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A Ureta-Vidal

Publications and source records attributed to A Ureta-Vidal.

10 recordsLinked to original sources
PubMed2003

Ensembl 2002: accommodating comparative genomics.

The Ensembl (http://www.ensembl.org/) database project provides a bioinformatics framework to organise biology around the sequences of large genomes. It is a comprehensive source of stable automatic annotation of human, mouse and other genome sequences, available as either an interactive web site or as flat files. Ensembl also integrates manually annotated gene structures from external sources where available. As well as being one of the leading sources of genome annotation, Ensembl is an open source software engineering project to develop a portable system able to handle very large genomes and associated requirements. These range from sequence analysis to data storage and visualisation and installations exist around the world in both companies and at academic sites. With both human and mouse genome sequences available and more vertebrate sequences to follow, many of the recent developments in Ensembl have focusing on developing automatic comparative genome analysis and visualisation.

Animals↗
PubMed2002

The Ensembl genome database project.

The Ensembl (http://www.ensembl.org/) database project provides a bioinformatics framework to organise biology around the sequences of large genomes. It is a comprehensive source of stable automatic annotation of the human genome sequence, with confirmed gene predictions that have been integrated with external data sources, and is available as either an interactive web site or as flat files. It is also an open source software engineering project to develop a portable system able to handle very large genomes and associated requirements from sequence analysis to data storage and visualisation. The Ensembl site is one of the leading sources of human genome sequence annotation and provided much of the analysis for publication by the international human genome project of the draft genome. The Ensembl system is being installed around the world in both companies and academic sites on machines ranging from supercomputers to laptops.

Computational Biology↗
PubMed2001

Human T cell leukemia virus Type I (HTLV-I) infection induces greater expansions of CD8 T lymphocytes in persons with HTLV-I-associated myelopathy/tropical spastic paraparesis than in asymptomatic carriers.

A quantitative study of the T cell receptor repertoire was performed ex vivo on CD4 and CD8 T cell subsets of human T cell leukemia virus type I (HTLV-I)-infected asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Indexes of oligoclonality that compiled all repertoire modifications were calculated for peripheral blood mononuclear cells and for CD4 and CD8 T cell subsets. Both patients with HAM/TSP and asymptomatic carriers had greater T lymphocyte expansions than did uninfected donors, which was independent of age and at least twice higher in the CD8 than in the CD4 cell compartment. Some expanded CD8 T cells corresponded to cytotoxic T lymphocytes directed against various epitopes of the immunodominant Tax protein. Patients with HAM/TSP had significantly higher CD8 cell expansions than did asymptomatic carriers. These results highlight the prognostic value of measuring CD8 T cell expansions during follow-up of HTLV-I infection.

Adult↗
PubMed2001

Design of a polyepitope construct for the induction of HLA-A0201-restricted HIV 1-specific CTL responses using HLA-A*0201 transgenic, H-2 class I KO mice.

HLA-A*0201 transgenic, H-2D(b)/mouse beta2-microglobulin double-knockout mice were used to compare and optimize the immunogenic potential of 17HIV 1-derived,HLA-A0201-restricted epitopic peptides. A tyrosine substitution in position 1 of the epitopic peptides, which increases both their affinity for and their HLA-A0201 molecule stabilizing capacity, was introduced in a significant proportion, having verified that such modifications enhance their immunogenicity in respect of their natural antigenicity. Based on these results, a 13-polyepitope construct was inserted in the pre-S2 segment of the hepatitis B middle glycoprotein and used for DNA immunization. Long-lasting CTL responses against most of the inserted epitopes could be elicited simultaneously in a single animal with cross-recognition in several cases of their most common natural variants.

AIDS Vaccines↗
PubMed2000

Evidence for the chronic in vivo production of human T cell leukemia virus type I Rof and Tof proteins from cytotoxic T lymphocytes directed against viral peptides.

Human T cell leukemia virus type I (HTLV-I) is a persistent virus that causes adult T cell leukemia and tropical spastic paraparesis/HTLV-I-associated myelopathy. Studies on rabbits have shown that viral proteins encoded by the open reading frames pX-I and pX-II are required for the establishment of the persistent infection. To examine the in vivo production of these proteins in humans, we have investigated whether cytotoxic T lymphocytes isolated from HTLV-I-infected individuals recognized pX-I and pX-II peptides. CD8(+) T lymphocytes to pX-I and pX-II peptides were detected in HTLV-I-infected individuals, whatever their clinical status, and even in the absence of any antigenic restimulation. These findings indicate that the HTLV-I pX-I and pX-II proteins are chronically synthesized in vivo, and are targets of the natural immune response to the virus.

Amino Acid Sequence↗
PubMed2000

Lymphoid organs as a major reservoir for human T-cell leukemia virus type 1 in experimentally infected squirrel monkeys (Saimiri sciureus): provirus expression, persistence, and humoral and cellular immune responses.

The aim of this study was to investigate the distribution of human T-cell leukemia virus type 1 (HTLV-1) in various organs of serially sacrificed squirrel monkeys (Saimiri sciureus) in order to localize the reservoir of the virus and to evaluate the relationship between viral expression and the humoral or cellular immune response during infection. Six squirrel monkeys infected with HTLV-1 were sacrificed 6, 12, and 35 days and 3, 6, and 26 months after inoculation, and 20 organs and tissues were collected from each animal. PCR and reverse transcription-PCR (RT-PCR) were performed with gag and tax primers. Proviral DNA was detected by PCR in peripheral blood mononuclear cells (PBMCs) of monkeys sacrificed 6 days after inoculation and in PBMCs, spleens, and lymph nodes of monkeys sacrificed 12 and 35 days and 3, 6, and 26 months after inoculation. Furthermore, tax/rex mRNA was detected by RT-PCR in the PBMCs of two monkeys 8 to 12 days after inoculation and in the spleens and lymph nodes of the monkey sacrificed on day 12. In this animal, scattered HTLV-1 tax/rex mRNA-positive lymphocytes were detected by in situ hybridization in frozen sections of the spleen, around the germinal centers and close to the arterial capillaries. Anti-HTLV-1 cell-mediated immunity was evaluated at various times after inoculation. Anti-p40(Tax) and anti-Env cytolytic T-cell responses were detected 2 months after infection and remained detectable thereafter. When Tax peptides were used, this response appeared to be directed against various Tax epitopes. Our results indicate that squirrel monkeys represent a promising animal model for studying the early events of HTLV-1 infection and for evaluating candidate vaccines against HTLV-1.

Animals↗
PubMed1999

Mother-to-child transmission of human T-cell-leukemia/lymphoma virus type I: implication of high antiviral antibody titer and high proviral load in carrier mothers.

In order to gain new insights into the risk factors influencing human-T-cell-leukemia/lymphoma-virus-type-I (HTLV-I) mother-to-child transmission, a retrospective study of HTLV-I infection among children born to HTLV-I-seropositive women was carried out in a highly HTLV-I-endemic population of African origin living in French Guyana. The study covered 81 HTLV-I-seropositive mothers and their 216 children aged between 18 months old and 12 years old. All plasma samples were tested for the presence of HTLV-I antibodies by ELISA, immunofluorescence assay and Western blot. HTLV-I provirus was detected, in the DNA extracted from peripheral-blood mononuclear cells, by polymerase chain reaction (PCR) using primers specific for 3 different HTLV-I genomic regions (LTR, gag and pX) and quantified by a competitive PCR assay. Out of the 216 children, 21 were found to be HTLV-I-seropositive, giving a crude HTLV-I transmission rate of 9.7%, while among the 180 breast-fed children 10.6% were HTLV-I-seropositive. Perfect concordance between serological and PCR results was observed, and none of the 195 HTLV-I-negative children was found HTLV-I-positive by PCR. In conditional (by family) logistic-regression models, HTLV-I seropositivity in children was associated with an elevated maternal anti-HTLV-I-antibody titer (OR 2.2, p = 0.0013), a high maternal HTLV-I proviral load (OR 2.6, p = 0.033) and child's gender, girls being more frequently HTLV-I-infected than boys: OR 3.6, p = 0.0077 in the model including maternal anti-HTLV-I-antibody titer and OR 4.1, p = 0.002 in the model including the maternal HTLV-I proviral load.

