RESUMEN
Human T-cell lymphotropic viruses 1 and 2 (HTLV-1/2) are relatively common in Brazil but remain silent and neglected infections. HTLV-1 is associated with a range of diseases with high morbidity and mortality. There is no curative treatment for this lifelong infection, so measures to prevent transmission are essential. This narrative review discusses HTLV-1/2 transmission routes and measures to prevent its continuous dissemination. The public health policies that are currently implemented in Brazil to avoid HTLV-1/2 transmission are addressed, and further strategies are proposed.
Asunto(s)
Infecciones por HTLV-I/transmisión , Infecciones por HTLV-II/transmisión , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Brasil/epidemiología , Infecciones por HTLV-I/epidemiología , Infecciones por HTLV-I/virología , Infecciones por HTLV-II/epidemiología , Infecciones por HTLV-II/virología , Política de Salud , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Política PúblicaRESUMEN
Purification and preparation of three diagnostic antigens used for the detection of human T-lymphotropic virus (HTLV)-I/-II infection in E.coli are different parts of a multi-step method. In this study, our aim was to design a chimeric protein for the simultaneous detection of HTLV-I and HTLV-II antibodies. Immunodominant B cell linear epitopes of envelope and capsid proteins of HTLV-I/-II were selected and linked together; using a suitable amino acid linker and a chimeric antigen (CA). The codon-optimized synthetic DNA encoding the CA was subcloned into the pGS21aexpression vector and CA expressed as His-GST fused protein in E. coli BL21 (DE3) cells. Then the recombinant CA was purified, using the Ni-NTA (Nickle Nitrilotriacetic acid) affinity chromatography under native conditions. The Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and densitometric scanning results showed that CA accounted for 15% of the total cellular proteins and approximately 50% of the expressed histidine-glutathione s-transferase-chimeric antigen (His-GST-CA) proteins were soluble. The CA was successfully purified in one step with a purity of greater than 90%, which is suitable for antigenicity evaluations. Enzyme-linked immunosorbent assay (ELISA) results showed that the GST fused CA reacted in a concentration-dependent manner with HTLV-I/-II infected sera and was able to distinguish normal serum from HTLV-I/-II infected one with a proper sensitivity. With further validation, CA, as described in the present study could be introduced as a novel reliable, cost-effective and easy alternative for the three separate HTLV-I/-II diagnostic peptide antigens, which is prepared as a fusion with GST.
Asunto(s)
Antígenos Virales/metabolismo , Epítopos de Linfocito B/metabolismo , Escherichia coli/inmunología , Infecciones por HTLV-I/diagnóstico , Infecciones por HTLV-II/diagnóstico , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Proteínas Recombinantes de Fusión/metabolismo , Anticuerpos Antivirales/metabolismo , Antígenos Virales/genética , Biología Computacional , Ensayo de Inmunoadsorción Enzimática , Epítopos de Linfocito B/genética , Escherichia coli/virología , Expresión Génica , Humanos , Transportadores de Anión Orgánico/genética , Conformación Proteica , Proteínas Recombinantes de Fusión/genética , Sensibilidad y Especificidad , SerologíaAsunto(s)
Infecciones por HTLV-II/diagnóstico , Virus Linfotrópico T Tipo 2 Humano/aislamiento & purificación , Tamizaje Masivo/métodos , Adulto , Anciano , Femenino , Infecciones por HTLV-I/sangre , Infecciones por HTLV-I/diagnóstico , Infecciones por HTLV-I/virología , Infecciones por HTLV-II/sangre , Infecciones por HTLV-II/virología , Virus Linfotrópico T Tipo 1 Humano/aislamiento & purificación , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Inmunoensayo/métodos , Japón , Mediciones Luminiscentes/métodos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Provision of infection security in transplantology and transfusiology is a challenging and significant problem that depends on the quality of medical donor selection and laboratory diagnosis of the blood collected. At present, a large number of blood-borne viruses are known; nevertheless, in Russia, the list of viral agents to be tested during the examination by the blood service boils down to three ones: HIV, hepatitis C and hepatitis B viruses. The review article demonstrates the need for implementation of additional laboratory tests for the agents of the priority healthcare-associated blood-borne infections (HAI) using a risk-based approach, i.e., on specified sites and in high risk groups. It presents a methodology for determination of a quantitative blood-induced infection residual risk (BIRR) index to be used while evaluating the efficiency of viral security provision in the blood service.
