摘要:

Objective:Clinical experience with HIV-1 protease inhibitors (PIs) in the treatment of AIDS frequently has shown that increases in CD4+T-cell counts can be independent of HIV-1 inhibition by these drugs. This disconnection between viral load and CD4 counts led us to investigate how the PI ritonavir directly affects leukocyte activation in vitro, using peripheral blood mononuclear cell (PBMC) fractions derived from normal donors.Methods and Results:When uninfected PBMC cultures were treated for 72 hours with ritonavir at concentrations similar to or lower than that shown to be effective in vivo, an increase in cell viability was observed. The susceptibility of PBMCs to apoptosis was markedly decreased after ritonavir treatment and correlated with lower levels of caspase-1 expression, decreases in annexin V staining, and reduced caspase-3 activity. Induction in vitro of tumor necrosis factor (TNF) production by PBMCs and monocytes was inhibited by ritonavir in a time- and dose-dependent manner at nontoxic concentrations.Conclusion:Based on our data, we conclude that the HIV-1 PI ritonavir is an immune modulator that may affect leukocyte activation and apoptosis as an important part of its therapeutic benefit.Journal of Human Virology 1999;2:261-269 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Select C-C and C-X-C chemokines can suppress HIV infection. This is because their receptors are the gateways for HIV-1 entry, determinants of viral tropism and sensitivity. C-C chemokines are most effective against macrophage-tropic viruses, and C-X-C chemokines are most effective against T-tropic viruses. The epitopes on the chemokine molecule responsible for virus inhibition and for chemokines' specificities are not known. The objective of this study was to map the functional domains of prototypic antiviral chemokine, namely, RANTES (regulated-on-activation normal T-expressed and secreted).Study Design:Optimal folding of the chemokine molecule is thought to be important for its biologic activity. Anticipating that it will provide a native milieu for folding, we expressed recombinant RANTES molecules in an HIV-2-derived lentivirus mammalian expression system. We focused on the structural landmarks of RANTES to determine their role in its life and function.Results:We found that the flexible amino-terminal region of RANTES was not important for its structural integrity or antiviral activity, either positively or negatively. It was also not important for binding to the CCR5 receptor. Modification of all other domains was detrimental, implying a functional role. However, a more careful analysis revealed that these domains were crucial for controlling stability, transport, and secretion of the molecule. Although all recombinant clones contained signal sequence and were transcriptionally active, they presented three different phenotypes: normal synthesis and secretion, normal synthesis but blocked secretion, and presumed normal synthesis but rapid degradation. Structural considerations and preliminary experiments showing a lack of effect of proteasome inhibitors suggested that the signal recognition particle pathway of translocation and proteasomal pathway of destruction may not be the major determinant of the life of the chemokine.Conclusions:The amino-terminal domain of RANTES was not essential for its antiviral activity or for its binding to the CCR5 receptor. Although the 1-domain of the core and carboxyterminal domain may contribute to the antiviral activity of RANTES, they were more important for its intracellular life.Journal of Human Virology 1999;2:270-282 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:This study was undertaken to determine the contribution of HIV co-receptors and &bgr; chemokine secretion to the increased susceptibility for human immunodeficiency virus (HIV) infection of peripheral blood mononuclear cells (PBMC) obtained from HIV-seronegative Ethiopian immigrants in Israel (ETH).Study Design:Immune activation markers and HIV co-receptor expression on lymphocytes and monocytes, and &bgr; chemokine secretion by CD8+cells, were compared between ETH and non-Ethiopian Israeli (IS) HIV-negative individuals.Results:The percentage of lymphocytes and monocytes expressing CCR5 was 1.6 and 3.0 times higher in ETH (n= 83) than in IS (n= 45), respectively (P< .001), whereas RANTES and MIP-1&agr; secretion was 0.5 and 0.7 times lower (P< .01 andP< .05). The percentage of CCR5-expressing cells and RANTES secretion were inversely correlated (r = -0.7;P< .002). No differences were found in the proportion of CXCR4-expressing cells. No correlation between CCR5 expression and cell activation profile in the whole ETH population was found. However, in highly activated individuals (HLA-DR/CD3 >7%), a significant decrease in CCR5 expression was observed.Conclusions:An increased proportion of CCR5-expressing cells with decreased &bgr; chemokine secretion observed in ETH may account for the increased susceptibility to HIV infection of cells obtained from this group. These findings may partly explain the higher susceptibility for HIV infection in Africa and thus the rapid spread of acquired