 3-25 but not the AD-4 specific antibody LJP538. In contrast, bivalency was not required for HCMV binding by both antibodies. Taken together, our results reveal the structural basis of gB recognition by 3-25 and demonstrate that inhibition of viral membrane fusion and a requirement of bivalency may be common for gB AD-2 specific neutralizing antibody.


Assuntos
Anticorpos Antivirais/imunologia , Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Epitopos/imunologia , Proteínas do Envelope Viral/imunologia , Motivos de Aminoácidos , Anticorpos Neutralizantes/imunologia , Sequência Conservada , Citomegalovirus/química , Citomegalovirus/genética , Citomegalovirus/fisiologia , Infecções por Citomegalovirus/virologia , Epitopos/química , Epitopos/genética , Humanos , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Internalização do Vírus
8.
Virology ; 548: 182-191, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32838941

RESUMO

Human cytomegalovirus (HCMV) is the most common congenital infection. A glycoprotein B (gB) subunit vaccine (gB/MF59) is the most efficacious clinically tested to date, having achieved 50% protection against primary infection of HCMV-seronegative women. We previously identified that gB/MF59 vaccination primarily elicits non-neutralizing antibody responses, with variable binding to gB genotypes, and protection associated with binding to membrane-associated gB. We hypothesized that gB-specific non-neutralizing antibody binding breadth and function are dependent on epitope and genotype specificity, and ability to interact with membrane-associated gB. We mapped twenty-four gB-specific monoclonal antibodies (mAbs) from naturally HCMV-infected individuals for gB domain specificity, genotype preference, and ability to mediate phagocytosis or NK cell activation. gB-specific mAbs were primarily specific for Domain II and demonstrated variable binding to gB genotypes. Two mAbs facilitated phagocytosis with binding specificities of Domain II and AD2. This investigation provides novel understanding on the relationship between gB domain specificity and antigenic variability on gB-specific antibody effector functions.


Assuntos
Anticorpos Antivirais/imunologia , Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Proteínas do Envelope Viral/imunologia , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Especificidade de Anticorpos , Citomegalovirus/genética , Infecções por Citomegalovirus/sangue , Infecções por Citomegalovirus/virologia , Feminino , Humanos , Masculino , Proteínas do Envelope Viral/genética , Adulto Jovem
9.
Virology ; 548: 93-100, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32838950

RESUMO

Human cytomegalovirus (HCMV) infects the chorioamnion, but whether these infections cause fetal membrane dysfunction remains poorly understood. We sought to assess whether guinea pig cytomegalovirus (GPCMV) infects amnion-derived cells in vitro, compare the inflammatory response of amnion cells to GPCMV and HCMV, and determine if GPCMV infects the amnion in vivo. We found that GPCMV replicates in primary guinea pig amnion derived cells and HPV16 E6/E7-transduced amniotic epithelial cells (AEC[E6/E7]s). HCMV and GPCMV infection of amnion cells increased the transcription of the chemokines CCL5/Ccl5, CXCL8/Cxcl8, and CXCL10/Cxcl10. Myd88-knockdown decreased Ccl5 and Cxc8 transcription in GPCMV-infected AEC[E6/E7]s. GPCMV was detected in the guinea pig amnion after primary maternal infection, revealing that guinea pigs are an appropriate model to study fetal membrane physiology after cytomegalovirus infection. As inflammation is known to cause fetal membrane weakening, the amnion's response to cytomegalovirus infection may cause preterm birth and other adverse pregnancy outcomes.


