Assays for antiviral drug resistance.
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Antiviral Agents↗
Biomedical subjects
S A Spector
Publications and source records attributed to S A Spector.
Molecular detection of human cytomegalovirus and determination of genotypic ganciclovir resistance in clinical specimens.
The data presented in this article demonstrate how the polymerase chain reaction (PCR) can be used to detect human cytomegalovirus (HCMV) DNA in the plasma and cerebrospinal fluid (CSF) of infected individuals. Detection of HCMV DNA in plasma of transplant recipients and persons infected with human immunodeficiency virus identifies people with acute visceral disease and those at highest risk for development of HCMV disease. The detection of HCMV DNA in CSF is of particular help in identifying persons with HCMV-related central nervous system disease. In addition, specific mutations within the UL97 region, which encodes for a HCMV protein kinase, have been found to confer ganciclovir resistance and can be detected in plasma and CSF by direct sequencing of PCR products. These data will help provide tools for clinicians to better diagnose, manage, and treat persons with HCMV disease.
AIDS-Related Opportunistic Infections↗
High-dose nevirapine: safety, pharmacokinetics, and antiviral effect in patients with human immunodeficiency virus infection.
Nevirapine, a potent nonnucleoside reverse transcriptase inhibitor, produces a transient antiviral effect at < or = 200 mg/day due to the selection of resistant virus. To examine if higher levels of nevirapine could produce sustained antiviral activity, its safety, pharmacokinetics, and antiviral activity at 400 mg/day were studied in 21 patients. There was a rapid reduction in immune complex-dissociated p24 antigen and serum human immunodeficiency virus RNA concentration in all patients, and 8 of 10 patients had > 50% reduction at 8 weeks. Nevirapine-resistant virus was isolated from all subjects tested at 12 weeks: The mean plasma trough level (4.0 micrograms/mL [15.8 microM]) exceeded the mean IC50 of resistant virus. Rash developed in 48% of patients and was a dose-limiting toxicity factor in 6. These data suggest that clinical testing of potent antiviral compounds that select for drug-resistant virus is justified to determine if serum levels of drug sufficient to overcome resistant virus can be attained.
Adult↗
Absence of infectious retinitis after injection of human cytomegalovirus into rabbit eyes.
The rabbit model of human cytomegalovirus (HCMV) retinitis was evaluated by preretinal and intravitreal injection of HCMV into rabbit eyes. Ocular disease was evaluated by indirect ophthalmoscopy, histopathology, and immunohistochemistry. Vitritis, optic nerve congestion, multiple small white infiltrates in the cortical vitreous or on the retinal surface, and retinal detachments were seen. Histopathologic examination showed inflammatory cell infiltration in the preretinal vitreous, optic nerve, and transiently in the superficial inner retina. Retinal structure was preserved except for changes in areas of retinal detachment. No necrosis or destruction of the retina was seen. Immunohistochemistry showed no evidence of cytomegalovirus infection. Inoculation of culture medium containing fetal calf serum caused a similar reaction. It is concluded that vitreous and retinal inoculation of HCMV in the rabbit eye caused nonspecific inflammation without evidence of infection, so this is not a suitable model for HCMV retinitis.
Animals↗
Pharmacokinetic, safety, and antiviral profiles of oral ganciclovir in persons infected with human immunodeficiency virus: a phase I/II study. AIDS Clinical Trials Group, and Cytomegalovirus Cooperative Study Group.
A phase I/II study evaluated the pharmacokinetics, tolerability, and antiviral activity of oral ganciclovir in persons infected with human immunodeficiency virus (HIV). Oral bioavailability ranged from 2.6% to 7.3%. The mean maximum serum concentration achieved at 1000 mg every 8 h was 1.11 micrograms/mL, and mean trough level was 0.54 microgram/mL. The time to maximum serum drug concentration was 1.0-2.9 h, with a serum half-life of 3.0-7.3 h, suggesting prolonged oral absorption. Serious adverse events were uncommon. Decreased cytomegalovirus (CMV) shedding was observed from all sites. The median days (by dosage) to retinitis progression assessed by retinal examination after initiation of oral ganciclovir were 62 (1000 mg every 8 h), 148 (500 mg every 3 h), 75 (750 mg every 3 h), 148 (1000 mg every 3 h), and 139 (2000 mg every 8 h). Thus, oral ganciclovir has pharmacokinetic, toxicity, and antiviral profiles that may prove beneficial for both maintenance therapy of CMV retinitis and prevention of CMV disease in HIV-infected persons.
Administration, Oral↗
Virologic characterization of primary human immunodeficiency virus type 1 infection in a health care worker following needlestick injury.
A health care worker (HCW) was infected via needlestick with human immunodeficiency virus (HIV) type 1 from a subject with AIDS who harbored a zidovudine-resistant, syncytium-inducing (SI) HIV strain. The phenotypic characteristics of the HIV-1 isolates obtained from the HCW and markers of virus load were followed for 20 months. Although the HCW was initially infected with an SI strain, within 75 days of infection the isolate became non-SI and remained so for > or = 635 days. Even though the AIDS patient had a zidovudine-resistant virus, the HCW was infected with a zidovudine-sensitive virus. Plasma RNA levels peaked 20 days after infection, declined rapidly within 2 weeks, and remained stable for the duration of follow-up. Similarly, the HCW's CD4 lymphocyte count remained stable throughout the study. Thus, selection for non-SI and zidovudine-sensitive virus occurred in the HCW, who, after initial symptomatic infection associated with high levels of plasma HIV-1 RNA, developed low plasma RNA copy numbers and stable CD4 lymphocyte counts.
Acquired Immunodeficiency Syndrome↗
A randomized trial of the activity and safety of Ro 24-7429 (Tat antagonist) versus nucleoside for human immunodeficiency virus infection. The AIDS Clinical Trials Group 213 Team.
Ro 24-7429, a Tat antagonist, dosed at 75, 150, or 300 mg/day, was compared with nucleoside analogue (zidovudine or didanosine) for 12 weeks in 96 human immunodeficiency virus (HIV)-infected patients to assess safety and activity. The primary adverse effect of Ro 24-7429 was rash, which necessitated treatment discontinuation in 6 of 71 patients. Nucleoside analogue treatment produced an average increase in CD4 cell count of 28 cells/mm3 at week 8 versus a decrease of 27 cells/mm3 in recipients of Ro 24-7429 (P < .001). Serum HIV p24 antigen levels decreased by an average of 111 pg/mL in nucleoside recipients at week 8 compared with an increase of 41 pg/mL in recipients of Ro 24-7429 (P = .007). Nucleoside-treated patients had a mean 0.66 log10 reduction in infectious peripheral blood mononuclear cells, while Ro 24-7429 recipients had a mean 0.02 log10 reduction (P = .02). No dose-response relationships were observed in the Ro 24-7429 groups. In this study, Ro 24-7429 treatment showed no evidence of antiviral activity.
Adult↗
Detection of human cytomegalovirus mutations associated with ganciclovir resistance in cerebrospinal fluid of AIDS patients with central nervous system disease.
To examine the involvement of ganciclovir-resistant strains in the development of central nervous system (CNS) disease caused by human cytomegalovirus (HCMV), 14 AIDS patients with CNS disease caused by HCMV were studied for the presence of HCMV strains with UL97 gene mutations associated with ganciclovir resistance by using amplification and direct sequencing of HCMV DNA in cerebrospinal fluid (CSF). The CSF of all seven patients who had not received ganciclovir prior to the development of CNS disease and four patients who had been receiving the drug for 3 to 8 months contained wild-type UL97 sequences. The CSF of three patients who had received ganciclovir for 12 to 30 months contained HCMV strains with nucleotide changes leading to single-amino-acid substitutions within conserved UL97 sites implicated in nucleotide binding (position 460) and substrate recognition (position 591). Patients containing mutant and wild-type strains revealed a similar spectrum of clinical and histopathologic manifestations. These findings indicate that CNS disease in AIDS patients receiving prolonged ganciclovir therapy can be caused by ganciclovir-resistant HCMV strains. Direct genotypic analysis of HCMV DNA within CSF should help to identify ganciclovir-resistant virus and to guide anti-HCMV therapy.
AIDS-Related Opportunistic Infections↗
Length of incubation time for human immunodeficiency virus cultures.
Qualitative human immunodeficiency virus culture is a slow, labor-intensive, and expensive procedure, yet critical for the diagnosis of infants born to human immunodeficiency virus-seropositive mothers. We report that the cultures can be terminated at day 21 with minimal false-negative results but with considerable savings in both time and money.
Child↗
Human cord blood mononuclear cells are preferentially infected by non-syncytium-inducing, macrophage-tropic human immunodeficiency virus type 1 isolates.
Identification of the factors which impact on the transmission of human immunodeficiency virus type 1 (HIV-1) from an infected mother to her infant is essential for the development of effective strategies to prevent perinatal HIV-1 infection. The current study was designed to determine if unstimulated human neonatal cord blood mononuclear cells (CBMC) differ from adult peripheral blood mononuclear cells (PBMC) in susceptibility to HIV-1 infection. Both cell populations were challenged with two laboratory and two clinical HIV-1 isolates with different phenotypic properties. Infection was evaluated by quantitation of p24 antigen production and p24 antigen expression by an enzyme immunoassay and immunofluorescence, respectively. T-cell markers were determined by flow cytometry. Unstimulated CBMC were preferentially infected by macrophage-tropic, non-syncytium-inducing (non-SI) laboratory and clinical isolates, whereas PBMC were more susceptible to T-lymphotropic, SI HIV-1 strains. The macrophage-tropic strain HIV-1Ba-L replicated to 100-fold higher titers in CBMC than a similar inoculum of the SI isolate HIV-1LAI. The opposite occurred in unstimulated PBMC, which replicated HIVLAI to eightfold higher titers than the macrophage-tropic isolate. These findings indicate that a selection of viral phenotype may occur with unstimulated CBMC displaying a predominant susceptibility to infection by macrophage-tropic, non-SI HIV-1 strains and that this selection may influence mother-infant transmission of HIV-1.
Adult↗
Differential effects of human cytomegalovirus on integrated and unintegrated human immunodeficiency virus sequences.
Human cytomegalovirus (HCMV) has been implicated as a potential cofactor in human immunodeficiency virus type 1 (HIV-1)-related disease. Previously, we reported that HCMV inhibits HIV-1 RNA and protein synthesis in cells productively infected with both viruses but, in transient assays, activates an HIV-1 long terminal repeat-chloramphenicol acetyltransferase (LTR-CAT) construct introduced into the cell by transfection (V. Koval, C. Clark, M. Vaishnav, S. A. Spector, and D. H. Spector, J. Virol. 65:6969-6978, 1991). We show here that HCMV can also activate an infectious proviral HIV-1 genome transiently transfected into a cell. To ascertain whether integration of the HIV-1 provirus plays a role in these differential effects, we generated monoclonal and polyclonal cell lines that each contain a single integrated copy of an HIV-1 LTR-CAT construct and compared the regulatory effects of HCMV and HIV-1 infection in these cells with those occurring in the same type of cell transiently transfected with the HIV-1 LTR-CAT construct. We find that HCMV activates the transfected HIV-1 promoter 230-fold but activates the integrated promoter only 2.8- to 54-fold. In contrast, HIV-1 stimulates the integrated HIV-1 promoter 2,700- to 6,000-fold but stimulates the transfected promoter only 80-fold. Thus, the relative response of the HIV-1 promoter to HCMV and HIV-1 regulatory proteins depends upon whether it is integrated. To determine if HIV-1 gene products are necessary for the HCMV-mediated repression, we constructed cell lines containing two different stably integrated HIV-1 proviruses: one is tat- and nef-minus and transcriptionally inactive, while the other is env- and nef-minus but actively expresses the other HIV-1 gene products. Upon infection with HCMV, HIV-1 antigen production was stimulated from the inactive HIV-1 genome but inhibited from the active genome. We propose that HCMV has two separate effects on HIV-1 replication during a coinfection. One is a slight stimulatory effect which would be undetectable during an active HIV-1 infection, while the other is a net inhibitory effect that is mediated by an interaction between HCMV and HIV-1 gene products.
Cell Line↗
Replication of macrophage-tropic and T-cell-tropic strains of human immunodeficiency virus type 1 is augmented by macrophage-endothelial cell contact.
