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1.
PLoS One ; 13(9): e0201341, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30231022

RESUMO

INTRODUCTION: Despite considerable progress, just over half of the 37 million people eligible to start antiretroviral therapy (ART) have accessed treatment and millions of HIV-positive people still do not know their status. With demand for ART continuing to grow, meeting the ambitious 90-90-90 HIV treatment targets will depend on improved access to high-quality diagnostics to both diagnose infection and monitor treatment adherence in low and middle-income countries (LMICs). Robust projections of future demand for CD4, viral load (VL), HIV early-infant-diagnosis (EID) tests and HIV rapid diagnostic tests (RDTs) are needed as scale-up continues. METHODS: We estimate the current coverage for HIV diagnostics and project future demand to 2021 using a consolidated forecast using data on past coverage and current demand from a number of sources, from 130 predominantly LMIC countries. RESULTS: We forecast that the overall number of CD4 tests is expected to decline between now and 2021 as more countries adopt test-and-treat and shift to VL testing for patient monitoring. Our consolidated forecast projects a gradual decline in demand for CD4 tests to 16.6 million by 2021. We anticipate that demand for VL tests will increase to 28.5 million by 2021, reflecting the increasing number of people who will receive ART and the adoption of VL testing for patient monitoring. We expect that the demand for EID tests will grow more rapidly than in past years, driven by the implementation of testing at birth in programmes globally, in line with WHO guideline recommendations, doubling to 2.1 million tests by 2021. Demand for rapid diagnostic tests is also likely to increase, reaching 509 million tests by 2021. DISCUSSION: In order to achieve the ambitious 90-90-90 targets, it will be essential to maintain and improve access to CD4, VL, EID tests and RDTs. These projections provide insight into the global demand we can expect to see for these HIV monitoring and diagnostic tests, both in relation to historical trends, and the 90-90-90 targets. Our projections will better enable producers to ensure adequate supply, and to support procurement organisations in planning future funding and purchase plans to meet the anticipated demand. The findings highlight the ongoing need for governments and international funding bodies to prioritise improving capacity and access to HIV diagnostic and monitoring technologies in line with demand.


Assuntos
Bases de Dados Factuais , Previsões , Infecções por HIV , HIV-1 , Modelos Biológicos , Antirretrovirais/uso terapêutico , Monitoramento Epidemiológico , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Monitorização Fisiológica
2.
J Virol ; 74(17): 7814-23, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10933688

RESUMO

Although prior studies have investigated cellular infection by dengue virus (DV), many have used highly passaged strains. We have reassessed cellular infection by DV type 2 (DV2) using prototype and low-passage isolates representing genotypes from different geographic areas. We observed marked variation in the susceptibility to infection among cell types by different DV2 strains. HepG2 hepatoma cells were susceptible to infection by all DV2 strains assayed. Although the prototype strain generated higher titers of secreted virus than the low-passage isolates, this difference did not correspond to positive- or negative-strand viral RNA levels and thus may reflect variation in efficiency among DV2 isolates to translate viral proteins or package and/or secrete virus. In contrast, human foreskin fibroblasts were susceptible to the prototype and low-passage Thai isolates but not to five Nicaraguan strains tested, as reflected by the absence of accumulation of negative-strand viral RNA, viral antigen, and infectious virus. A similar pattern was observed with the antibody-dependent pathway of infection. U937 and THP-1 myeloid cells and peripheral blood monocytes were infected in the presence of enhancing antibodies by the prototype strain but not by low-passage Nicaraguan isolates. Again, the barrier appeared to be prior to negative-strand accumulation. Thus, depending on the cell type and viral isolate, blocks that limit the production of infectious virus in vitro may occur at distinct steps in the pathway of cellular infection.


Assuntos
Anticorpos Facilitadores/fisiologia , Vírus da Dengue/patogenicidade , Animais , Células Cultivadas , Cricetinae , Vírus da Dengue/isolamento & purificação , Citometria de Fluxo , Humanos , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa
3.
J Virol ; 74(11): 4957-66, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10799569

RESUMO

A role for interferon (IFN) in modulating infection by dengue virus (DV) has been suggested by studies in DV-infected patients and IFN receptor-deficient mice. To address how IFN modulates DV type 2 infection, we have assayed IFN-alpha, -beta, and -gamma for the ability to enhance or diminish antibody-independent and antibody-dependent cell infection using a competitive, asymmetric reverse transcriptase-mediated PCR (RT-PCR) assay that quantitates positive and negative strands of viral RNA, a flow cytometric assay that measures viral antigen, and a plaque assay that analyzes virion production. Our data suggest that IFN-alpha and -beta protect cells against DV infection in vitro. Treatment of hepatoma cells with IFN-alpha or -beta decreases viral RNA levels greater than 1, 000-fold, the percentage of cells infected 90 to 95%, and the amount of infectious virus secreted 150- to 100,000-fold. These results have been reproduced with several cell types and viral strains, including low-passage isolates. In contrast, IFN-gamma has a more variable effect depending on the cell type and pathway of infection. Quantitative RT-PCR experiments indicate that IFN inhibits DV infection by preventing the accumulation of negative-strand viral RNA.


Assuntos
Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Interferon-alfa/farmacologia , Interferon beta/farmacologia , Interferon gama/farmacologia , Animais , Anticorpos Antivirais/imunologia , Linhagem Celular , Cricetinae , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Relação Dose-Resposta a Droga , Humanos , Células K562 , Camundongos , Fatores de Tempo , Células Tumorais Cultivadas , Células U937
4.
J Virol ; 72(12): 10256-9, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9811771

RESUMO

Little is known about the ability of simian virus 40 (SV40) T antigen to bind single-stranded DNA. We demonstrate here that a mutant (259-708) missing the first 258 amino acids of T antigen and its origin-binding domain bound single-stranded DNA at close to normal levels, whereas a mutant containing only the first 259 amino acids failed to bind any single-stranded DNA. The 259-708 mutant also assembled into high-molecular-weight oligomers in the presence of single-stranded DNA. Its ATPase activity was stimulated by single-stranded DNA similarly to the wild type (WT). Furthermore, WT T antigen's ability to bind to single-stranded DNA was inhibited by the binding of two monoclonal antibodies that recognize a region after residue 362. These results show that the domain responsible for binding to single-stranded DNA is completely separate from the origin-binding domain.


Assuntos
Antígenos Transformantes de Poliomavirus/metabolismo , DNA de Cadeia Simples/metabolismo , DNA Viral/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Anticorpos Monoclonais , Anticorpos Antivirais , Antígenos Transformantes de Poliomavirus/química , Antígenos Transformantes de Poliomavirus/genética , Sítios de Ligação/genética , Replicação do DNA , DNA de Cadeia Simples/genética , DNA Viral/genética , Deleção de Sequência
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