Assuntos
Âmnio/imunologia , Quimiocinas/imunologia , Infecções por Citomegalovirus/imunologia , Citomegalovirus/fisiologia , Complicações na Gravidez/imunologia , Âmnio/virologia , Animais , Quimiocina CCL5/genética , Quimiocina CCL5/imunologia , Quimiocina CXCL10/genética , Quimiocina CXCL10/imunologia , Quimiocinas/genética , Citomegalovirus/genética , Citomegalovirus/imunologia , Infecções por Citomegalovirus/genética , Feminino , Cobaias , Humanos , Interleucina-8/genética , Interleucina-8/imunologia , Gravidez , Complicações na Gravidez/genética , Complicações na Gravidez/virologia
11.
Rev Med Virol ; 30(5): e2144, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32671966

RESUMO

The significantly higher mortality rates seen in the elderly compared with young children during the coronavirus disease 2019 (Covid-19) pandemic is likely to be driven in part by an impaired immune response in older individuals. Cytomegalovirus (CMV) seroprevalence approaches 80% in the elderly. CMV has been shown to accelerate immune ageing by affecting peripheral blood T cell phenotypes and increasing inflammatory mediated cytokines such as IL-6. The elderly with pre-existing but clinically silent CMV infection may therefore be particularly susceptible to severe Covid-19 disease and succumb to a cytokine storm which may have been promoted by CMV. Here, we evaluate the potential role of CMV in those with severe Covid-19 disease and consider how this relationship can be investigated in current research studies.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Síndrome da Liberação de Citocina/epidemiologia , Infecções por Citomegalovirus/epidemiologia , Citomegalovirus/patogenicidade , Imunossenescência , Pandemias , Pneumonia Viral/epidemiologia , Fatores Etários , Idoso , Betacoronavirus/imunologia , Criança , Coinfecção , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/virologia , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/mortalidade , Síndrome da Liberação de Citocina/virologia , Citocinas/genética , Citocinas/imunologia , Citomegalovirus/imunologia , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/mortalidade , Infecções por Citomegalovirus/virologia , Progressão da Doença , Humanos , Pneumonia Viral/imunologia , Pneumonia Viral/mortalidade , Pneumonia Viral/virologia , Estudos Soroepidemiológicos , Índice de Gravidade de Doença , Análise de Sobrevida , Linfócitos T/imunologia , Linfócitos T/patologia , Linfócitos T/virologia
12.
PLoS Pathog ; 16(7): e1008560, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667948

RESUMO

Human cytomegalovirus (HCMV) causes serious complications to immune compromised hosts. Dendritic cells (iDCgB) expressing granulocyte-macrophage colony-stimulating factor, interferon-alpha and HCMV-gB were developed to promote de novo antiviral adaptive responses. Mice reconstituted with a human immune system (HIS) were immunized with iDCgB and challenged with HCMV, resulting into 93% protection. Immunization stimulated the expansion of functional effector memory CD8+ and CD4+ T cells recognizing gB. Machine learning analyses confirmed bone marrow T/CD4+, liver B/IgA+ and spleen B/IgG+ cells as predictive biomarkers of immunization (≈87% accuracy). CD8+ and CD4+ T cell responses against gB were validated. Splenic gB-binding IgM-/IgG+ B cells were sorted and analyzed at a single cell level. iDCgB immunizations elicited human-like IgG responses with a broad usage of various IgG heavy chain V gene segments harboring variable levels of somatic hypermutation. From this search, two gB-binding human monoclonal IgGs were generated that neutralized HCMV infection in vitro. Passive immunization with these antibodies provided proof-of-concept evidence of protection against HCMV infection. This HIS/HCMV in vivo model system supported the validation of novel active and passive immune therapies for future clinical translation.


Assuntos
Anticorpos Antivirais/imunologia , Infecções por Citomegalovirus/imunologia , Vacinas contra Citomegalovirus/imunologia , Imunização Passiva , Imunoglobulina G/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Antígenos Virais/imunologia , Citomegalovirus/imunologia , Células Dendríticas/imunologia , Modelos Animais de Doenças , Humanos , Imunoglobulina G/farmacologia , Camundongos
13.
Acta Virol ; 64(2): 117-130, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32551781