Macrophages perform a central role in the pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection and have been implicated as the cell type most prominent in the development of central nervous system impairment. In this study, we evaluated the effect of interaction between macrophages and endothelial cells on HIV-1 replication. Upregulation of HIV-1 replication was consistently observed in monocyte-derived macrophages (hereafter called macrophages) cocultured with either umbilical vein endothelial cells or brain microvascular endothelial cells. HIV-1 p24 antigen production of laboratory-adapted strains and patient-derived isolates was increased 2- to 1,000-fold in macrophage-endothelial cocultures, with little or no detectable replication in cultures containing endothelial cells only. The upregulation of HIV-1 in macrophage-endothelial cocultures was observed not only for viruses with the non-syncytium-inducing, macrophage-tropic phenotype but also for viruses previously characterized as syncytium inducing and T-cell tropic. In contrast, cocultures of macrophages with glioblastoma, astrocytoma, cortical neuronal, fibroblast, and placental cells failed to increase HIV-1 replication. Enhancement of HIV-1 replication in macrophage-endothelial cocultures required cell-to-cell contact; conditioned media from endothelial cells or macrophage-endothelial cocultures failed to augment HIV-1 replication in macrophages. Additionally, antibody to leukocyte function-associated antigen (LFA-1), a macrophage-endothelial cell adhesion molecule, inhibited the enhanced HIV-1 replication in macrophage-endothelial cell cocultures. Thus, these data indicate that macrophage-endothelial cell contact enhances HIV-1 replication in macrophages for both macrophage-tropic and previously characterized T-cell-tropic strains and that antibody against LFA-1 can block the necessary cell-to-cell interaction required for the observed upregulation. These findings may have important implications for understanding the ability of HIV-1 to replicate efficiently in tissue macrophages, including those in the brain and at the blood-brain barrier.
Antibodies, Monoclonal↗
Mutations in human cytomegalovirus UL97 gene confer clinical resistance to ganciclovir and can be detected directly in patient plasma.
Specific mutations in the UL97 region of human cytomegalovirus (HCMV) have been found to confer resistance to laboratory-adapted strains subjected to ganciclovir selection. In this study, mutations in the UL97 region of HCMV isolates obtained from patients receiving ganciclovir therapy were examined to determine whether they would confer ganciclovir resistance, and if these mutations could be detected directly in the plasma of AIDS patients with progressive HCMV disease despite ganciclovir treatment. A single nucleotide change within a conserved region of UL97 was found in five resistant isolates, resulting in an amino acid substitution in residue 595: from leucine to phenylalanine in one, and from leucine to serine in four resistant isolates. A sixth resistant isolate demonstrated a single nucleotide change, leading to a threonine to isoleucine substitution in residue 659. The role of the 595 amino acid substitution in conferring ganciclovir resistance was confirmed by marker transfer experiments. In further studies, direct sequencing of HCMV DNA present in plasma obtained from persons with resistant viruses revealed the identical amino acid substitutions in plasma as those present in the cultured viruses. These findings indicate that clinical resistance to ganciclovir can result from specific point mutations in the UL97 gene, and that the emergence of the resistant genotype can be detected directly in patient plasma.
Acquired Immunodeficiency Syndrome↗
Quantitation of human cytomegalovirus (HCMV) DNA in cerebrospinal fluid by competitive PCR in AIDS patients with different HCMV central nervous system diseases.
The current study was designed to quantitate human cytomegalovirus (HCMV) DNA in cerebrospinal fluid (CSF) of persons with AIDS with specific HCMV-related CNS disease. DNA present in CSF obtained from AIDS patients was initially detected by a qualitative PCR procedure and then quantitated using a competitive PCR assay. In a group of 21 AIDS patients with HCMV-related CNS disease, 12 patients with HCMV polyradiculopathy had a mean +/- SEM of 11,982 +/- 4,480 copies/microliters in their CSF compared to 1,747 +/- 929 for 9 patients with HCMV encephalitis p = 0.017). Of the 14 patients with > 1,000 copies/microliters of HCMV DNA in CSF, 11(79%) had HCMV polyradiculopathy including all 3 with > 10,000 copies/microliters. Ganciclovir treatment of 3 patients with HCMV-related CNS disease was associated with a decline in HCMV DNA detectable within CSF. These data indicate that quantities of HCMV DNA in CSF are higher in persons with HCMV-related polyradiculopathy than encephalitis, and that quantitation of HCMV DNA can be useful in monitoring antiviral therapy.
AIDS-Related Opportunistic Infections↗
Effect of choline supplementation on fatigue in trained cyclists.