Asunto(s)
Infecciones por Deltaretrovirus/prevención & control , Transmisión de Enfermedad Infecciosa/prevención & control , Infecciones por VIH/prevención & control , Hepatitis Viral Humana/prevención & control , Herpes Simple/prevención & control , Transfusión Sanguínea , Infecciones por Deltaretrovirus/diagnóstico , Infecciones por Deltaretrovirus/epidemiología , Infecciones por Deltaretrovirus/virología , Transmisión de Enfermedad Infecciosa/estadística & datos numéricos , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Infecciones por VIH/virología , VIH-1/patogenicidad , VIH-1/fisiología , VIH-2/patogenicidad , VIH-2/fisiología , Hepacivirus/patogenicidad , Hepacivirus/fisiología , Virus de la Hepatitis B/patogenicidad , Virus de la Hepatitis B/fisiología , Hepatitis Viral Humana/diagnóstico , Hepatitis Viral Humana/epidemiología , Hepatitis Viral Humana/virología , Herpes Simple/diagnóstico , Herpes Simple/epidemiología , Herpes Simple/virología , Virus Linfotrópico T Tipo 1 Humano/patogenicidad , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/patogenicidad , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Federación de Rusia/epidemiología , Simplexvirus/patogenicidad , Simplexvirus/fisiología , Trasplante de TejidosRESUMEN
The human T-cell leukaemia virus type 1 and type 2 (HTLV-1/HTLV-2) antisense proteins HBZ and APH-2 play key roles in the HTLV lifecycles and persistence in the host. Nuclear Factors Associated with double-stranded RNA (NFAR) proteins NF90/110 function in the lifecycles of several viruses and participate in host innate immunity against infection and oncogenesis. Using GST pulldown and co-immunoprecipitation assays we demonstrate specific novel interactions between HBZ/APH-2 and NF90/110 and characterised the protein domains involved. Moreover we show that NF90/110 significantly enhance Tax mediated LTR activation, an effect that was abolished by HBZ but enhanced by APH-2. Additionally we found that HBZ and APH-2 modulate the promoter activity of survivin and are capable of antagonising NF110-mediated survivin activation. Thus interactions between HTLV antisense proteins and the NFAR protein family have an overall positive impact on HTLV infection. Hence NFARs may represent potential therapeutic targets in HTLV infected cells.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Infecciones por HTLV-I/metabolismo , Infecciones por HTLV-I/virología , Interacciones Huésped-Patógeno , Virus Linfotrópico T Tipo 1 Humano/fisiología , Glicoproteínas de Membrana/metabolismo , Proteínas del Factor Nuclear 90/metabolismo , Proteínas de los Retroviridae/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Línea Celular , Espacio Extracelular/metabolismo , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Infecciones por HTLV-I/genética , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Proteínas del Factor Nuclear 90/química , Proteínas del Factor Nuclear 90/genética , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Mapeo de Interacción de Proteínas , Transporte de Proteínas , Interferencia de ARN , Proteínas de los Retroviridae/genética , Survivin , Secuencias Repetidas Terminales , Activación Transcripcional , Técnicas del Sistema de Dos Híbridos , Replicación ViralRESUMEN
Human T-cell leukemia virus type 1 (HTLV-1) is a causative retrovirus of adult T-cell leukemia and HTLV-1-associated myelopathy. Unlike HTLV-1, the same group of retrovirus HTLV-2 has not been found to be associated with these diseases. HTLV-1 and HTLV-2 encode transforming proteins Tax1 and Tax2, and a few distinct activities of Tax1 from those of Tax2 have been proposed to contribute to the HTLV-1-specific pathogenesis of disease. One significant difference of Tax1 from Tax2 is the activation of transcription factor NF-κB2/p100/p52. We found that Tax1 but not Tax2 induces the expression of OX40 ligand (OX40L) in a human T-cell line. To induce the OX40L expression, Tax1 but not Tax2 was observed to interact with NF-κB2/p100/p52 and RelB and the distinct interaction activity was mediated by the Tax1 amino acid region of 225-232. In addition, Tax1 but not Tax2 or Tax1/225-232 interacted with p65, p50, and c-Rel; however, the interactions were much less than those noted with NF-κB2/p100/p52 and RelB. OX40L is a T-cell costimulatory molecule of the tumor necrosis factor family, and its signal plays a critical role in establishing adaptive immunity by inducing the polarized differentiation of T-cells to cells such as T helper type 2 and T follicular helper cells. Therefore, the present findings suggest that Tax1 might alter the immune response to HTLV-1 and/or differentiation of HTLV-1-infected T-cells via OX40L induction, thereby acting as a factor mediating the distinct phenotypes and pathogenesis of HTLV-1 from that of HTLV-2.