immunodeficiency syndrome (AIDS) in that continent.Journal of Human Virology 1999;2:283-289 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:This study was undertaken to examine 6-bp insertions following codon 69 in the reverse transcriptase (RT) coding region of human immunodeficiency virus type 1 (HIV-1) mutations in terms of incidence, presence of additional RT mutations, phenotypic drug resistance, HIV-1 RNA levels, and antiretroviral treatment history.Study Design/Methods:A retrospective study of 121 nucleoside reverse transcriptase inhibitor (NRTI)-experienced subjects infected with HIV-1 was performed. Methods included quantitation of HIV-1 RNA levels, genotypic analyses of the RT and protease coding regions, and determination of phenotypic drug resistance.Results:A 6-bp insertion following RT codon 69 was observed in viral isolates from 4 subjects. Two subjects had a history of zidovudine (ZDV)-based therapy, and two subjects had a history of stavudine (D4T)-based therapy without prior exposure to ZDV. The T69S mutation and the 6-bp insertion following RT codon 69 were the only RT mutations observed in the 2 subjects with a history of D4T-based therapy.Conclusions:Six-basepair insertions occurred in virus from 4 of 121 (3%) NRTI-experienced subjects, including those without prior ZDV treatment, and was observed in the absence of the T215Y mutation. There was no apparent correlation between insertion incidence and HIV-1 viremia.Journal of Human Virology 1999;2:290-295 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To identify cellular factors in human liver that interact with hepatitis C virus (HCV) 5′ and 3′ untranslated regions (UTRs) and therefore possibly are involved in the regulation of HCV transcription or translation.Methods:We prepared cytoplasmic extracts from human liver biopsy samples and fractionated cellular factors on ion exchange columns. The various fractions from ion exchange columns were subjected to ultraviolet (UV) cross-linking with radiolabeled HCV 5′ and 3′ UTR RNA probes.Results:Two major 45- and 46-kd proteins that interacted specifically with the HCV 5′ and 3′ UTR were identified. Using Western blot and immunoprecipitation, these proteins were identified as the La antigen.ConclusionOur results demonstrate that the La protein from human liver biopsy cells interacts specifically with the U-rich region in the positive strand of the HCV 3′ UTR.Journal of Human Virology 1999;2:296-307 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine whether a unique human T-lymphotropic virus type I (HTLV-I) transmission cohort containing multiple disease manifestations could be used to establish a relationship betweentaxgene sequence and HTLV disease expression.Methods:DNA was extracted from the peripheral blood mononuclear cells (PBMC) of the HTLV-infected persons in the cohort. A 1.1-kb fragment oftaxwas amplified by polymerase chain reaction (PCR) and cloned. Six to 12 individual clones were sequenced per person.Results:Comparison to a reference ATK strain showed numerous differences; however, consensustaxsequences from all persons within the transmission cohort were identical. Intraperson variation was 0.1% to 0.3%.Taxsequences from the index case did not differ from those obtained from a transfusion recipient who developed tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM).Taxsequences from the same index case did not differ from sequences obtained from the asymptomatic or ATL phases of a second recipient.Conclusions:In this cohort there did not appear to betaxgenotypes associated with specific disease manifestations of HTLV infection.Journal of Human Virology 1999;2:308-314 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Kaposi's sarcoma (KS) is an acquired immunodeficiency syndrome (AIDS)-defining neoplasm histologically characterized by proliferation of spindle cells, inflammatory cells, and abundant neovascularization. When the malignant cell line KSY-1 derived from an AIDS-KS tumor is transplanted subcutaneously into nude mice, prominent neovascular features develop. Using this mouse model of neoplastic KS, we set out to determine, usingc-ets 1markers specific for mouse or human tissues, whether vascular growth and inflammatory infiltrate induced by the transplanted KSY-1 cells is of host cell or transplant origin.Study Design/Methods:KS tumors were induced by subcutaneous inoculation of 5 × 106KSY-1 cells/200 &mgr;L in immunodeficient mice, and species-specific mouse and human riboprobes of thec-ets 1protooncogene were used for in situ hybridization to define cell of origin.Results:Five different tumors were examined. Tissue sections from all cases were hybridized with radiolabeled riboprobes for the presence of both mouse and human c-ets 1 mRNA. Tumor cells were labeled with the human c-ets 1 probe, whereas neovascular and inflammatory tissues were of mouse origin.Conclusions:The finding that vascular but not tumor cells are of host origin supports the model of tumor-induced vascularization via a mechanism of tumor cell-derived cytokinemedicated pathogenesis.Journal of Human Virology 1999;2:315-317 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID