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W Heneine

Publications and source records attributed to W Heneine.

At least 37 records · Page 2Linked to original sources
PubMed2000

Prevalence of mutations associated with reduced antiretroviral drug susceptibility among human immunodeficiency virus type 1 seroconverters in the United States, 1993-1998.

To assess the prevalence of mutations associated with decreased antiretroviral drug susceptibility, specimens were tested from persons infected with human immunodeficiency virus (HIV) during 1993-1998. Subjects were drug naive and were attending sexually transmitted disease clinics in 6 US cities. All were enrolled consecutively and had tested negative for HIV during the 2 years before enrollment. Plasma specimens from patients having >/=1 reverse transcriptase (RT) or primary protease mutation were tested phenotypically with a recombinant virus assay. Of 99 patients, 6 (6%) had mutations associated with zidovudine resistance, 2 (2%) had mutations associated with nonnucleoside RT inhibitor resistance, and 1 (1%) had a primary protease mutation. Overall, the prevalence of resistance-associated primary mutations was 5%, although high levels of decreased drug susceptibility (IC(50)s >/=10 times that of a reference virus) were observed in just 1%. These findings confirm the transmission of these mutations to drug-naive persons.

Adolescent↗
PubMed2000

Simian foamy virus infection among zoo keepers.

We investigated 322 North American zoo workers in an anonymous serosurvey for antibodies to simian foamy viruses to establish the potential risk of zoonotic transmission by these retroviruses. 4 of 133 (3%) individuals who worked specifically with mammals including primates were seropositive, primarily with chimp-like viruses, indicating the importance of work practices to reduce exposure to these agents.

Animal Husbandry↗
PubMed2000

Absence of evidence of infection with divergent primate T-lymphotropic viruses in United States blood donors who have seroindeterminate HTLV test results.

BACKGROUND: Recent identification of divergent simian or primate T-lymphotropic viruses (STLVs; PTLVs) in bonobos (formerly called pygmy chimpanzees; Pan paniscus; viruses: STLVpan-p and STLVpp1664) and a baboon (Papio hamadryas; viruses: STLVph969 or PTLV-L) have raised the possibility of human infection with these viruses. Divergent PTLV-infected primate sera show p24 bands on HTLV-I Western blots (WBs). It was investigated whether infection by divergent PTLV-like viruses could explain a subset of United States blood donors who reacted on HTLV-I EIAs and had indeterminate HTLV-I WBs with p24 bands. STUDY DESIGN AND METHODS: Epidemiologic characteristics of 1889 donors with HTLV-I-indeterminate WBs were compared to those of donors with confirmed retrovirus infections (393 with HIV, 201 with HTLV-I, 513 with HTLV-II) and 1.6 million donors with nonreactive screening tests. To directly probe for infection with divergent PTLVs, 2 HTLV-I-indeterminate donors born in Africa and 269 representative non-African-born donors with p24 bands on HTLV-I WBs (previously shown to be negative for HTLV-I and -II DNA by PCR) were selected for PTLV PCR analysis. DNA from peripheral blood MNC samples was tested for a proviral tax sequence by PCR using generic primers that amplify HTLV-I, HTLV-II, and the divergent PTLVs. Amplified tax sequences were detected by Southern blot hybridization to a (32)P-labeled generic PTLV probe. PCR-positive samples could then be typed by hybridization with virus-specific internal probes that differentiate HTLV-I, HTLV-II, PTLV-L, and STLVpan-p. RESULTS: In the epidemiologic analysis, HTLV-indeterminate status was independently associated with age of at least 25 years (OR = 2.19; 95% CI, 1.93-2.49), black (OR = 3.27; 95% CI, 2.90-3.67) or Hispanic (OR = 1.82; 95% CI, 1.52-2.16) race or ethnicity, and donation at one blood center (Baltimore) (OR = 1. 30; 95% CI, 1.11-1.53). None of the 271 HTLV-I WB-indeterminate samples tested positive by generic PTLV PCR analysis. CONCLUSION: Although the epidemiologic data suggest the possibility of undiagnosed HTLV-I, HTLV-II, or a cross-reactive virus such as PTLV among older, black, and Hispanic blood donors, the PCR data do not support the presence of divergent PTLV infection among US blood donors with HTLV-I-indeterminate results.