Asunto(s)
Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Subunidad p52 de NF-kappa B/metabolismo , Ligando OX40/biosíntesis , Células HEK293 , Virus Linfotrópico T Tipo 1 Humano/inmunología , Virus Linfotrópico T Tipo 2 Humano/inmunología , Humanos , Células Jurkat , Linfocitos T/inmunología , Linfocitos T/virologíaRESUMEN
The retroviral Tax proteins of human T cell leukemia virus type 1 and 2 (HTLV-1 and -2) are highly homologous viral transactivators. Both viral proteins can immortalize human primary CD4+ memory T cells, but when expressed alone they rarely transform T cells. In the present study, we found that the Tax proteins displayed a differential ability to immortalize human CD4+Foxp3+ T cells with characteristic expression of CTLA-4 and GITR. Because epidermal growth factor receptor (EGFR) was reportedly expressed and activated in a subset of CD4+Foxp3+ T cells, we introduced an activated EGFR into Tax-immortalized CD4+Foxp3+ T cells. We observed that these modified cells were grown independently of exogenous IL-2, correlating with a T cell transformation phenotype. In Tax-immortalized CD4+Foxp3- T cells, ectopic expression of Foxp3 was a prerequisite for Tax transformation of T cells. Accordingly, treatment of the transformed T cells with erlotinib, a selective inhibitor of EGFR, induced degradation of EGFR in lysosome, consequently causing T cell growth inhibition. Further, we identified autophagy as a crucial cellular survival pathway for the transformed T cells. Silencing key autophagy molecules including Beclin1, Atg5 and PI3 kinase class III (PI3KC3) resulted in drastic impairment of T cell growth. Our data, therefore, unveiled a previously unidentified role of Foxp3 in T cell transformation, providing a molecular basis for HTLV-1 transformation of CD4+Foxp3+ T cells.
Asunto(s)
Linfocitos T CD4-Positivos/fisiología , Linfocitos T CD4-Positivos/virología , Transformación Celular Viral/fisiología , Factores de Transcripción Forkhead/fisiología , Productos del Gen tax/fisiología , Autofagia/fisiología , Linfocitos T CD4-Positivos/inmunología , Transformación Celular Neoplásica , Transformación Celular Viral/inmunología , Células Cultivadas , Receptores ErbB/fisiología , Virus Linfotrópico T Tipo 1 Humano/patogenicidad , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/patogenicidad , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/fisiología , Subgrupos de Linfocitos T/virologíaRESUMEN
BACKGROUND: The role of innate immunity in general and of type I interferon (IFN-I) in particular in HTLV-1 pathogenesis is still a matter of debate. ADAR1-p150 is an Interferon Stimulated Gene (ISG) induced by IFN-I that can edit viral RNAs. We therefore investigated whether it could play the role of an anti-HTLV factor. RESULTS: We demonstrate here that ADAR1 is also expressed in the absence of IFN stimulation in activated primary T-lymphocytes that are the natural target of this virus and in HTLV-1 or HTLV-2 chronically infected T-cells. ADAR1 expression is also increased in primary lymphocytes obtained from HTLV-1 infected individuals. We show that ADAR1 enhances HTLV-1 and HTLV-2 infection in T-lymphocytes and that this proviral effect is independent from its editing activity. ADAR1 expression suppresses IFN-α inhibitory effect on HTLV-1 and HTLV-2 and acts through the repression of PKR phosphorylation. DISCUSSION: This study demonstrates that two interferon stimulated genes, i.e. PKR and ADAR1 have opposite effects on HTLV replication in vivo. The balanced expression of those proteins could determine the fate of the viral cycle in the course of infection.
Asunto(s)
Adenosina Desaminasa/metabolismo , Interacciones Huésped-Patógeno , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Proteínas de Unión al ARN/metabolismo , Replicación Viral , eIF-2 Quinasa/antagonistas & inhibidores , Células Cultivadas , Humanos , Inhibición Psicológica , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Linfocitos T/inmunología , Linfocitos T/virologíaRESUMEN
Human T-lymphotropic virus (HTLV) infection is a high risk factor for lymphoproliferative, inflammatory, and infectious disorders. The epidemiology of HTLV-I, II in industrialized countries has been intensively investigated, and mandatory screening of blood supplies for HTLV-I/II was implemented in mid-1980s in most developed and several developing countries, yet no expanding investigation has been executed in China so far and also been considered as a non-endemic region. However, Gessain et al. reported that the current number of HTLV carriers in the highly populated China is very probably much higher. Therefore, gaining insight into the epidemiology of HTLV infections is essential for avoiding HTLV-induced risk. To introduce the history and renew the HTLV infection in China, we reviewed literatures and conducted an investigation among blood donors in 9 provinces in China. Concluded from the historical and renewed data, the HTLV screen in China can be divided into three stages.
Asunto(s)
Infecciones por HTLV-I/epidemiología , Infecciones por HTLV-I/historia , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , China/epidemiología , Infecciones por HTLV-I/virología , Historia del Siglo XX , Historia del Siglo XXI , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , HumanosRESUMEN
Human T cell Lymphotropic Viruses 1 and 2 (HTLV-1 and HTLV-2) are the first described human retroviruses. HTLV-1 is the causative agent of an aggressive malignancy of CD4+ T lymphocytes named adult T-cell leukemia/lymphoma (ATLL) and of a chronic neurological disease known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-2 shares many similarities with HTLV-1, but displays lower or absent association to diseases. Among the proteins encoded by HTLVs, the viral transactivator Tax exerts an essential role in viral transcription as well as in cell transformation. Different experimental methods to study Tax activity on HTLV-LTR promoter and Tax subcellular distribution are described. Emphasis is given to the functional and physical interaction between Tax-1/Tax-2 and cellular cofactors which may have an impact on the infectivity process of the HTLVs and on the capacity of cell transformation.
Asunto(s)
Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/metabolismo , Virus Linfotrópico T Tipo 2 Humano/metabolismo , Inmunofenotipificación/métodos , Línea Celular , Productos del Gen tax/genética , Genes Reporteros/genética , Homeostasis , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Immunoblotting , Inmunoprecipitación , Espacio Intracelular/metabolismo , Luciferasas de Luciérnaga/genética , Luciferasas de Renilla/genética , Microscopía Fluorescente , Transporte de Proteínas , Transcripción GenéticaRESUMEN
TaqMan real-time PCR assays were developed to determine the proviral load (PVL) of human T-cell leukemia viruses type 1 and 2 (HTLV-1 and HTLV-2) in peripheral blood mononuclear cells (PBMCs) of infected subjects. In particular, separate single-plex assays for HTLV-1 tax-1, and HTLV-2 tax-2 and pol-2 genes were designed for quantitation of HTLV-1 and HTLV-2 PVLs. The specificity of both tax-2 and pol-2 assays was verified by testing the DNA extracted from C10, a chronically HTLV-1-infected cell line, used as a negative control. As far as HTLV-2 assay, the specificity was checked by testing C344 cells which are stably infected by HTLV-2. Quantitative determination of HTLV PVLs was obtained by performing standard reference curves by a serial dilution of DNA extracted from C10 and C344 cells, assuming one proviral genome per C10 cell and two per C344 cell. The human albumin gene, of which there are 2 copies per cell, was quantified in the same reactions to normalize the results. Intra-assay reproducibility was checked by running 30 replicates of the same sample in a plate (coefficient of variance <6 %), while inter-assay reproducibility was measured by amplifying the same sample in three independent experiments (coefficient of variance <6 %).
Asunto(s)
Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Leucocitos Mononucleares/virología , Provirus/fisiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Carga Viral , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Provirus/genéticaRESUMEN
Retroviral RNA encapsidation involves a recognition event between genomic RNA (gRNA) and one or more domains in Gag. In HIV-1, the nucleocapsid (NC) domain is involved in gRNA packaging and displays robust nucleic acid (NA) binding and chaperone functions. In comparison, NC of human T-cell leukemia virus type 1 (HTLV-1), a deltaretrovirus, displays weaker NA binding and chaperone activity. Mutation of conserved charged residues in the deltaretrovirus bovine leukemia virus (BLV) matrix (MA) and NC domains affects virus replication and gRNA packaging efficiency. Based on these observations, we hypothesized that the MA domain may generally contribute to NA binding and genome encapsidation in deltaretroviruses. Here, we examined the interaction between HTLV-2 and HIV-1 MA proteins and various NAs in vitro. HTLV-2 MA displays higher NA binding affinity and better chaperone activity than HIV-1 MA. HTLV-2 MA also binds NAs with higher affinity than HTLV-2 NC and displays more robust chaperone function. Mutation of two basic residues in HTLV-2 MA α-helix II, previously implicated in BLV gRNA packaging, reduces NA binding affinity. HTLV-2 MA binds with high affinity and specificity to RNA derived from the putative packaging signal of HTLV-2 relative to nonspecific NA. Furthermore, an HIV-1 MA triple mutant designed to mimic the basic character of HTLV-2 MA α-helix II dramatically improves binding affinity and chaperone activity of HIV-1 MA in vitro and restores RNA packaging to a ΔNC HIV-1 variant in cell-based assays. Taken together, these results are consistent with a role for deltaretrovirus MA proteins in viral RNA packaging.