RESUMO

Viruses have evolved sophisticated strategies to subvert immunity to benefit overall viral fitness. Human cytomegalovirus (HCMV, ß-herpesvirus) represents a paradigm of very effective hijacking of gene functions that imitate host encoded immunomodulatory proteins. This co-evolution with the host immune system allowed for establishment of lifelong persistence. The HCMV infection is largely asymptomatic in healthy persons; however, it can induce serious disease in immunocompromised individuals. For this reason, great attention is paid to the development of therapeutics based on HCMV immunomodulatory 'tricks' as well as to the search for active vaccine against HCMV. While comparing the HCMV clinical isolates with extensively passaged laboratory strains, the unique long (UL) b' locus was commonly found to be deleted in HCMV genome while adapted to replication in human fibroblasts in vitro. This missing region, called UL/b' region, encodes up to 22 canonical genes with different functions, as of targeting cellular tropism (e.g. UL133-UL138); viral entry and assembly (e.g. UL128, UL130, UL131A); regulation of immunological synapses (e.g. UL135); inhibition of NK and T cell function (e.g. UL141, UL142, UL148, UL144), ablating activity (e.g. UL146, UL147), but mainly aimed at manipulating the host immune response. Moreover, the presence of UL/b' genomic region dramatically correlates with adverse effects in vaccinated persons, indicating that viral genes in this region play a significant role in controlling virulence. Here, we review how HCMV shapes our immunity by hijacked genes originated from UL/b' locus, discuss their impact in immunomodulation mechanism and how this knowledge may translate to clinical applications. Keywords: immunomodulation; HCMV genes; UL/b' locus; NK cell function; HCMV vaccine; immunity; immunotherapeutics.


Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus , Genes Virais , Deleção de Sequência , Citomegalovirus/genética , Citomegalovirus/imunologia , Humanos , Glicoproteínas de Membrana/genética , Proteínas Virais/genética , Tropismo Viral/genética , Internalização do Vírus
14.
Transplant Proc ; 52(6): 1852-1854, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32571698

RESUMO

OBJECTIVES: Valganciclovir (VGCV) is used as prophylaxis against cytomegalovirus (CMV) infection after pediatric living donor liver transplantation (LDLT). The purpose of this study was to examine the efficacy of 1 year of preemptive VGCV administration compared with a shorter administration after pediatric LDLT. METHODS: VGCV was administered to 56 children who underwent LDLT. CMV and Epstein-Barr virus (EBV) antibody status, pp65 antigenemia, and other laboratory data were assessed at 1 year after LDLT. Patients were divided into the 1-year group (n = 32) (patients who had 1 year of VGCV administration) and the <1-year group (n = 24) (patients who had less than 1 year of VGCV administration). RESULTS: Study participants consisted of 34 females and 22 males, with a mean age of 4.2 years at transplant. Regarding pretransplant donor (D)/recipient (R) CMV antibody status, 13 were D positive (+)/R negative (-), 27 were D+/R+, 8 were D-/R+, and 8 were D-/R-. For EBV, 22 were D+/R+, 32 were D+/R-, and 2 were D-/R-. In the 1-year group, only 2 patients (6.5%) developed CMV infection, whereas 8 patients (33.3%) developed CMV infection in the <1-year group. The CMV pp65 antigenemia assay was positive in 2 patients. CMV IgM was positive in 7 patients. One year of preemptive VGCV administration was associated with a lower incidence of CMV infection (P = .008), but not EBV infection. No adverse effects were observed. CONCLUSIONS: One year of preemptive VGCV administration after LDLT is safe and suppresses CMV infection. It was useful after pediatric LDLT.


Assuntos
Antivirais/administração & dosagem , Infecções por Citomegalovirus/prevenção & controle , Transplante de Fígado , Valganciclovir/administração & dosagem , Adolescente , Antivirais/efeitos adversos , Criança , Pré-Escolar , Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/imunologia , Feminino , Ganciclovir/uso terapêutico , Humanos , Hospedeiro Imunocomprometido , Incidência , Transplante de Fígado/efeitos adversos , Doadores Vivos , Masculino , Fatores de Tempo , Valganciclovir/efeitos adversos
15.
Hematol Oncol ; 38(4): 554-559, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32583904

