ISSN:0889-2229    

DOI:10.1089/aid.1998.14.1

年代:1998

数据来源: MAL

摘要:

ABSTRACTThe Env glycoprotein of human immunodeficiency virus is critical for the pathogenesis of the acquired immunodeficiency syndrome, and has been the prime target for candidate HIV-1 vaccines. Cytolytic T lymphocytes (CTLs) may be important for the immunologic control of HIV infection and HIV-1 Env-specific cytolytic T cells have been isolated from infected individuals and seronegative recipients of HIV-1 vaccines. Most prior studies have used assays that detect Env-specific CTLs directed against standard laboratory viral variants. These studies may be limited because the Env proteins of these laboratory strains (for example, LAI and MN) may differ significantly from the Env proteins from primary HIV-1 strains, and a single amino acid change can abrogate the recognition of HIV-1 Env by some CTL clones. Therefore, this study measured CTL activity directed against HIV-1 Env representing the infected individual's (autologous) HIV-1 viral variants. For two HIV-1-infected individuals, recombinant vaccina viruses expressing cloned HIV-1envgenes were constructed. Using anin vitrostimulation method, strain-specific CTL activity directed against autologous HIV-1 Env was detected in both individuals. From one subject, strain-specific CTL clones directed against autologous and HIV-1LAIEnv were characterized. Therefore, some infected individuals have Env-specific CTLs directed against autologous strains of HIV-1. Detection and characterization of autologous Env-specific CTL activity may have important implications relative to the current HIV-1 vaccine development strategies focusing on Env derived from laboratory strains of HIV-1.

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.3

年代:1998

数据来源: MAL

摘要:

ABSTRACTWe report the first case of mother-to-infant transmission and follow-up for an HIV-1 group O virus from Cameroon. Isolates were obtained from the mother at delivery and from the child at birth and when 16 and 30 months old. We analyzed the viral evolution within mother and child by examining 51 sequences spanning C2V3 regions of the viral envelope gene. The mother carried two genotypes, v1 and v2. The genotype v1 was dominant in the child at birth, and persisted as a minor genotype at age 30 months. The genotype v2 was absent in the child sequences. The variability of the nucleotide sequences of the isolates from the child increased with age from 0.8 to 6%, and a novel genotype (v3) appeared at age 30 months. The nonsynonymous-to-synonymous mutation ratio increased with the age of the child, from 0.75 at birth to 1.86 at 30 months, indicating a high rate of fixation of amino acid changes in the child. The overall pattern was similar to that reported by Ganeshanetal.1(J Virol 1997;71:663–677) for group M viruses infecting child with a slow-developing form of the diseas

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.15

年代:1998

数据来源: MAL

摘要:

ABSTRACTHIV type 1 viral quasispecies were amplified by polymerase chain reaction (PCR) in the hypervariable V3 region of gp 120 from six different regions of the brain (right and left frontal; right and left parietal; and right and left occipital) and from the peripheral blood mononuclear cells (PBMCs) of a patient who died of AIDS dementia complex (ADC). Cloning and sequencing of the entire V3 region suggested the presence of genetically unique sequences in different regions of the brain. In contrast, the blood-derived viral quasispecies carried homogeneous sequences that were characterized by a single octapeptide crest motif (HLGPGSAF), a motif important in viral fusion. The brain-derived viral strains showed extensive sequence heterogeneity and the presence of seven different octapeptide and four different tetrapeptide crest motifs (HIGPGRAF, RIGPGRAF, HIGPGSAI, HLGPGSAF, HIGPESAI, HLGPESAI, and YLRPGSAF). In addition, the brain-derived strains were also characterized by variable net V3 loop charge and hydrophilicity, along with distinct amino acid changes specific to different brain regions. Together, the sequence and phylogenetic analyses are unique in identifying the complexity of a viral quasispecies and its independent regional evolution within the brain compartment. Uniquely divergent viral strains were identified in the frontal regions and their presence was further supported by the presence of multinucleated giant cells (characteristic of HIV encephalopathy) predominantly in the left and right frontal regions. In summary, these analyses suggest that genetically different populations of HIV-1 may be present in different brain compartments and confirm that specific neurotropic variants may exist.

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.25

年代:1998

数据来源: MAL

摘要:

ABSTRACTWe previously described that V3 loop derived from the HTLV-III BH10 clone V3-BH10 markedly suppressed IL-2-driven T cell proliferation and produced G1arrest of the cells. Here, we tested the effect of V3-BH10 on the molecules that are involved in transition from the G1to S phase of the cell cycle. The effect of V3-BH10 on the IL-2-induced expression of G1cyclins, Cdk inhibitors, and phosphorylation of retinoblastoma protein (pRb) was tested by immunoblotting, using the IL-2-dependent CD4-positive cell line Kit 225. Furthermore, IL-2-dependent kinase activity of the cyclin E–Cdk2 complex was investigated with histone H1 as a substrate. V3-BH10 reduced the IL-2-dependent expression of cyclin E, but not that of cyclin D and Cdk inhibitors such as p21 and p27. As the result of reduction of cyclin E, histone H1 kinase activity of the cyclin E–Cdk2 complex was markedly reduced even in the presence of rIL-2, followed by incomplete phosphorylation of pRb. The reduction in hyperphosphorylation of pRb by V3-BH10 led to G1arrest of the cell cycle. Thus, V3-BH10 induced G1arrest in IL-2-dependent cell cycle progression by reducing cyclin E expression, which may be one of the mechanisms underlying the dysfunction of T cells in HIV-1-infected peo

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.31

年代:1998

数据来源: MAL

摘要:

ABSTRACTTransition from latency to active replication is a crucial stage for the process of human immunodeficiency virus type 1 (HIV-1) infection and life cycle. HIV-1 replication in latently infected cells can be strongly induced by the cytokine tumor necrosis factor α (TNF-α) and the proliferation-arresting chemical sodium butyrate (NaB). We have investigated the ability of the drug 9-nitrocamptothecin (9NC), a potent cellular topoisomerase I (topo I) inhibitor currently in clinical trials in cancer patients, to regulate HIV-1 replication in latently infected lymphocytic ACH-2 cells on reactivation with either TNF-α or NaB. Treatment of ACH-2 cells with 9NC alone resulted in increased levels of viral transcripts, while there was a slight reduction or no change in the levels of host cell transcripts. However, pretreatment of ACH-2 cells with 9NC inhibited TNF-α-induced extracellular HIV-1 p24 levels up to ∼95% and nearly 80% of the cell-associated viral RNAs. The quantitative decrease in viral products was concomitant with a decrease in cellular gene expression and induction of apoptosis in the host cells. 9NC blocked the infected cells at the boundary of the S and G2 phases, resulting in an accelerated apoptosis that was further enhanced with TNF-α treatment. Similar results were observed following concurrent exposure to TNF-α and 9NC, but 9NC failed to inhibit upregulation of HIV-1 mRNA in ACH-2 cells exposed to TNF-α before 9NC treatment. Further, 9NC had no inhibitory effect on NaB-induced apoptosis and upregulation of HIV-1 mRNA expression regardless of whether 9NC and NaB were used concurrently or in various treatment sequences. In uninfected lymphocytic CEM cells derived from a common parental cell line, a slight downregulation of cellular gene expression was detected along with low-level apoptosis. These results demonstrate that 9NC impairs TNF-α-induced, but not NaB-induced, HIV-1 activation, and suggest a means of inhibiting active HIV-1 viremia arising as a result of elevated TNF

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.39

年代:1998

数据来源: MAL

摘要:

ABSTRACTIn Africa the highest HIV infection rate has been reported among female commercial sex workers (CSWs) who are at increasing risk of acquiring and transmitting HIV infection. In October 1995, 176 CSWs were studied in Bamako, the capital city of Mali. The ages of the CSWs ranged from 15 to 50 years old (mean, 28.8 years). Only 20.45% of the 176 CSWs were Malian; the majority were from Nigeria (32.9%) and Ghana (31.8%), and the remaining were from other African countries. Forty-one percent were active for less than 1 year as a commercial sex worker, and the length of prostitution for the remaining women ranged from 1 to 15 years (mean, 2.76). A total of 81 (46.02%) of the 176 CSWs were positive for HIV antibodies; 63 (35.8%) were HIV-1 positive, (3.9%) were HIV-2 positive, 11 (6.2%) had antibodies to HIV-1 and HIV-2, and none of them had antibodies to group O viruses. For all HIV antibody-positive samples, PBMCs were separated and genetic subtypes of HIV-1 were determined using the heteroduplex mobility assay (HMA), with ED5-ED12 as outer and ES7-ES8 as inner primers. Among the 66 HIV-1 strains characterized, 53 (80.3%) were subtype A, 2 (3.1%) belonged to subtype C, 1 (1.5%) belonged to subtype D, and 10 (15.1%) were identified as subtype G. Among the 10 subtype G strains, 8 were obtained from women who were very recent CSWs, with an activity of 1 year or less, assuming that there is a high probability that these infections occurred recently. Genetic subtypes of five HIV-2 viruses were determined by sequencing of theenvand/orgaggenes followed by phylogenetic analysis, and all of them belonged to subtype A. Comparison of HIV-1 and HIV-2 seroprevalence data from our study with previous data from Mali shows a significant rise in HIV-1 prevalence and a significant decrease in HIV-2 prevalence and confirms similar trends observed in neighboring countries. We have found four different genetic subtypes of HIV-1; however, subtype A is predominant and accounts for 80% of the cases and 15% of the HIV-1 infections were subtype G. It is important to continue the surveillance of subtypes on a systematic basis in order to see to what extent the proportions of the different subtypes will change over time.