Asunto(s)
Antígenos VIH/metabolismo , Infecciones por VIH/virología , VIH-1/fisiología , Infecciones por HTLV-II/virología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Proteínas de la Nucleocápside/metabolismo , ARN Viral/metabolismo , Ensamble de Virus , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Bovinos , Antígenos VIH/química , Antígenos VIH/genética , VIH-1/química , VIH-1/genética , Virus Linfotrópico T Tipo 2 Humano/química , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Proteínas de la Nucleocápside/química , Proteínas de la Nucleocápside/genética , Unión Proteica , Estructura Secundaria de Proteína , ARN Viral/genética , Alineación de Secuencia , Especificidad de la Especie , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/química , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Type I interferon (IFN-I) inhibits the replication of different viruses. However, the effect of IFN-I on the human T-lymphotropic virus type 1 (HTLV-1) viral cycle is controversial. Here, we investigated the consequences of IFN-α addition for different steps of HTLV-1 and HTLV-2 infection. We first show that alpha interferon (IFN-α) efficiently impairs HTLV-1 and HTLV-2 de novo infection in a T cell line and in primary lymphocytes. Using pseudotyped viruses expressing HTLV-1 envelope, we then show that cell-free infection is insensitive to IFN-α, demonstrating that the cytokine does not affect the early stages of the viral cycle. In contrast, intracellular levels of Gag, Env, or Tax protein are affected by IFN-α treatment in T cells, primary lymphocytes, or 293T cells transfected with HTLV-1 or HTLV-2 molecular clones, demonstrating that IFN-α acts during the late stages of infection. We show that IFN-α does not affect Tax-mediated transcription and acts at a posttranscriptional level. Using either small interfering RNA (siRNA) directed against PKR or a PKR inhibitor, we demonstrate that PKR, whose expression is induced by interferon, plays a major role in IFN-α-induced HTLV-1/2 inhibition. These results indicate that IFN-α has a strong repressive effect on the HTLV-1 and HTLV-2 viral cycle during de novo infection of cells that are natural targets of the viruses.
Asunto(s)
Infecciones por HTLV-I/enzimología , Infecciones por HTLV-II/enzimología , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Interferón-alfa/metabolismo , eIF-2 Quinasa/metabolismo , Línea Celular , Activación Enzimática , Infecciones por HTLV-I/genética , Infecciones por HTLV-I/virología , Infecciones por HTLV-II/genética , Infecciones por HTLV-II/virología , Interacciones Huésped-Patógeno , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Interferón alfa-2 , Proteínas Recombinantes/metabolismo , eIF-2 Quinasa/genéticaRESUMEN
BACKGROUND: Retroviruses HTLV-1 and HTLV-2 have homologous genomic structures but differ significantly in pathogenicity. HTLV-1 is associated with Adult T cell Leukemia (ATL), whereas infection by HTLV-2 has no association with neoplasia. Transformation of T lymphocytes by HTLV-1 is linked to the capacity of its oncoprotein Tax-1 to alter cell survival and cell cycle control mechanisms. Among these functions, Tax-1-mediated activation of cellular gene expression via the NF-κB pathway depends on Tax-1 post-translational modifications by ubiquitination and sumoylation. The Tax-2 protein of HTLV-2B (Tax-2B) is also modified by ubiquitination and sumoylation and activates the NF-κB pathway to a level similar to that of Tax-1. The present study aims to understand whether ubiquitination and sumoylation modifications are involved in Tax-2B-mediated activation of the NF-κB pathway. RESULTS: The comparison of Tax-1 and Tax-2B lysine to arginine substitution mutants revealed conserved patterns and levels of ubiquitination with notable difference in the lysine usage for sumoylation. Neither Tax-1 nor Tax-2B ubiquitination and sumoylation deficient mutants could activate the NF-κB pathway and fusion of ubiquitin or SUMO-1 to the C-terminus of the ubiquitination and sumoylation deficient Tax-2B mutant strikingly restored transcriptional activity. In addition, ubiquitinated forms of Tax-2B colocalized with RelA and IKKγ in prominent cytoplasmic structures associated with the Golgi apparatus, whereas colocalization of Tax-2B with the RelA subunit of NF-κB and the transcriptional coactivator p300 in punctate nuclear structures was dependent on Tax-2B sumoylation, as previously observed for Tax-1. CONCLUSIONS: Both Tax-1 and Tax-2 activate the NF-κB pathway via similar mechanisms involving ubiquitination and sumoylation. Therefore, the different transforming potential of HTLV-1 and HTLV-2 is unlikely to be related to different modes of activation of the canonical NF-κB pathway.
Asunto(s)
Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , FN-kappa B/metabolismo , Sumoilación , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Núcleo Celular/metabolismo , Secuencia Conservada , Proteína p300 Asociada a E1A/metabolismo , Células HEK293 , Células HeLa , Interacciones Huésped-Patógeno , Humanos , Quinasa I-kappa B/metabolismo , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Transporte de Proteínas , Activación Transcripcional , UbiquitinaciónRESUMEN
BACKGROUND: No association between the Human T-cell lymphotropic virus (HTLV), an oncogenic virus that alters host immunity, and the Human Papillomavirus (HPV) has previously been reported. Examining the association between these two viruses may permit the identification of a population at increased risk for developing cervical cancer. METHODS AND FINDINGS: Between July 2010 and February 2011, we conducted a cross-sectional study among indigenous Amazonian Peruvian women from the Shipibo-Konibo ethnic group, a group with endemic HTLV infection. We recruited women between 15 and 39 years of age who were living in the cities of Lima and Ucayali. Our objectives were to determine the association between HTLV and: (i) HPV infection of any type, and (ii) high-risk HPV type infection. Sexually active Shipibo-Konibo women were screened for HTLV-1 and HTLV-2 infections. All HTLV-1 or -2 positive women, along with two community-matched HTLV negative sexually active Shipibo-Konibo controls were later tested for the presence of HPV DNA, conventional cytology, and HIV. We screened 1,253 Shipibo-Konibo women, observing a prevalence of 5.9% (n = 74) for HTLV-1 and 3.8% (n = 47) for HTLV-2 infections. We enrolled 62 (60.8%) HTLV-1 positive women, 40 (39.2%) HTLV-2 positive women, and 205 community-matched HTLV negative controls. HTLV-1 infection was strongly associated with HPV infection of any type (43.6% vs. 29.3%; Prevalence Ratio (PR): 2.10, 95% CI: 1.53-2.87), and with high-risk HPV infection (32.3% vs. 22.4%; PR: 1.93, 95% CI: 1.04-3.59). HTLV-2 was not significantly associated with either of these HPV infections. CONCLUSIONS: HTLV-1 infection was associated with HPV infection of any type and with high-risk HPV infection. Future longitudinal studies are needed to evaluate the incidence of high-risk HPV infection as well as the incidence of cervical neoplasia among HTLV-1 positive women.
Asunto(s)
Infecciones por HTLV-I/complicaciones , Infecciones por HTLV-II/complicaciones , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Papillomaviridae/fisiología , Infecciones por Papillomavirus/complicaciones , Grupos de Población/estadística & datos numéricos , Adolescente , Adulto , Etnicidad/estadística & datos numéricos , Femenino , Infecciones por HTLV-I/epidemiología , Infecciones por HTLV-I/patología , Infecciones por HTLV-I/virología , Infecciones por HTLV-II/epidemiología , Infecciones por HTLV-II/patología , Infecciones por HTLV-II/virología , Humanos , Infecciones por Papillomavirus/epidemiología , Infecciones por Papillomavirus/patología , Infecciones por Papillomavirus/virología , Perú/epidemiología , Prevalencia , Conducta Sexual/estadística & datos numéricos , Adulto JovenRESUMEN
Human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2 are closely related but pathogenically distinct human retroviruses. The antisense strand of the HTLV-1 genome encodes HTLV-1 basic leucine zipper (b-ZIP) protein (HBZ), a protein that inhibits Tax-mediated viral transcription, enhances T-cell proliferation, and promotes viral persistence. Recently, an HTLV-2 antisense viral protein (APH-2) was identified. Despite its lack of a typical b-ZIP domain, APH-2, like HBZ, interacts with cyclic AMP response element binding protein (CREB) and downregulates Tax-mediated viral transcription. Here, we provide evidence that the APH-2 C-terminal LXXLL motif is important for CREB binding and Tax repression. In order to investigate the functional role of APH-2 in the HTLV-2-mediated immortalization of primary T lymphocytes in vitro and in HTLV-2 infection in vivo, we generated APH-2 mutant viruses. In cell cultures, the immortalization capacities of APH-2 mutant viruses were indistinguishable from that of wild-type HTLV-2 (wtHTLV-2), indicating that, like HBZ, APH-2 is dispensable for viral infection and cellular transformation. In vivo, rabbits inoculated with either wtHTLV-2 or APH-2 mutant viruses established a persistent infection. However, the APH-2 knockout virus displayed an increased replication rate, as measured by an increased viral antibody response and a higher proviral load. In contrast to HTLV-1 HBZ, we show that APH-2 is dispensable for the establishment of an efficient infection and persistence in a rabbit animal model. Therefore, antisense proteins of HTLV-1 and HTLV-2 have evolved different functions in vivo, and further comparative studies will provide fundamental insights into the distinct pathobiologies of these two viruses.