RESUMO

Ruxolitinib is effective in myeloproliferative neoplasms (MPN) but can cause reactivation of silent infections. We aimed at evaluating viral load and T-cell responses to human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in a cohort of 25 MPN patients treated with ruxolitinib. EBV-DNA and HCMV-DNA were quantified monthly using real-time polimerase chain reaction (PCR) on peripheral blood samples, and T-cell subsets were analyzed by flowcytometry. HCMV and EBV-directed T-cell responses were evaluated using the IFN-γ ELISPOT assay. Most patients had CD4+ and/or CD8+ T-cells below the normal range; these reductions were related to the duration of ruxolitinib treatment. In fact, reduced T-lymphocytes' subsets were found in 93% of patients treated for ≥5 years and in 45% of those treated for <5 years (P = .021). The former also had lower median numbers of CD4+ and CD8+ cells. Subclinical reactivation of EBV and HCMV occurred in 76% and 8% of patients. We observed a trend to an inverse relationship between EBV and CMV-specific CD4+ and CD8+ T-cell responses and viral load, and a trend to an inverse correlation with ruxolitinib dose. Therefore, our data suggest that the ruxolitinib treatment may interfere with immunosurveillance against EBV and HCMV.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por Citomegalovirus/imunologia , Infecções por Vírus Epstein-Barr/imunologia , Transtornos Mieloproliferativos/imunologia , Pirazóis/farmacologia , Ativação Viral/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/virologia , Citomegalovirus/efeitos dos fármacos , Citomegalovirus/imunologia , Infecções por Citomegalovirus/tratamento farmacológico , Infecções por Citomegalovirus/virologia , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Infecções por Vírus Epstein-Barr/virologia , Feminino , Seguimentos , Herpesvirus Humano 4/efeitos dos fármacos , Herpesvirus Humano 4/imunologia , Humanos , Interferon gama/metabolismo , Masculino , Pessoa de Meia-Idade , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/virologia , Prognóstico , Taxa de Sobrevida , Carga Viral , Ativação Viral/efeitos dos fármacos
16.
PLoS Pathog ; 16(5): e1008537, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32365141

RESUMO

Promyelocytic leukemia (PML) bodies are nuclear organelles implicated in intrinsic and innate antiviral defense. The eponymous PML proteins, central to the self-organization of PML bodies, and other restriction factors found in these organelles are common targets of viral antagonism. The 72-kDa immediate-early protein 1 (IE1) is the principal antagonist of PML bodies encoded by the human cytomegalovirus (hCMV). IE1 is believed to disrupt PML bodies by inhibiting PML SUMOylation, while PML was proposed to act as an E3 ligase for IE1 SUMOylation. PML targeting by IE1 is considered to be crucial for hCMV replication at low multiplicities of infection, in part via counteracting antiviral gene induction linked to the cellular interferon (IFN) response. However, current concepts of IE1-PML interaction are largely derived from mutant IE1 proteins known or predicted to be metabolically unstable and globally misfolded. We performed systematic clustered charge-to-alanine scanning mutagenesis and identified a stable IE1 mutant protein (IE1cc172-176) with wild-type characteristics except for neither interacting with PML proteins nor inhibiting PML SUMOylation. Consequently, IE1cc172-176 does not associate with PML bodies and is selectively impaired for disrupting these organelles. Surprisingly, functional analysis of IE1cc172-176 revealed that the protein is hypermodified by mixed SUMO chains and that IE1 SUMOylation depends on nucleosome rather than PML binding. Furthermore, a mutant hCMV expressing IE1cc172-176 was only slightly attenuated compared to an IE1-null virus even at low multiplicities of infection. Finally, hCMV-induced expression of cytokine and IFN-stimulated genes turned out to be reduced rather than increased in the presence of IE1cc172-176 relative to wild-type IE1. Our findings challenge present views on the relationship of IE1 with PML and the role of PML in hCMV replication. This study also provides initial evidence for the idea that disruption of PML bodies upon viral infection is linked to activation rather than inhibition of innate immunity.