The availability of choline, the precurser of the neurotransmitter, acetylcholine, in the diet is sufficient to provide the body's requirements under normal conditions. However, preliminary evidence indicates that depletion of choline may limit performance, while oral supplementation may delay fatigue during prolonged efforts. A double-blind cross-over design was used to determine the relationship between plasma choline and fatigue during supramaximal brief and submaximal prolonged activities. Twenty male cyclists (ages 23-29) with maximal aerobic power (VO2max) between 58 and 81 ml.min-1.kg-1 were randomly divided into BRIEF (N = 10) and PROLONGED (N = 10) groups. One hour after drinking a beverage with or without choline bitartrate (2.43 g), cyclists began riding at a power output equivalent to approximately 150% (BRIEF) and 70% (PROLONGED) of VO2max at a cadence of 80-90 rpm. Time to exhaustion, indirect calorimetry and serum choline, lactate, and glucose were measured. Increases in choline levels of 37 and 52% were seen within one hour of ingestion for BRIEF and PROLONGED groups, respectively. Neither group depleted choline during exercise under the choline or placebo conditions. Fatigue times and work performed under either test condition for the BRIEF or PROLONGED groups were similar. Consequently, trained cyclists do not deplete choline during supramaximal brief or prolonged submaximal exercise, nor do they benefit from choline supplementation to delay fatigue under these conditions.
Administration, Oral↗
Low prevalence of HIV-1 proviral DNA in peripheral blood monocytes and dendritic cells from HIV-1-infected individuals.
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DNA, Viral↗
Multicenter trial of Towne strain attenuated virus vaccine in seronegative renal transplant recipients.
The Towne strain of attenuated CMV vaccine was compared with placebo in seronegative renal transplants who later received kidneys from seropositive donors. This was a double-blind, randomized, placebo-controlled trial conducted at 3 different institutions. The results were consistent with 2 prior studies, in that whereas mild CMV disease was only slightly and insignificantly reduced in vaccine recipients, severe disease was markedly reduced. In the current study, all 4 severe cases of CMV disease occurred in placebo recipients, for an incidence of 17%, versus 0% in vaccine recipients (P < 0.03). Thus, prior immunization rendered seronegative patients more resistant to the effects of CMV infection.
Cytomegalovirus↗
A controlled trial of intravenous immune globulin for the prevention of serious bacterial infections in children receiving zidovudine for advanced human immunodeficiency virus infection. Pediatric AIDS Clinical Trials Group.
BACKGROUND: Serious bacterial infections are common in children infected with the human immunodeficiency virus (HIV). Studies performed before zidovudine became standard therapy found that intravenous immune globulin decreases the number of serious bacterial infections in these children. We designed a multicenter study to evaluate the efficacy of intravenous immune globulin in children with advanced HIV infection who were receiving zidovudine. METHODS: In a double-blind trial 255 children between 3 months and 12 years of age who had the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex were randomly assigned to receive either intravenous immune globulin (400 mg per kilogram of body weight) (n = 129) or placebo (0.1 percent albumin) (n = 126) every 28 days. All children received 180 mg of zidovudine per square meter of body-surface area orally four times daily. Treatment assignment was stratified according to whether the patients had a history of one or more serious bacterial infections, had previously been treated with zidovudine, or were currently receiving prophylaxis with trimethoprim-sulfamethoxazole. The median length of follow-up was 30.6 months. RESULTS: The estimated two-year rates of serious bacterial infections with confirmed pathogens were 16.9 percent for the immune globulin group and 24.3 percent for the placebo group (relative risk, 0.60; 95 percent confidence interval, 0.35 to 1.04; P = 0.07). The treatment effect was seen primarily among the 174 children who were not receiving trimethoprim-sulfamethoxazole prophylaxis at entry; the estimated two-year rates of infection were 11.3 percent for the immune globulin group and 26.8 percent for the placebo group (relative risk, 0.45; 95 percent confidence interval, 0.22 to 0.91; P = 0.03). For the 81 children who were receiving trimethoprim-sulfamethoxazole prophylaxis initially, the rates were 27.7 percent in the immune globulin group and 17.7 percent in the placebo group (relative risk, 1.26; 95 percent confidence interval, 0.44 to 3.66; P = 0.67). The two-year survival was similar in the two groups: 79.2 percent among immune globulin recipients and 75.4 percent among placebo recipients (P = 0.41). CONCLUSIONS: In children with advanced HIV disease who are receiving zidovudine, intravenous immune globulin decreases the risk of serious bacterial infections. However, this benefit is apparent only in children who are not receiving trimethoprim-sulfamethoxazole as prophylaxis.
AIDS-Related Complex↗