Animals↗
PubMed2000

Quantitation of human immunodeficiency virus type 1 group O load in plasma by measuring reverse transcriptase activity.

We have evaluated the use of an ultrasensitive reverse transcriptase (RT) activity assay to monitor plasma viremia in two human immunodeficiency virus type 1 (HIV-1) group O-infected patients treated with stavudine, lamivudine, and indinavir. After a initial decline in RT levels observed at 4 weeks of therapy, RT-based plasma viremia returned to baseline values at 28 or 44 weeks of treatment. The rebound in levels of RT activity was associated with the detection of phenotypic resistance to lamivudine and with the Met184Val mutation. Analysis of RT activity in plasma provides a sequence-independent means of monitoring virus loads in HIV-1 group O-infected patients.

Adult↗
PubMed2000

Evidence of a role for the Q151L mutation and the viral background in development of multiple dideoxynucleoside-resistant human immunodeficiency virus type 1.

The majority of human immunodeficiency virus type 1 (HIV-1)-infected patients treated with zidovudine (AZT) plus zalcitabine (ddC) and didanosine (ddI) develop AZT resistance mediated by mutations such as T215Y and M41L. Only a small proportion of patients develop multiple dideoxynucleoside resistance (MDNR) mediated by the Q151M mutation. To gain insight into the factors responsible for the low frequency of selection of Q151M, we evaluated the replication capabilities of recombinant viruses carrying two possible intermediates (151L or 151K) of the Q151M mutation generated in different reverse transcriptase (RT) genetic backgrounds. The 151L and 151K mutations were introduced by site-directed mutagenesis in RTs from two patient-derived HIV-1 isolates that had either wild type (WT) Q or the Q151M (posttreatment isolate) mutation. For comparison, both mutations were also introduced in a laboratory-adapted HIV-1 strain (HIV-1(HXB2)). Analysis of replication capabilities showed that both 151L and 151K were lethal in RT genetic backgrounds of the WT isolate and in HIV-1(HXB2). In contrast, 151L but not 151K allowed virus replication in RT backgrounds of the posttreatment isolate. Three mutations (V35I, S68G, and I178M) were present in the RT background of the posttreatment isolate but not in the WT isolate. Introduction of S68G in the RT of both the WT isolate and HIV-1(HXB2) partially restored replication capacity of recombinants carrying the 151L mutation. The S68G mutation alone did not confer a significant replicative disadvantage in WT viruses. Like HIV-1(151M), HIV-1(151L) RT was found to have six- to eightfold resistance to AZT-triphosphate (TP), ddA-TP, and ddC-TP, indicating an MDNR phenotype. However, HIV-1(151L) was found to be less fit than HIV-1(151M), which may explain the preferential selection of HIV-1(151M) observed in vivo. The demonstrated ability of HIV-1(151L/68G) to replicate and the associated MDNR suggest that 151L is a potential intermediate of Q151M. The dependence of HIV-1(151L) on other mutations, such as S68G, for replication may explain the low frequency of the Q151M-mediated pathway of resistance.

Amino Acid Sequence↗
PubMed2000

Human immunodeficiency virus type 2 (HIV-2) in Portugal: clinical spectrum, circulating subtypes, virus isolation, and plasma viral load.