Asunto(s)
Transformación Celular Viral , Virus Linfotrópico T Tipo 2 Humano/fisiología , Proteínas Virales/metabolismo , Replicación Viral , Animales , Células Cultivadas , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Modelos Animales de Enfermedad , Productos del Gen tax/metabolismo , Infecciones por HTLV-II/virología , Humanos , Unión Proteica , Conejos , Linfocitos T/virologíaRESUMEN
Human T lymphotropic virus type 1 (HTLV-1) and HTLV-2 are related but pathogenically distinct viruses. HTLV-1 mainly causes adult T cell leukemia, while HTLV-2 is not associated with leukemia. In vitro, HTLV-1 and HTLV-2 predominantly transform CD4(+) and CD8(+) T cells, respectively: the genetic determinant maps to the viral envelope. Herein, we investigate whether this transformation tropism occurs during initial infection or subsequently during the cellular transformation process. Since most individuals are chronically infected at the time of detection, we utilized an established rabbit model to longitudinally measure the early HTLV-1 and HTLV-2 infection and replication kinetics in purified CD4(+) and CD8(+) T cells. HTLV-1 and HTLV-2 were detected in both CD4(+) and CD8(+) T cells within 1 week postinoculation. In HTLV-1-infected rabbit CD4(+) T cells, proviral burden and tax/rex mRNA expression peaked early, and expression levels were directly proportional to each other. The late expression of the antisense transcript (Hbz or Aph-2) correlated directly with a late proviral burden peak in HTLV-1- or HTLV-2-infected rabbit CD8(+) T cells, respectively. This study provides the first in vivo evidence that these viruses do not exhibit cellular preference during initial infection. We further evaluated the transformation tropism of HTLV-1 and HTLV-2 over a 9-week period using in vitro cell growth/immortalization assays. At the early weeks, both HTLV-1 and HTLV-2 showed proportionate growth of CD4(+) and CD8(+) T cells. However, beyond week 5, the predominance of one particular T cell type emerged, supporting the conclusion that transformation tropism is a postinfection event due to selective clonal expansion over time.