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.51

年代:1998

数据来源: MAL

摘要:

ABSTRACTHIV-2 downregulates HIV-1 in human primary peripheral blood mononuclear cells (PBMCs). Although the effect of HIV-2 on HIV-1 in human CD4+T cell lines was previously reported, the present observations with PBMCs are a necessary demonstration before considering animal model and clinical studies. Notably, the downregulation was observed with at least three phenotypically different HIV-1 proviruses and three different HIV-2 proviruses and was independent of the mode of introduction of the proviruses. HIV-2 inhibited both the production of extracellular HIV-1 p24 antigen and intracellular viral RNA, suggesting the involvement of transcriptional downmodulation. Some of the defective HIV-2 proviruses also inhibited HIV-1. In some cases, these defects were transcomplemented by the corresponding HIV-1 gene products, emphasizing cross-regulation between the two viruses. The phenotype of one of the mutant HIV-2 proviruses suggested that the posttranscriptional effects may also occur. In addition to the possible HIV-2 suppression of HIV-1in vivoby cross-protective immune mechanisms, intracellular inhibition, noted here, may be another line of defense. We have proposed that the inhibition may be the result of competition between HIV-1 and HIV-2 for cellular factors, possibly involving the long terminal repeats (LTRs). For safety reasons, it may be advantageous to use subunits of HIV-2 for vaccines and gene therapy. HIV-2, specifically noncytopathic HIV-2, could be viewed as an attenuated HIV-1 vaccination model. HIV-2-derived gene transfer vectors may not only be inhibitory themselves but also allow for the insertion of additional protective genes to aim at multiple targets in the HIV-1 life cycle, thus curtailing the evolution of escape mutants.

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.59

年代:1998

数据来源: MAL

摘要:

ABSTRACTA λ phage clone containing a full-length HIV-2 provirus, designated HIV-2KR, was obtained from the genomic DNA of Molt4 clone 8 (Molt4/8) lymphoblastic cells infected with the HIV-2PEI2strain. HIV-2KRis genetically distinct from known HIV-2 isolates, possessing both a unique deletion in the LTR promoter region, and a long rev reading frame. It is replication competentin vitroafter transfection into Molt4/8 cells, replicates in a variety of established human T lymphoblastic (Molt-3, Molt4/8, SupTl, H9, C8166) and myelomonocytic (U937) cell lines, and displays prominent cytopathic effects on infection of Molt4/8 cells, reflecting usage of both CCR5 and CXCR4 coreceptors. In addition, HIV-2KRwas found to be infectious for human andMacaca nemestrinaperipheral blood lymphocytes, and primary human monocyte-macrophage cultures. Intravenous inoculation of cell-free virus intoM. nemestrinaresulted in infection characterized by transient, low-level viremia and modest temporary decline in CD4 lymphocyte numbers, making HIV-2KRthe first HIV-2 molecular clone reported to be infectious for this primate species

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.65

年代:1998

数据来源: MAL

摘要:

ABSTRACTWe have previously shown that baboons (Papio cynocephalus) can be persistently infected with HIV-2 and some baboons progress to an AIDS-like disease with a CD4+T cell decline, cachexia, alopecia, and Kaposi's sarcoma-like fibromatosis. In this study, we found that a new virus isolate, HIV-2UC12, replicated to high levels in baboon peripheral blood mononuclear cells (PBMCs)in vitro. Three baboons were subsequently inoculated and had plasma viral RNA loads that peaked between 15,000 and 7000 copies/ml at 2 weeks postinfection. Virus was isolated from the PBMCs for up to 6 months. Although PBMCs were subsequently virus culture negative, virus could be recovered from the spleen, lymph nodes, and tonsils, indicating that HIV-2 was sequestered within these lymphoid tissues. HIV-2-associated pathology included follicular lysis, vascular proliferation, and lymphoid depletion. This study indicated that HIV-2uCi2infection in baboons can cause HIV-associated pathological abnormalities within the lymphatic tissues and that the high level of HIV-2UC12replicationin vitrowas not predictive of replicationin vivo.

ISSN:0889-2229    

DOI:10.1089/aid.1998.14.79

年代:1998

数据来源: MAL