Western blot seroindeterminate individuals for human T-lymphotropic virus I/II (HTLV-I/II) in Fortaleza (Brazil): a serological and molecular diagnostic and epidemiological approach.

How to handle Western blot (WB) seroindeterminate individuals for Human T-lymphotropic Virus 1/2 (HTLV-1/2) constitutes a challenge for blood banks and families. We made a cross-sectional study of 191 enzyme linked immunoassay (EIA) reactive individuals from the hematological center (HEMOCE) of Fortaleza (Brazil), examining their serological (WB) and molecular (PCR) diagnosis, and demographic profiles, as well as a possible association of their condition with other infectious pathologies and risk factors. Ethical institutional approval and personal consent were obtained.

A combination of poor adherence and a low baseline susceptibility score is highly predictive for HAART failure.

The relationship between adherence, virological response to highly active antiretroviral therapy (HAART) and the presence and development of genotypic resistance was assessed in 41 HIV-infected patients on HAART. Four adherence parameters (drug taking adherence, dosing adherence, timing adherence and drug holidays) were scored prospectively using electronic event monitoring. Genotypic resistance at baseline and after therapy failure was scored retrospectively and a genotype-based susceptibility score was calculated.

Initiation of HAART in drug-naive HIV type 1 patients prevents viral breakthrough for a median period of 35.5 months in 60% of the patients.

The introduction of potent combinations of antiviral drugs is a major breakthrough in the treatment of HIV. We investigated the long-term virologic outcome and the development of resistance after initiating highly active antiretroviral therapy (HAART) in drug-naive patients in daily clinical practice. Twenty-five treatment-naive HIV-1 patients were started on HAART.

Prevalence of genotypic resistance among antiretroviral drug-naive HIV-1-infected patients in Belgium.

Objectives: To estimate the prevalence and the evolution over time (1995-1998) of genotypic resistance to antiviral drugs in antiretroviral drug-naive HIV-1-infected patients in Belgium.

Design: Belgian Aids Reference Laboratories provided retrospective samples and clinical data from antiretroviral drug-naive HIV-1-infected patients who visited the hospital for the first time in 1995 (n=45), 1997 (n=75) and 1998 (n=111). Genotypic resistance to the three available classes of drugs was monitored using the Line Probe Assay (Innogenetics, Gent, Belgium).

The Jezierski papers: live polio vaccine development in colobus monkey cells but not chimpanzee cells in the Belgian Congo, 1952-1958.

A reading of ten relevant papers by Alexandre Jezierski provides evidence for the only attempt in Central Africa to develop a live oral polio vaccine (OPV) from growing reference wild polio strains to 210 passages in colobus monkey tissue culture, and experimental administration to about 25 humans. Chimpanzees were used as a human model, but their tissues or kidneys were absent from the passage and production line of the proposed vaccine. Thus, the implication published by Hooper that Jezierski had produced a candidate OPV that might have contained chimpanzee viruses, possibly simian immunodeficiency virus cpz or the precursor of human immunodeficiency virus-1 group M, is incorrect.

Postscript relating to new allegations made by Edward Hooper at The Royal Society Discussion Meeting on 11 September 2000.

At The Royal Society Discussion Meeting, Origins of HIV and the AIDS epidemic, which this issue records, Edward Hooper added two new 'smoking guns' to the accusations published previously in The river. These were proposed as conclusive evidence for the hypothesis that simian immunodeficiency virus-contaminated CHAT polio vaccine caused the HIV-1 group M epidemic. We have investigated the facts in relation to these 'smoking guns'.

Mutations in the non-nucleoside binding-pocket interfere with the multi-nucleoside resistance phenotype.

Objectives: To investigate the genotypic and phenotypic effects of in vitro resistance selection with lamivudine and/or the second generation non-nucleoside reverse transcriptase inhibitor (NNRTI) quinoxaline HBY097 using HIV-1 isolates carrying the multi-nucleoside resistance pattern linked to the Q151M mutation.

Methods: Virus strains were selected in C8166 cells in the presence of increasing concentrations of lamivudine or HBY097. In parallel control experiments, the virus was cultured in C8166 cells in the absence of drugs.

Presence of 2',5'-Bis-O-(tert-butyldimethylsilyl)-3'-spiro-5"-(4"-amino-1",2"-oxath iole-2",2"-dioxide) (TSAO)-resistant virus strains in TSAO-inexperienced HIV patients.

HIV-1 samples from six patients undergoing diverse anti-HIV therapies possessed the E138A mutation in their reverse transcriptase (RT) genome. Patients were receiving the following therapies: TIBO monotherapy (one patient); zidovudine plus didanosine combination therapy (one); zidovudine monotherapy (one); sequential therapy with zidovudine, then stavudine and finally zalcitabine plus didanosine (one); and two were drug naive. E138K, not E138A, is a known TSAO-specific resistance mutation, emerging under selective pressure in vitro.

In vitro evaluation of the effect of temporary removal of HIV drug pressure.

We tried to establish whether MT-4 cells that were infected with HIV-1(HTLV-III(B)) at a high multiplicity of infection (m.o.i.

Phenotypic assays and sequencing are less sensitive than point mutation assays for detection of resistance in mixed HIV-1 genotypic populations.

The sensitivity and discriminatory power of the 151 and 215 amplification refractory mutation system (ARMS) were evaluated, and their performance for the detection of drug resistance in mixed genotypic populations of the reverse transcription (RT) gene of HIV-1 were compared with T7 sequencing, cycle sequencing, the line probe assay (LiPA) HIV-1 RT test, and the recombinant virus assay (RVA). ARMS and the LiPA HIV-1 RT test were shown to be able to detect minor variants that in particular cases comprised only 1%. T7 sequencing on an ALF semiautomated sequencer could correctly score mixtures only when variants were present at 50%.

Baseline HIV type 1 genotypic resistance to a newly added nucleoside analog is predictive of virologic failure of the new therapy.

We evaluated the predictive value of baseline HIV-1 genotypic resistance mutations for failure of a nucleoside reverse transcriptase inhibitor (NRTI) containing therapy. The change in therapy of 88 HIV-1-infected patients was analyzed retrospectively, relating the genotypic resistance profile at baseline to the evolution of viral load and CD4+ T cell counts. Genotypic resistance at baseline and at 6 months was evaluated with the LiPA HIV-1 RT, which detects mutations at codons 41, 69, 70, 74, 184, and 215.

Tempo and mode of human and simian T-lymphotropic virus (HTLV/STLV) evolution revealed by analyses of full-genome sequences.

We investigated the tempo and mode of evolution of the primate T-lymphotropic viruses (PTLVs). Several different models of nucleotide substitution were tested on a general phylogenetic tree obtained using the 20 full-genome HTLV/STLV sequences available. The likelihood ratio test showed that the Tamura and Nei model with discrete gamma-distributed rates among sites is the best-fitting substitution model.

Evaluating Clinical Isolates for Their Phenotypic and Genotypic Resistance Against Anti-HIV Drugs.

The high replication rate of HIV, together with the low fidelity of its reverse transcriptase, provides the virus with an unprecedented genomic flexibility. This allows a fast adaptation to selective pressure, including antiviral drugs, resulting in the development of drug-resistant strains. The present improvements in the treatment of AIDS patients are at least partly owing to antiviral therapy.

High prevalence of GB virus C/hepatitis G virus in Kinshasa, Democratic Republic of Congo: a phylogenetic analysis.

A prevalence of 10.3% of GB virus C (GBV-C)/hepatitis G virus (HGV) carriers was found in 97 pregnant women from Kinshasa, Congo (formerly Zaire), while prevalences of 1%, 4.1%, and 0% were found for hepatitis C virus, human immunodeficiency virus, and human T-lymphotropic virus respectively.

Resistance of the human immunodeficiency virus to the inhibitory action of negatively charged albumins on virus binding to CD4.

Negatively charged albumins (NCAs) have been identified as potent inhibitors of HIV-1 replication in vitro. Time of addition studies suggest that succinylated and aconitylated human serum albumin (Suc-HSA and Aco-HSA) act at an early stage of the virus life cycle, and surface plasmon resonance (BIAcore) experiments have confirmed a direct interaction of NCAs with HIV-1 gp120. Resistance to Suc-HSA and Aco-HSA was analyzed by characterizing HIV-1 variants that were selected in cell culture after serial passage of the NL4-3 strain in the presence of the compounds.

Different population dynamics of human T cell lymphotropic virus type II in intravenous drug users compared with endemically infected tribes.