Asunto(s)
Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/virología , Transformación Celular Viral , Infecciones por HTLV-II/virología , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Tropismo Viral , Animales , Linfocitos T CD4-Positivos/citología , Linfocitos T CD8-positivos/citología , Proliferación Celular , Células Cultivadas , Regulación Viral de la Expresión Génica , Productos del Gen tax/genética , Productos del Gen tax/metabolismo , Infecciones por HTLV-II/fisiopatología , Virus Linfotrópico T Tipo 1 Humano/genética , Virus Linfotrópico T Tipo 2 Humano/genética , Humanos , Masculino , ConejosRESUMEN
BACKGROUND: MHC class II transactivator CIITA inhibits the function of HTLV-2 Tax-2 viral transactivator and, consequently, the replication of the virus in infected cells. Moreover overexpression of the nuclear factor NF-YB, that cooperates with CIITA for the expression of MHC class II genes, results also in inhibition of Tax-2 transactivation. The purpose of this investigation was to assess the cellular and molecular basis of the CIITA-mediated inhibition on Tax-2, and the relative role of NF-YB in this phenomenon. METHODS: By co-immunoprecipitation of lysates from 293T cells cotransfected with CIITA or fragments of it, and Tax-2 it was assessed whether the two factors interact in vivo. A similar approach was used to assess Tax-2-NF-YB interaction. In parallel, deletion fragments of CIITA were tested for the inhibition of Tax-2-dependent HTLV-2 LTR-luciferase transactivation. Subcellular localization of CIITA and Tax-2 was investigated by immunofluorescence and confocal microscopy. RESULTS: CIITA and Tax-2 interact in vivo through at least two independent regions, at the 1-252 N-term and at the 410-1130 C-term, respectively. Interestingly only the 1-252 N-term region mediates Tax-2 functional inhibition. CIITA and Tax-2 are localized both in the cytoplasm and in the nucleus, when separately expressed. Instead, when coexpressed, most of Tax-2 colocalize with CIITA in cytoplasm and around the nuclear membrane. The Tax-2 minor remaining nuclear portion also co-localizes with CIITA. Interestingly, when CIITA nucleus-cytoplasm shuttling is blocked by leptomycin B treatment, most of the Tax-2 molecules are also blocked and co-localize with CIITA in the nucleus, suggesting that CIITA-Tax-2 binding does not preclude Tax-2 entry into the nucleus.Finally, the nuclear factor NF-YB, also strongly binds to Tax-2. Notably, although endogenous NF-YB does not inhibit Tax-2-dependent HTLV-2 LTR transactivation, it still binds to Tax-2, and in presence of CIITA, this binding seems to increase. CONCLUSIONS: These results strongly suggest that CIITA inhibit Tax-2 by binding the viral transactivator both directly or through a tripartite interaction with NF-YB in. CIITA is therefore a viral restriction factor for HTLV-2 and this open the possibility to control HTLV-2 viral replication and spreading by the controlled induction of CIITA in infected cells.
Asunto(s)
Productos del Gen tax/antagonistas & inhibidores , Virus Linfotrópico T Tipo 2 Humano/fisiología , Proteínas Nucleares/metabolismo , Transactivadores/metabolismo , Replicación Viral/fisiología , Factor de Unión a CCAAT/metabolismo , Productos del Gen tax/metabolismo , Células HEK293 , Humanos , Proteínas Nucleares/química , Unión Proteica , Transporte de Proteínas , Fracciones Subcelulares/metabolismo , Transactivadores/químicaRESUMEN
Thiosemicarbazones display a wide antimicrobial activity by targeting bacteria, fungi, and viruses. Here, we report our studies on the antiviral activity of two thiosemicarbazone metal complexes, [bis(citronellalthiosemicarbazonato)nickel(II)] and [aqua(pyridoxalthiosemicarbazonato)copper(II)] chloride monohydrate, against the retroviruses HIV-1 and HTLV-1/-2. Both compounds exhibit antiviral properties against HIV but not against HTLVs . In particular, the copper complex shows the most potent anti-HIV activity by acting at the post-entry steps of the viral cycle.
Asunto(s)
Antirretrovirales/síntesis química , Complejos de Coordinación/síntesis química , VIH-1/efectos de los fármacos , Virus Linfotrópico T Tipo 1 Humano/efectos de los fármacos , Virus Linfotrópico T Tipo 2 Humano/efectos de los fármacos , Tiosemicarbazonas/síntesis química , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Antirretrovirales/química , Antirretrovirales/farmacología , Supervivencia Celular , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , VIH-1/fisiología , Virus Linfotrópico T Tipo 1 Humano/fisiología , Virus Linfotrópico T Tipo 2 Humano/fisiología , Humanos , Técnicas In Vitro , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/virología , Relación Estructura-Actividad , Tiosemicarbazonas/química , Tiosemicarbazonas/farmacología , Internalización del Virus , Replicación Viral/efectos de los fármacosRESUMEN
David D. Derse, Ph.D., Head of the Retrovirus Gene Expression Section in the HIV Drug Resistance Program at the National Cancer Institute-Frederick (NCI-Frederick), passed away on October 9, 2009, a scant six weeks after being diagnosed with liver cancer. It was with great sadness that family, friends, and colleagues gathered together for his memorial service on Saturday, October 17, 2009, at the Middletown United Methodist Church in Maryland. As a NCI scientist since 1986, Dave studied the molecular mechanisms of infection and replication of a number of different types of retroviruses. Dave became an internationally known expert on human T cell lymphotrophic viruses type 1 and 2 (HTLV-1 and HTLV-2) and served on the editorial boards of Virology and Retrovirology. His most recent studies focused on the mechanisms of HTLV-1 virion morphogenesis, transmission, and replication.