The human immunodeficiency virus type 2 (HIV-2) is responsible for 4. 5% of AIDS cases in Portugal. Six HIV-2 subtypes have been described so far, subtype A being proposed as more pathogenic than the rest. The relationship between the clinical status and levels of both cellular and plasma HIV-2 viraemia is not well known, nor their modifications under antiretroviral therapy. Thirty-two consecutive HIV-2 infected persons (17 men, 15 women) attending two different hospitals in Lisbon in 1997 were enrolled prospectively in the study. All but 4 individuals most likely acquired the infection through heterosexual contact. More than half of the study population was of African origin, mainly from Guinea-Bissau. Eleven (34.4%) patients had developed clinical manifestations included within the B or C groups of the CDC classification system for HIV infection, with the rest being asymptomatic. Half of the population was undergoing antiretroviral treatment at the time of the study. HIV-2 subtypes were investigated using a new Nef-based restriction fragment length polymorphism (RFLP) method that allows differentiation of the main two variants, A and B. Plasma viral load was quantified using a new quantitative competitive reverse transcriptase polymerase chain reaction (QcRT-PCR) procedure as well as the Amp-RT assay. Virus isolation was attempted from peripheral blood mononuclear cells. All but one person carried HIV-2 subtype A. Plasma viraemia examined by QcRT-PCR was measurable in 15 (50%) of 30 subjects, yielding in all instances values below 20,000 HIV-2 RNA copies per ml. Plasma RT activity could be detected in only 10 (33%) of 30 subjects, a rate much lower than that seen in HIV-1 infection. Virus was isolated from 16 (53.3%) of 30 patients. A significant correlation was found between CD4+ counts, clinical status, rate of virus isolation, and plasma viral load by both QcRT-PCR and Amp-RT. In conclusion, HIV-2 subtype A is the predominant variant circulating in Portugal among both natives and immigrants. A lower cellular and plasma viral load with respect to HIV-1 was seen in persons without immunosuppression, from whom the rate of virus recovery was extremely low.

Female↗
PubMed1999

Rapid screening of phenotypic resistance to nevirapine by direct analysis of HIV type 1 reverse transcriptase activity in plasma.

Drug susceptibility testing for the clinical management of human immunodeficiency virus type 1 (HIV-1)-infected persons is often curtailed because such testing is expensive and time consuming. We describe a non-culture-based phenotypic assay for the rapid analysis of HIV-1 resistance to nevirapine. The assay measures the susceptibility of plasma reverse transcriptase (RT) activity to inhibition by nevirapine by using the PCR-based Amp-RT assay. Assay validation was made using two reference wild-type (WT) and six other nevirapine-resistant (>100-fold) HIV-1 isolates. Amp-RT IC50 values were found to correlate with those obtained by a conventional replication-based assay. The results also indicated that 50 microM nevirapine can be used in a single screening test to detect nevirapine resistance. Analysis of virus mixtures showed a detection threshold of 10% of nevirapine-resistant HIV-1 in a background of WT virus. To evaluate the assay on clinical samples, 30 plasma specimens collected longitudinally from 4 patients before and after treatment with nevirapine were analyzed, and results were compared with codon 181 genotypes. Preteatment samples and those obtained during the first 6 days of therapy (n = 21) were sensitive to nevirapine, and none had detectable Y181C mutation. Phenotypic resistance was seen in eight samples obtained after 1 week of treatment and was correlated with detection of the Y181C mutation. An increase in the level of phenotypic resistance was seen over time. These data validate this rapid and simple assay for monitoring phenotypic resistance to nevirapine.

Anti-HIV Agents↗
PubMed1999

Search for cross-species transmission of porcine endogenous retrovirus in patients treated with living pig tissue. The XEN 111 Study Group.

Pig organs may offer a solution to the shortage of human donor organs for transplantation, but concerns remain about possible cross-species transmission of porcine endogenous retrovirus (PERV). Samples were collected from 160 patients who had been treated with various living pig tissues up to 12 years earlier. Reverse transcription-polymerase chain reaction (RT-PCR) and protein immunoblot analyses were performed on serum from all 160 patients. No viremia was detected in any patient. Peripheral blood mononuclear cells from 159 of the patients were analyzed by PCR using PERV-specific primers. No PERV infection was detected in any of the patients from whom sufficient DNA was extracted to allow complete PCR analysis (97 percent of the patients). Persistent microchimerism (presence of donor cells in the recipient) was observed in 23 patients for up to 8.5 years.

Adolescent↗
PubMed1999

Polymerase chain reaction assays for the diagnosis of infection with the porcine endogenous retrovirus and the detection of pig cells in human and nonhuman recipients of pig xenografts.

BACKGROUND: Pigs offer an unlimited source of xenografts for humans. However, recipients of pig xenografts are inevitably exposed to the porcine endogenous retrovirus (PERV), which is carried in the pig germline. The ability of PERV to infect human cells in vitro has heightened safety concerns regarding the transmission of PERV to pig xenograft recipients. METHODS: In response to the need to establish laboratory tests for the surveillance of PERV infection, we have developed polymerase chain reaction (PCR) assays to detect PERV pol and gag sequences by using conserved primers and probes. In addition, we have developed a PCR assay to detect pig-specific mitochondrial DNA (mtDNA) sequences as a marker of pig cells. RESULTS: Analysis of assay sensitivities using cloned target copies in a background of human DNA demonstrated a detection threshold of 1, 5, and 1 copy for the PERV gag, pol, and pig mtDNA PCR assays, respectively. All three PCR assays gave negative results on peripheral blood lymphocyte samples from 69 humans, as well as 6 baboons and 6 macaques, demonstrating 100% specificity. The PERV and pig mtDNA assays were integrated into a simple testing algorithm that allows the differentiation between pig cell microchimerism and true xenogeneic infection. To allow for monitoring of PERV expression, a reverse transcriptase-PCR assay was also developed to detect cell-free PERV RNA. CONCLUSION: The use of the diagnostic tests described here will help define the risks of PERV transmission associated with the use of pig xenografts in humans and nonhuman primates.

Animals↗
PubMed1999

Development and validation of a Western immunoblot assay for detection of antibodies to porcine endogenous retrovirus.

BACKGROUND: Reports that pig endogenous retrovirus (PERV) infects human cells in vitro have heightened the importance of molecular and serologic monitoring of xenograft recipients for evidence of infection with PERV. We report the development and validation of a PERV-specific Western immunoblot assay for the diagnostic testing of porcine xenografts recipients. This assay is based upon the serological cross-reactivity observed between PERV variants capable of infecting human cells in vitro and other mammalian C type retroviruses. METHODS AND RESULTS: Strong reactivity between PERV expressing embryonic pig kidney PK-15 cells and antisera raised against whole virus preparations of murine leukemia virus, gibbon ape leukemia virus (GALV), and simian sarcoma-associated virus was demonstrated by an immunofluorescence assay, suggesting specific antigenic cross-reactivity between this group of viruses and PERV. Western immunoblot analysis demonstrated that anti-GALV antisera reacted with three proteins in PK-15 cells having molecular masses of 30, 55, and 66 kDa. Antisera specific for the Gag proteins of either GALV or simian sarcoma-associated virus reacted with the 30-kDa (major) and 55-kDa (minor) proteins present in PK-15 cells and in PERV-infected 293 human kidney cells, likely representing reactivity to the processed and precursor forms of the PERV Gag protein, respectively. No reactivity was seen in uninfected 293 cells. Analysis of plasma samples from 200 United States blood donors and from 58 human immunodeficiency virus-1, 18 human immunodeficiency virus-2, 13 human T-cell lymphotrophic virus-I, 21 human T-cell lymphotrophic virus-II, and 15 cytomegalovirus infected controls were negative. CONCLUSIONS: As this assay is based on PERV antigen derived from infected human cells, it clearly has the capacity to detect a serologic response towards PERV variants that have zoonotic potential and will allow for the accurate determination of PERV-specific seroreactivity in porcine xenograft recipients.

Animals↗
PubMed1999

A rapid non-culture-based assay for clinical monitoring of phenotypic resistance of human immunodeficiency virus type 1 to lamivudine (3TC).

Monitoring for lamivudine (3TC) resistance is important both for the clinical management of human immunodeficiency virus type 1 (HIV-1)-infected patients treated with 3TC and for surveillance of transmission of 3TC-resistant HIV-1. We developed a novel non-culture-based assay for the rapid analysis of phenotypic resistance to 3TC of HIV-1 in plasma. The assay measures the susceptibility of HIV-1 reverse transcriptase (RT) activity to 3TC triphosphate (3TC-TP) in plasma. RT detection was done by the Amp-RT assay, an ultrasensitive PCR-based RT assay. Under our assay conditions, we found that 5 microM 3TC-TP inhibited RT activity from wild-type (WT), zidovudine-resistant, or nevirapine-resistant HIV-1 but not from HIV-1 carrying either the M184V mutation or multidrug (MD) resistance mutations (77L/116Y/151M or 62V/75I/77L/116Y/151M). Mixing experiments showed a detection threshold of 10% 3TC-resistant virus (M184V) in a background of WT HIV-1. To validate the assay for the detection of phenotypic resistance of HIV-1 to 3TC in plasma samples, HIV-1 RT in 30 plasma specimens collected from 15 patients before and during therapy with 3TC was tested for evidence of phenotypic resistance by the Amp-RT assay. The results were compared with those of genotypic analysis. The RT in 12 samples was found to be 3TC sensitive, while the RT in 18 samples had evidence of phenotypic resistance. All 12 samples with 3TC-sensitive RT had WT genotypes at codon 184 and were retrieved before treatment with 3TC. In contrast, all 18 specimens with 3TC-resistant RT were posttherapy samples. This assay provides a simple, rapid, and reliable method for the detection of phenotypic resistance of HIV-1 to 3TC in plasma.

Anti-HIV Agents↗
PubMed1999

Persistent zoonotic infection of a human with simian foamy virus in the absence of an intact orf-2 accessory gene.

Although foamy viruses (FVs) are endemic among nonhuman primates, FV infection among humans is rare. Recently, simian foamy virus (SFV) infection was reported in 4 of 231 individuals occupationally exposed to primates (1.8%). Secondary transmission to spouses has not been seen, suggesting that while FV is readily zoonotic, humans may represent dead-end hosts. Among different simian species, SFV demonstrates significant sequence diversity within the U3 region of the long terminal repeat (LTR) and 3' accessory open reading frames (ORFs). To examine if persistent human SFV infection and apparent lack of secondary transmission are associated with genetic adaptations in FV regulatory regions, we conducted sequence analysis of the LTR, internal promoter, ORF-1, and ORF-2 on a tissue culture isolate and peripheral blood mononuclear cell samples from a human infected with SFV of African green monkey origin (SFV-3). Compared to the prototype SFV-3 sequence, the LTR, internal promoter, and FV transactivator (ORF-1) showed sequence conservation, suggesting that FV zoonosis is not dependent on host-specific adaptation to these transcriptionally important regions. However, ORF-2 contains a number of deleterious mutations predicted to result in premature termination of protein synthesis. ORF-2 codes in part for the 60-kDa Bet fusion protein, proposed to be involved in the establishment of persistent cellular SFV infections. These results suggest that persistent human infection by SFV and reduced transmissibility may be influenced by the absence of a functional ORF-2.

Amino Acid Sequence↗
PubMed1999

Evidence of avian leukosis virus subgroup E and endogenous avian virus in measles and mumps vaccines derived from chicken cells: investigation of transmission to vaccine recipients.

Reverse transcriptase (RT) activity has been detected recently in all chicken cell-derived measles and mumps vaccines. A study of a vaccine manufactured in Europe indicated that the RT is associated with particles containing endogenous avian retrovirus (EAV-0) RNA and originates from the chicken embryonic fibroblasts (CEF) used as a substrate for propagation of the vaccine. We investigated the origin of RT in measles and mumps vaccines from a U.S. manufacturer and confirm the presence of RT and EAV RNA. Additionally, we provide new evidence for the presence of avian leukosis virus (ALV) in both CEF supernatants and vaccines. ALV pol sequences were first identified in particle-associated RNA by amplification with degenerate retroviral pol primers. ALV RNA sequences from both the gag and env regions were also detected. Analysis of hypervariable region 2 of env revealed a subgroup E sequence, an endogenous-type ALV. Both CEF- and vaccine-derived RT activity could be blocked by antibodies to ALV RT. Release of ALV-like virus particles from uninoculated CEF was also documented by electron microscopy. Nonetheless, infectivity studies on susceptible 15B1 chicken cells gave no evidence of infectious ALV, which is consistent with the phenotypes of the ev loci identified in the CEF. PCR analysis of ALV and EAV proviral sequences in peripheral blood mononuclear cells from 33 children after measles and mumps vaccination yielded negative results. Our data indicate that the sources of RT activity in all RT-positive measles and mumps vaccines may not be similar and depend on the particular endogenous retroviral loci present in the chicken cell substrate used. The present data do not support transmission of either ALV or EAV to recipients of the U.S.-made vaccine and provide reassurance for current immunization policies.

Animals↗
PubMed1999

Lack of evidence of conserved lentiviral sequences in pigs with post weaning multisystemic wasting syndrome.

In order to investigate the role of retroviruses in the recently described porcine postweaning multisystemic wasting syndrome (PMWS) serum and leukocytes were screened for reverse transcriptase (RT) activity, and tissues were examined for the presence of conserved lentiviral sequences using degenerate primers in a polymerase chain reaction (PCR). Serum and stimulated leukocytes from the blood and lymph nodes from pigs with PMWS, as well as from control pigs had RT activity that was detected by the sensitive Amp-RT assay. A 257-bp fragment was amplified from DNA from the blood and bone marrow of pigs with PMWS. This fragment was identical in size to conserved lentiviral sequences that were amplified from plasmids containing DNA from several lentiviruses. Cloning and sequencing of the fragment from affected pigs, however, did not reveal homology with the recognized lentiviruses. Together the results of these analyses suggest that the RT activity present in tissues from control and affected pigs is the result of endogenous retrovirus expression, and that a lentivirus is not a primary pathogen in PMWS.

Amino Acid Sequence↗
PubMed1998

No evidence of infection with porcine endogenous retrovirus in recipients of porcine islet-cell xenografts.

BACKGROUND: The study of whether porcine xenografts can lead to porcine endogenous retrovirus (PERV) infection of recipients is critical for evaluating the safety of pig-to-man xenotransplantation. PERV is carried in the pig germline, and all recipients of porcine tissues or organs will be exposed to the virus. METHODS: We studied 10 diabetic patients who had received porcine fetal islets between 1990 and 1993, looking for evidence of PERV infection by using PCR serology, PCR, and reverse transcriptase assays. Prolonged xenograft survival (up to a year) was confirmed in five patients by porcine C-peptide excretion and detection of pig mitochondrial DNA (mtDNA) in serum. FINDINGS: Despite the evidence for extended exposure to pig cells and despite concomitant immunosuppressive therapy, we were unable to detect markers of PERV infection in any patient. Screening for two PERV sequences in peripheral blood lymphocytes collected 4-7 years after the xenotransplantation was negative. Markers of PERV expression, including viral RNA and reverse transcriptase, were undetectable in sera from both early (day 3 to day 180) and late (4-7 years) time points. Western blot analysis for antibodies was consistently negative. INTERPRETATION: These results suggested the absence of PERV infection in these patients. Also this study establishes a minimum standard for post-transplant surveillance of patients given porcine xenografts.

Adult↗
PubMed1998

Amplification of simian retroviral sequences from human recipients of baboon liver transplants.

Investigations into the use of baboons as organ donors for human transplant recipients, a procedure called xenotransplantation, have raised the specter of transmitting baboon viruses to humans and possibly establishing new human infectious diseases. Retrospective analysis of tissues from two human transplant recipients with end-stage hepatic disease who died 70 and 27 days after the transplantation of baboon livers revealed the presence of two simian retroviruses of baboon origin, simian foamy virus (SFV) and baboon endogenous virus (BaEV), in multiple tissue compartments. The presence of baboon mitochondrial DNA was also detected in these same tissues, suggesting that xenogeneic "passenger leukocytes" harboring latent or active viral infections had migrated from the xenografts to distant sites within the human recipients. The persistence of SFV and BaEV in human recipients throughout the posttransplant period underscores the potential infectious risks associated with xenotransplantation.

Adult↗
PubMed1998

Identification of a human population infected with simian foamy viruses.

Studying the transmission of simian retroviruses to humans can help define the importance of these infections to public health. We identified a substantial prevalence (4/231, 1.8%) of infection with simian foamy viruses (SFV) among humans occupationally exposed to nonhuman primates. Evidence of SFV infection included seropositivity, proviral DNA detection and isolation of foamy virus. The infecting SFV originated from an African green monkey (one person) and baboons (three people). These infections have not as yet resulted in either disease or sexual transmission, and may represent benign endpoint infections.

Animals↗