Assuntos
Infecções por Citomegalovirus , Citomegalovirus/fisiologia , Proteínas Imediatamente Precoces , Imunidade Inata , Proteína da Leucemia Promielocítica , Replicação Viral , Linhagem Celular , Infecções por Citomegalovirus/genética , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/patologia , Regulação Viral da Expressão Gênica/imunologia , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/imunologia , Mutação , Proteína da Leucemia Promielocítica/genética , Proteína da Leucemia Promielocítica/imunologia , Sumoilação/imunologia , Replicação Viral/genética , Replicação Viral/imunologia
17.
Med Sci (Paris) ; 36(4): 367-375, 2020 Apr.
Artigo em Francês | MEDLINE | ID: mdl-32356713

RESUMO

Human cytomegalovirus (HCMV) is an important ubiquitous opportunistic pathogen that belongs to the betaherpesviridae. Primary HCMV infection is generally asymptomatic in immunocompetent individuals. In contrast, HCMV infection causes serious disease in immunocompromised patients and is the leading cause of congenital viral infection. Although they are effective, the use of conventional molecules is limited by the emergence of resistance and by their toxicity. New antivirals targeting other replication steps and inducing fewer adverse effects are therefore needed. During HCMV replication, DNA packaging is performed by the terminase complex, which cleaves DNA to package the virus genome into the capsid. With no counterpart in mammalian cells, these terminase proteins are ideal targets for highly specific antivirals. A new terminase inhibitor, letermovir, recently proved effective against HCMV in phase III clinical trials. However, its mechanism of action is unclear and it has no significant activity against other herpesvirus or non-human CMV.


Assuntos
Antivirais/uso terapêutico , Infecções por Citomegalovirus/tratamento farmacológico , Endodesoxirribonucleases/antagonistas & inibidores , Terapia de Alvo Molecular/métodos , Citomegalovirus/patogenicidade , Citomegalovirus/fisiologia , Infecções por Citomegalovirus/imunologia , Endodesoxirribonucleases/fisiologia , Humanos , Hospedeiro Imunocomprometido , Terapia de Alvo Molecular/tendências , Complexos Multiproteicos/antagonistas & inibidores , Complexos Multiproteicos/fisiologia , Montagem de Vírus/efeitos dos fármacos , Montagem de Vírus/fisiologia , Replicação Viral/efeitos dos fármacos
18.
Proc Natl Acad Sci U S A ; 117(23): 12961-12968, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32444487

RESUMO

Viral immune evasion is currently understood to focus on deflecting CD8 T cell recognition of infected cells by disrupting antigen presentation pathways. We evaluated viral interference with the ultimate step in cytotoxic T cell function, the death of infected cells. The viral inhibitor of caspase-8 activation (vICA) conserved in human cytomegalovirus (HCMV) and murine CMV (MCMV) prevents the activation of caspase-8 and proapoptotic signaling. We demonstrate the key role of vICA from either virus, in deflecting antigen-specific CD8 T cell-killing of infected cells. vICA-deficient mutants, lacking either UL36 or M36, exhibit greater susceptibility to CD8 T cell control than mutants lacking the set of immunoevasins known to disrupt antigen presentation via MHC class I. This difference is evident during infection in the natural mouse host infected with MCMV, in settings where virus-specific CD8 T cells are adoptively transferred. Finally, we identify the molecular mechanism through which vICA acts, demonstrating the central contribution of caspase-8 signaling at a point of convergence of death receptor-induced apoptosis and perforin/granzyme-dependent cytotoxicity.


Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Interações entre Hospedeiro e Microrganismos/imunologia , Evasão da Resposta Imune , Linfócitos T Citotóxicos/imunologia , Animais , Apoptose/imunologia , Caspase 8/genética , Caspase 8/metabolismo , Linhagem Celular , Técnicas de Cocultura , Citomegalovirus/patogenicidade , Infecções por Citomegalovirus/virologia , Modelos Animais de Doenças , Fibroblastos , Granzimas/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Camundongos , Camundongos Knockout , Muromegalovirus/genética , Muromegalovirus/imunologia , Muromegalovirus/metabolismo , Mutagênese , Perforina/genética , Perforina/metabolismo , Receptores de Morte Celular/metabolismo , Transdução de Sinais/imunologia , Linfócitos T Citotóxicos/metabolismo , Imagem com Lapso de Tempo , Proteínas Virais/genética , Proteínas Virais/imunologia , Proteínas Virais/metabolismo
19.
Sci Rep ; 10(1): 7194, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32346028

