ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo develop recombinant single-chain Fv fragments against HIV-1 gp120.MethodsA panel of human monoclonal antibody Fv fragments were generated against the HIV-1 gp120 by affinity selection from an antibody library expressed on the surface of filamentous phage. The library was prepared from peripheral blood lymphocytes of an a symptomatic HIV-1-infected mother with a high neutralization titer. This mother did not transmit HIV-1 to her offspring (non-transmitter). Heavy and light chains were initially amplified separately and combined by splicing by overlap extension to generate Fv fragments.ResultsSeveral clones expressing single-chain Fv fragments bind strongly to HIV-1 gp120 and several were found to neutralize cell-free HIV-1IIIB. Gross epitope mapping suggests that different clones bound to different functional regions on the envelope. The clones also exhibited sequence diversity.ConclusionsThis strategy of cloning resulted in the development of functional human-derived antibody reagents with different anti-HIV-1 biological propertiesin vitro.These recombinant Fv fragments have potential utility as immune reagents, as well as in the design of potential immunotherapeutics. In addition, these antibody reagents may provide information on the relationship between humoral immunity and maternal-fetal (vertical) HIV-1 transmission.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo monitor a patient who presented with symptomatic HIV-1 infection for virological and immunological parameters in relation to the clinical course.MethodsVirological studies included determination of frequency of productively HIV-1-infected peripheral blood mononuclear cells (PBMC) and viral RNA load in plasma and p24 antigenaemia. Immunological studies included the analysis of T-cell subsets, the expression of activation markers, CD45RO and CD45RA antigens, the frequency of cells programmed for death, and T-cell function.ResultsDuring the first week post onset of primary HIV-1 infection symptoms high plasma titres of p24 and HIV-1 RNA were observed. The number of productively HIV-1-infected PBMC peaked, coinciding with CD4+ T lymphocytopaenia, during week 2 when clinical improvement started. CD8+ T lymphocytosis was observed 10 days post onset of clinical symptoms, the expanded cell population being of the CD8+CD38+, CD8+CD27+ and CD8+CD28-phenotype. CD8+ T lymphocytosis was paralleled by a high percentage of cells undergoing programmed cell death onin vitroculture.In vitroT-cell function was severely depressed during the first 10 days post onset of clinical symptoms. Within about 3 weeks, following resolution of clinical symptoms, phytohaemagglutinin-induced proliferation was restored to normal levels while responses to the CD3 monoclonal antibody only showed a partial restoration. During follow-up, concomitant with the rise of activated CD8+ T cells, p24 antigen levels and viral RNA load in serum as well as the number of HIV-producing PBMC steeply declined after 2 weeks.ConclusionThese findings demonstrate HIV-1-induced abnormalities during severe clinical symptoms of primary HIV-1 infection. The subsequent strong immune response, which is believed to be responsible for efficient control of viral replication, appears to precede clinical improvement.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveAntigen-driven B-cell proliferation and maturation occur in germinal centers present in lymphoid tissues. This process is highly dependent on functional interactions between B and T lymphocytes.In vitroactivation of CD40 present on B cells mimics B cell-T cell interactions and allows the proliferation of normal Epstein-Barr virus (EBV)-negative B lymphocytes. In HIV-1-seropositive individuals, B cells become exposed to free viral particles and to infected T lymphocytes while migrating through germinal centers. The effect of HIV-1 viral exposure on CD40-activated B lymphocytes was therefore examined.MethodsFreshly isolated B lymphocytes were culturedin vitrothrough activation of CD40. B-cell proliferation, HIV-1 infectivity and viral production were monitored following B-lymphocyte exposure to HIV-1. In addition, HIV-mediated fusion between infected B cells and uninfected CD4+ T lymphocytes was assessed in a co culture assay.ResultsEBV-negative, CD40-activated human B lymphocytes were directly infected by HIV-1. The infection significantly reduced their proliferation rate. Viral production was detected in B-cell culture supernatant. Numerous fusion events indicated that HIV-1 infection of B lymphocytes could spread to T lymphocytes following HIV-1-mediated fusion of these two cell types.ConclusionIn view of the importance of B cell-T cell interactions in the maintenance of a functional immune system, disruption of B-lymphocyte development could have direct implications on the course of AIDS progression.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo evaluate the effect of liposome encapsulation on thein vitroantiviral efficacy, intracellular uptake andin vivopharmacokinetics of 2‘,3’-dideoxyinosine (ddl).MethodsThe accumulation of free and liposome-encapsulated ddl was determined in murine monocyte-macrophage RAW 264.7 cells and human premonocytoid U937 cells. The antiviral efficacy was evaluated in U937 cells infected with HIVIIIB. Tissue distribution and pharmacokinetics of free and liposomal ddl were determined in female Sprague-Dawley rats following the administration of a single intravenous bolus dose (3mg ddl/kg).ResultsThe entrapment of ddl in liposomes results in a lower drug accumulation in both U937 and RAW 264.7 cells. A lower antiviral efficacy against HIVIIIBreplication in U937 cells was observed on encapsulation of ddl in liposomes. Improved pharmacokinetics were observed on entrapment of ddl in liposomes. Higher drug levels were found in plasma for the liposomal formulation. The systemic clearance of the liposomal drug was 120 times lower than that of free drug. Liposome encapsulation of ddl greatly enhanced the drug accumulation in organs of the reticuloendothelial system.ConclusionThe encapsulation of ddl in liposomes modified the tissue distribution and plasma pharmacokinetics of the antiviral agent resulting in a marked improvement of drug biodisponibility. The antiviral efficacy of liposomal ddl was lower than that of free drug in HIVIIIB-infected U937 cells.