The phylogeny of human T cell lymphotropic virus type II (HTLV-II) was investigated by using strains isolated from Amerindian and Pygmy tribes, in which the virus is maintained primarily through mother-to-child transmission via breast-feeding, and strains from intravenous drug users (IDUs), in which spread is mainly blood-borne via needle sharing. Molecular clock analysis showed that HTLV-II has two different evolutionary rates with the molecular clock for the virus in IDUs ticking 150-350 times faster than the one in endemically infected tribes: 2.7 x 10(-4) compared with 1.

The discovery of two new divergent STLVs has implications for the evolution and epidemiology of HTLVs.

We have isolated and characterised two divergent simian T-lymphotropic viruses (STLV), not belonging to the established human and simian T-lymphotropic virus lineages HTLV-1/STLV-1 and HTLV-2. STLV-L, from an Eritrean sacred baboon (Papio hamadryas), has been typed as a third type of simian T-lymphotropic virus, distinct from HTLV-1/STLV-1 and HTLV-2. The other virus, isolated from Congolese bonobos (Pan paniscus), is a distinct member of the HTLV-2 clade and has been designated STLV-2.

Activity of non-nucleoside reverse transcriptase inhibitors against HIV-2 and SIV.

Background: After the initial discovery of 1-(2-hydroxyethoxymethyl)-6-(phenylthio)thymine (HEPT) and tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-one and thione (TIBO) derivatives, several other non-nucleoside reverse transcriptase (RT) inhibitors (NNRTI), including nevirapine (BI-RG-587), pyridinone derivatives (L-696,229 and L-697,661), delavirdine (U-90152), alpha-anilinophenylacetamides (alpha-APA) and various other classes of NNRTI have been described. The hallmark of NNRTI has been based on their ability to interact with a specific site ('pocket') of HIV-1 RT.

Objective: To investigate whether, in addition to HIV-1, different strains of HIV-2 (ROD and EHO) and SIV (mac251, agm3 and mndGB1) are sensitive to a selection of NNRTI i.

The effect of reconstitution of an Haemophilus influenzae type b-tentanus toxoid conjugate (PRP-T) vaccine on the immune responses to a diphtheria-tetanus-whole cell pertussis (DTwP) vaccine: a five-year follow-up.

Controversial results have been obtained from previous studies on the combined administration of Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-whole-cell pertussis (DTwP) combination vaccines, with regard to possible reciprocal interference between the constituent antigens. To document the priming effect and possible long-term immunogenic interference of PRP-T and DTwP combination vaccines, a randomized, double-blind, controlled study was conducted in Belgium. A total of 168 healthy infants received, at 3, 4 and 5 months of age, DTwP vaccine mixed just prior to injection either with PRP-T vaccine (group A, DTwP//PRP-T, N = 85) or with placebo (group B, DTwP//Placebo, N = 83).

The origin and evolution of human T-cell lymphotropic virus type II (HTLV-II) and the relationship with its replication strategy.

In this review, the origin and evolution of the human T-cell lymphotropic virus type II (HTLV-II) are discussed, with particular emphasis on its high genomic stability. In particular, it appears that the virus originated in the African continent and has been infecting human populations for several thousands of years. The very low divergence accumulated on average between different viral strains during such a long period could be explained by considering that in infected individuals the viral amplification could be due mainly to the clonal expansion of the infected cells, via cellular mitosis, rather than to reverse transcription.

Long-term stability of human immunodeficiency virus viral load and infectivity in whole blood.

Background: We intended to evaluate the stability of human immunodeficiency virus (HIV) type 1 virions in whole blood and in culture medium.

Materials And Method: EDTA whole-blood samples taken from 12 patients were left at room temperature for up to 7 days, and aliquots of a laboratory virus stock spiked in EDTA, in heparinized or in citrated whole blood, with or without the addition of Triton X-100, or spiked in culture medium were left at room temperature for up to 120 days before plasma was separated and frozen at -80 degrees C. Viral load was measured for all frozen plasma samples using different viral load assays.

Priming effect, immunogenicity and safety of an Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular pertussis (DTaP) combination vaccine administered to infants in Belgium and Turkey.

To evaluate the priming effect, immunogenicity and safety of an Haemophilus influenzae type b (Hib) tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular (two component) pertussis (DTaP) combination vaccine, a randomized, comparative study was conducted in two centers, one in Belgium and one in Turkey. A total of 410 healthy infants, 160 in Belgium and 250 in Turkey, randomly received DTaP and PRP-T vaccines in one of three fashions. One group (N = 138) received DTaP and PRP-T vaccines reconstituted immediately prior to injection at 3, 4 and 5 months of age, and are referred to as the combined, short schedule group (Co-S).