RESUMO

The QuantiFERON-CMV (QF) assay measures cell-mediated immunity against cytomegalovirus (CMV-CMI), which is particularly useful in individuals susceptible to CMV infection such as transplant patients. A positive QF result identifies patients that are better protected against CMV infection. However, the significance of a negative QF result in CMV-seropositive individuals needs to be clarified. CMV-CMI was analyzed in healthy subjects using the QF assay, and, in parallel, the Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood (FASCIA). FASCIA assay measures T-cell proliferation using CMV lysate as stimulus whereas QF assay use a mix of peptides. A total of 93 healthy volunteers were enrolled, and 13/71 CMV-seropositive individuals (18.3%) showed humoral/cellular discordance using QF assay (CMV+ QF-). Interestingly, with FASCIA assay CD4+ and CD8+ T-cell proliferations were lower in CMV+ QF- than in CMV+ QF+ individuals. Furthermore, CMV+ QF- volunteers had a lower level of anti-CMV IgG than CMV+ QF+ subjects. Discordant CMV+ QF- volunteers can be defined as low responder individuals since they show lower CMV-specific humoral and cellular immune responses in comparison to CMV+ QF+ individuals. Immune discordance shows the high heterogeneity of immunity to CMV in healthy subjects.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Imunidade Celular , Adulto , Anticorpos Antivirais/imunologia , Feminino , Humanos , Imunoensaio , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade
20.
Cancer Immunol Immunother ; 69(8): 1535-1548, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32300857

RESUMO

With an infection rate of 60-90%, the human cytomegalovirus (HCMV) is very common among adults but normally causes no symptoms. When T cell-mediated immunity is compromised, HCMV reactivation can lead to increased morbidity and mortality. HCMV antigens are processed and presented as peptides on the cell surface via HLA I complexes to the T cell receptor (TCR) of T cells. The generation of antibodies against HCMV peptides presented on HLA complexes (TCR-like antibodies) has been described, but is without therapeutic applications to date due to the polygenic and polymorphic nature of HLA genes. We set out to obtain antibodies specific for HLA/HCMV-peptides, covering the majority of HLA alleles present in European populations. Using phage display technology, we selected 10 Fabs, able to bind to HCMV-peptides presented in the 6 different HLA class I alleles A*0101, A*0201, A*2402, B*0702, B*0801 and B*3501. We demonstrate specific binding of all selected Fabs to HLA-typed lymphoblastoid cell lines (EBV-transformed B cells) and lymphocytes loaded with HCMV-peptides. After infection with HCMV, 4/10 tetramerized Fabs restricted to the alleles HLA-A*0101, HLA-A*0201 and HLA-B*0702 showed binding to infected primary fibroblasts. When linked to the pseudomonas exotoxin A, these Fab antibodies induce highly specific cytotoxicity in HLA matched cell lines loaded with HCMV peptides. TCR-like antibody repertoires therefore represent a promising new treatment modality for viral infections and may also have applications in the treatment of cancers.


Assuntos
Infecções por Citomegalovirus/prevenção & controle , Citomegalovirus/imunologia , Fibroblastos/imunologia , Antígenos HLA/imunologia , Fragmentos Fab das Imunoglobulinas/administração & dosagem , Fragmentos de Peptídeos/imunologia , Linfócitos T Citotóxicos/imunologia , Antígenos Virais/imunologia , Sobrevivência Celular , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/metabolismo , Infecções por Citomegalovirus/virologia , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fab das Imunoglobulinas/metabolismo , Imunotoxinas/administração & dosagem , Melanoma/imunologia , Melanoma/metabolismo , Melanoma/patologia , Melanoma/prevenção & controle , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas Virais/imunologia
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