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectivesWe examined 96 bronchoalveolar lavage fluid (BALF) specimens from AIDS patients with provenPneumocystis cariniipneumonia (PCP) in order to compare the relationship of organism burden, viability and antigen expression with disease severity at the time of clinical presentation.MethodsTinctorial analysis of BALF specimens with proven PCP using Diff-Quik, cresyl echt violet and erythrosin B stains to evaluate organism burden and viability.P. cariniiantigen examination was performed by Western blot analysis.ResultsP. cariniicluster ratios were more sensitive than cyst counts as an indicator of organism burden, and correlated well with the alveolar-arterial oxygen gradient as a measure of disease severity. Erythrosin B, the vital stain used to measureP. cariniiviability, displayed a wide range of values and provided little useful information. Antigens of 35–45 and 95 kD, which were specific forP. carinii, were found by immunoblot analysis in BALF cellular fraction of most patients with pneumocystosis. By contrast, antigens of 52 and 66 kD, which were found in both BALF supernatant and cellular fractions ofP. cariniipatients and controls, most likely represented albumin and immunoglobulin G heavy chain, respectively, of host origin. The 35–45 kD antigen was found in 88% of the BALF specimens and appeared to represent an important marker ofP. cariniiinfection. The 95 kD antigen was detected in 49% of the specimens.ConclusionsWe conclude that analysis ofP. cariniicharacteristics in BALF specimens of patients with pneumocystis may provide additional information. These data will also be helpful in developing more sensitive assays and in targeting specificP. cariniifactors for future investigation.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo compare the effect of octreotide (a long-acting somatostatin analog) to that of antidiarrheal therapy plus placebo on large-volume refractory AIDS-associated diarrhea.DesignA randomized controlled trial.SettingReferral-based clinic and hospital in a tertiary care center.PatientsTwenty male patients with AIDS and refractory diarrhea, with stool volume > 1000 ml/day who failed to improve after initial supportive management. All patients finished the study.InterventionsPatients were randomly given either octreotide in doses of 100, 200 and 300 μg subcutaneously every 8 h, or high doses of loperamide and diphenoxylate orally plus placebo subcutaneously for 10 days.Main outcome measuresBowel movements and stool volume were registered before and every day after treatment by the patients themselves and the nursing personnel.ResultsPatients from both groups were similar for age, time of AIDS diagnosis, duration of diarrhea and etiology. Baseline mean bowel movements per day (9.4 ± 2.8 in the octreotide group versus 10 ± 3.1 in controls) and baseline mean stool volume (2753 ± 840 versus 2630 ± 630 ml/day, respectively) were similar in both groups before therapy (P < 0.05). Mean bowel movements per day after 10 days of therapy was 2.1 ± 1.6 in the octreotide group versus 7 ± 3 in controls (P< 0.05). Mean stool volume after 10 days of therapy was 485 ± 480 in the octreotide group versus 1080 ± 420ml/day in controls (P<0.05). Complete response (stool volume < 250 ml/day) was observed in two patients from the octreotide group and none from controls; partial response (decrease >50% in stool volume) in four and two; and no response (decrease < 50% or no change) in four and eight (P<0.05), respectively. Side-effects occurred in eight out of 10 octreotide patients and three out of 10 controls (P<0.05), but none were significant to result in discontinuation of medication.ConclusionOctreotide proved to be superior to conventional therapy in this short-term treatment of large-volume refractory AIDS-associated diarrhea.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveCytokine dysregulation has been implicated in AIDS pathogenesis and the gastrointestinal tract, containing approximately 40% of the body's lymphoid tissue, is likely to act both as a reservoir of viral infection and a site for immune dysregulation. In this study evidence of cytokine dysregulation in intestinal mucosa has been sought using the reverse transcriptase polymerase chain reaction (RT-PCR) to amplify cytokine mRNA.MethodsRT-PCR was performed on intestinal biopsies obtained from 50 HIV-infected patients and 31 controls. Tissue was obtained at diagnostic endoscopy and total RNA extracted using an RNAzol technique. Following RT, cDNA was amplified using primers specific for β-actin, interleukin (IL)-1β, tumour necrosis factor (TNF)-α, interferon (IFN)-γ, IL-2, IL-4, IL-10 and IL-13.ResultsThere was a significant increase in the expression of the proinflammatory cytokines IL-1β and IFN-γ in the HIV-infected compared with the control small intestinal samples (P<0.01). IL-10 was significantly reduced in the respective groups' large intestine (P<0.02). The expression of IL-2 was also reduced in both the small and large intestinal HIV samples although this was not significant. IL-13 mRNA was only detected in one control patient.ConclusionsDysregulation of cytokine gene expression occurs in the intestinal mucosa of patients with HIV infection and is characterized by increased expression of proinflammatory cytokine mRNA. Further studies are needed to localize the cellular origin of such dysregulation and to quantify the degree of abnormality.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo study progression of HIV infection in individuals who are free of AIDS-defining clinical disease with CD4+ cell counts < 200 x 106/l.DesignProspective and nested case-control study.SettingAmsterdam cohort study on HIV infection, The Netherlands.ParticipantsProspective study: 148 asymptomatic HIV-infected individuals with < 200 x 106/l CD4 + cells. Nested case-control study: 58 men with AIDS-free follow-up more than 2 years after CD4 count <200 x 106/l, compared with 63 who progressed to AIDS within 2 years.Main outcome measuresProgression to AIDS according to the 1987 Centers for Disease Control and Prevention case definition and death.ResultsMedian AIDS-free interval was 22 months, median interval to death 41 months. Presence of syncytium-inducing (SI) HIV variants, HIV p24 antigen, and a low T-cell response after stimulation with phytohaemagglutinin (PHA) were independent predictors of progression to AIDS. Probability of 1 year AIDS-free survival varied between 89 and 38% by the presence or absence of these additional markers. Effect of early treatment could only be detected in men with HIV p24 antigen and SI variants. Case-control analysis showed similar changes over time regarding prognostic markers in both groups although at a lower rate in the AIDS-free men. Eight men remained AIDS-free more than 4 years, SI variants were absent in seven, and all eight were p24-seronegative.ConclusionsHIV-infected individuals can remain disease-free for more than 4 years with very low CD4+ cell counts, provided that they lack other progression markers: SI variants, p24 antigen and a low PHA-induced T-cell reactivity. A beneficiary effect of early treatment may be limited to men with SI variants and/or p24 antigen.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

ObjectiveTo determine the incidence of HIV-1 infection and associated risk factors among young, seronegative, and sexually active women in a mixed rural and urban population in southern Rwanda.DesignA prospective cohort study.MethodsBetween October 1991 and April 1993, we completed a 2-year follow-up survey among HIV-1-seronegative women aged ≤30 years at the time of their initial HIV-1 screening during pregnancy. All women aged ≤25 years and a randomly selected sample of 26–30-year olds were invited to participate from five prenatal clinics in the Butare region. The interview focused on potential risk factors for HIV-1 acquisition during the 2-year interval between blood collection.ResultsOut of 1524 women selected, 1150 (75%) participated in the follow-up survey. The 2-year incidence of HIV-1 infection was 2.7% [95% confidence interval (CD, 1.8–3.9]. Teenage women were at the highest risk (incidence, 10.5%; 95% Cl, 5.2–19.4), with incidence leveling off with increasing age (P<0.001). Women who began sexual activity recently were also at higher risk; the lowest risk category consisted of women aged 26–30 years with 5 or more years of sexual experience. The more urban the geographic residence of the woman, the more likely she was to have acquired HIV-1 infection (P<0.001). In the urban and peri-urban zones, the poorest women were at significantly higher risk of incident HIV-1 infection than women reporting higher household income. In a multivariate analysis, young maternal age, marital status (being single, divorced or widowed), multiple sexual partners, and a history of sexually transmitted diseases remained strongly associated with incident HIV-1 infection. Geographic residence, hormonal contraception, and receipt of injections were no longer significantly associated with incident HIV-1 infection when these other factors were accounted for simultaneously.ConclusionAmong young Rwandan women, the early years of sexual activity are particularly dangerous for acquisition of HIV-1 infection. Interventions should focus on young teenagers before they become sexually active.

ISSN:0269-9370    

出版商:OVID    

年代:1994

数据来源: OVID