Breast Feeding↗
PubMed1999

Phenotypical and functional characterization of the CD8+ T cell repertoire of HLA-A2.1 transgenic, H-2KbnullDbnull double knockout mice.

Homozygous HLA-A2.1 transgenic H-2KbnullDbnull double knockout (KO) mice were created. Their potential to develop HLA-A2. 1-restricted cytolytic responses was compared with that of their classical transgenic counterparts, which still express H-2Kb, Db molecules. On cell surfaces, both strains express similar amounts of chimeric (alpha 1 alpha 2 domains of human, alpha 3 cytoplasmic domains of mouse) HLA-A2.1 molecules in noncovalent association with mouse beta 2-microglobulin. Compared with mice that are totally deprived of histocompatibility class Ia molecules (H-2KbnullDbnull double KO), the expression of HLA-A2.1 in transgenic/double KO mice resulted in sizeable increase in the periphery of CD8+ T cells with a normally diversified TCR repertoire. A biased education in favor of HLA-A2.1, ascribable to the absence of H-2 class Ia molecules, was evidenced in these transgenic/double KO mice by their improved capacity to mount HLA-restricted cytolytic responses, regardless of whether they were virally infected or injected with synthetic epitopic peptide. HLA class I transgenic, H-2 class Ia KO mice should represent useful animal models for the preclinical evaluation of vaccine formulations aiming at the induction of HLA class I-restricted CTL responses.

Animals↗
PubMed1995

Risk factors for maternal HTLV-I infection in French Guiana: high HTLV-I prevalence in the Noir Marron population.

The aim of this study was to compare rates of human T-cell lymphotropic virus type I (HTLV-I) seroprevalence in pregnant women belonging to different ethnic groups in French Guiana and to determine the risk factors associated with HTLV-I seropositivity. All 1,873 deliveries between 1 July 1991 and 30 June 1993 in the only gynecologic and obstetric unit at Saint Laurent du Maroni were enrolled. Serologic status could be established for 1,727 women, with 75 (4.3%) being HTLV-I seropositive. The HTLV-I seroprevalence rate differed significantly between ethnic groups: 5.7% for Noir-Marron (70/1,302), 6.3% for Haitian (3/50), and 0% for Creole (126), Amerindians (166), and Hmong (64). In Noir-Marron pregnant women, HTLV-I seropositivity was associated with a maternal age of > 35 years [odds ratio (OR), 3.3; 95% confidence interval (CI), 1.4-7.6], prior miscarriage (OR, 1.7; CI, 1-2.8), prior cesarean section (OR, 2.1; CI, 1.1-4.0), a parity > 4 (OR, 4.0; CI, 1.8-8.8), a gravidity > 6 (OR, 4.2; CI, 2.0-7.2), and a negative Rhesus factor (OR, 2.2; CI, 1.1-4.5). Two separate stepwise logistic regressions were done because gravidity and parity were highly correlated. HTLV-I seropositivity remained associated with a gravidity > 6 (OR, 3.9; CI, 2.1-7.4) and a negative Rhesus factor (OR, 2.6; CI, 1.2-5.3) for the first model and with a parity > 4 (OR, 4.1; CI, 1.9-9.0) and a negative Rhesus factor (OR, 2.5; CI, 1.2-5.1) for the second model.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