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Biomedical subjects

A Goudeau

Publications and source records attributed to A Goudeau.

At least 37 records · Page 2Linked to original sources
PubMed1997

Temporal development and prognostic value of antibody response to the major neutralizing epitopes of gp120 during HIV-1 infection.

Our objective was to analyse the humoral response to the major neutralizing epitopes of gp120. The kinetics of the appearance of antibodies directed to the V3 region (V3 Abs) and antibodies directed to the CD4 binding site (CD4BS Abs) were compared in sequential sera from 20 seroconverters. V3 Abs were titrated using 2 different indirect EIAs with synthetic oligopeptides coated on the solid phase. The sequences of the oligopeptides used were those of the MN isolate or a mixture of the consensus sequences of the 5 major HIV-1 subtypes (A-E). CD4BS Abs titers were determined using an EIA in which serum antibodies compete with a labeled human monoclonal antibody, F105, whose corresponding epitope overlaps the conformation-dependent CD4BS, for binding to purified recombinant gp120 coated on a solid phase. The prognostic value of both antibodies was analyzed in a longitudinal study of 60 HIV-1 infected patients (17 nonprogressors and 43 progressors). Eighty-five percent and 70% of HIV sero-converters were positive for V3 Abs and CD4BS Abs, respectively, during the observation period. V3 Abs were detected first in the majority of the patients (mean delay of appearance, 1.22 +/- 0.96 months vs. 4.81 +/- 2.05 months for CD4BS Abs). Both categories of antibodies appeared simultaneously in 4 patients (20%). No prognostic value could be attributed to these antibodies. Our data confirm that V3 Abs and CD4BS Abs appear with some delay after primary infection, suggesting that they do not play a large or early role in the rapid clearance of viremia in primary HIV-1 infection. These antibodies were not associated with progression to symptomatic infection and are thus of no value for surveillance in HIV-1 infected patients.

Amino Acid Sequence↗
PubMed1996

Diversity of antibody binding to V3 peptides representing consensus sequences of HIV type 1 genotypes A to E: an approach for HIV type 1 serological subtyping.

We investigated whether V3-binding assays might be useful to analyze human immunodeficiency virus type 1 (HIV-1) variants in different geographic regions. We showed that strong cross-reactivity between subtype-specific V3 peptides is almost inevitable in standard indirect enzyme-linked immunosorbent assays (EIA), impairing precise serological subtyping. We therefore developed a subtype-specific EIA (HIV-1 SSEIA) that uses the principle of blocking by an excess of peptide in the liquid phase. Using 231 serum samples collected from HIV-1-infected individuals in 10 different geographical areas from 4 continents, we showed that this approach detected the dominant subtype reactivity in more than 97% of the cases. Internal controls (0 and 100% blocking) were used for every sample such that comparative analysis was possible, independent of both the individual humoral response and the time of collection during the course of infection. This was validated by the excellent concordance of the serological profiles of couples and the temporal stability of the serological profile in individuals. The geographical distribution of the various subtypes in the SSEIA was in agreement with the present knowledge of the distribution of the various genotypes. Although the goal of this study was not an extensive seroepidemiological survey, our results showed that the various profiles in most of the regions were relatively homogeneous, but in central Africa there was a large diversity of serological profiles. Cluster analysis identified a limited number of V3 serogroups of serotypes within the HIV-1 group M. Five serogroups, some of them divided into subgroups, were identified and characterized by a mean serological profile. Our data confirmed that subtypes A and C, although being dissimilar genetic subtypes, present conserved antigenic properties in the V3 region, and that the D subtype is probably the most divergent within the group M (B Korber et al., J Virol 1994;68:6730). Cluster analysis showed a clear correlation between position within the dendrogram and geographical origin of the samples. This is further support for the reliability and thereof the usefulness of the SSEIA. This simple methodology may help facilitate the analysis of the distribution of various HIV-1 subtypes circulating in different populations and regions.

Amino Acid Sequence↗
PubMed1996

Viral safety of a new highly purified factor VIII (OCTATE).

The inactivation of both transfusion-relevant and model viruses by modified pasteurisation (10 hours at 63 degrees C in solution) has been evaluated following the established guidelines of the EU CPMP Ad Hoc Working Party on Biotechnology/Pharmacy. This heat treatment was introduced into the manufacturing process of OCTAVI, a very high purity factor VIII concentrate stabilized only by von Willebrand factor, in the presence of a proprietary mixture of low molecular weight stabilizers. Both enveloped (human immunodeficiency virus, Sindbis virus, herpes simplex virus, pseudorabies virus) and nonenveloped viruses (poliovirus, Coxsackievirus, hepatitis A virus) were inactivated by this heating step by more than 4.7 log10. The combination of the solvent/detergent step used in the manufacture of OCTAVI with this modified pasteurization leads to a double virus-inactivated factor VIII concentrate (OCTATE) with a viral safety distinctly superior to monoinactivated products.

Animals↗
PubMed1996

Analysis of the antibody response in humans with a new inactivated hepatitis A vaccine.

Sera from subjects vaccinated with the Pasteur Merieux (PM) inactivated hepatitis A vaccine (AVAXIM) have been analysed in order: (1) to assess comparability of the results provided by a modified radio-immunoassay (mRIA) in the different laboratories involved in testings of sera during clinical trials and by enzyme-linked immunoabsorbent assay (ELISA) used during development of other inactivated hepatitis A vaccines; (2) to describe the IgM responses elicited by this vaccine compared with one control vaccine [HAVRIX, 720 ELISA antigens units; Smithkline Beecham (SB), Rixensart, Belgium]; (3) to provide comparative data between the PM vaccine and the SB vaccine on neutralizing activities of vaccine-induced antibodies. Vaccine-induced antibody titres evaluated by a mRIA in different laboratories correlated well and validated the comparability of the results obtained in various vaccine trials conducted by PM. Geometric mean titres (GMTs) expressed as milli-international units (mlU/ml) were higher with ELISA especially after the first dose, but seroconversion rates were similar and a good correlation was found between the two assays. IgM vaccine-induced antibodies were detectable in nearly all vaccinated subjects from week 2 after vaccination, with a peak titre between weeks 2 and 4 after the first dose. Comparison of GMTs by the Student Fisher t-test was statistically significant (P < 0.05) only at week 2 with higher titres in PM vaccinees. Neutralizing antibodies were detected after vaccination with the PM inactivated hepatitis A vaccine. The titres gradually increased between the second week after the first dose and the booster dose (week 24). A strong booster effect of the second dose on neutralizing titres was observed. Seroneutralizing titres induced at week 2 in subjects vaccinated with the PM inactivated hepatitis A vaccine were statistically significantly higher (P < 0.05) from those induced by the SB vaccine.

Adolescent↗
PubMed1995

Detection and typing of human papillomaviruses by in situ hybridization with biotinylated oligonucleotide mixtures.

The value of biotinylated oligonucleotide probes for screening and typing by in situ hybridization of the most frequent genital human papillomavirus infections (HPVs 6, 11, 16, 18, 31, and 33) was assessed. Optimal hybridization conditions were defined on a panel of paraffin-embedded tissue sections previously characterized with HPV full genome probes. Mixtures of oligonucleotides rather than single oligonucleotides were used to improve sensitivity and specificity. All HPV-positive specimens were detected by the screening mixture with a sensitivity and specificity similar to that of full genome probes. Typing mixtures were highly specific for each HPV type. This study confirms the potential of oligonucleotide probes for detecting and typing HPV infections.

Biotin↗
PubMed1995

A simple procedure to generate chimeric Pr55gag virus-like particles expressing the principal neutralization domain of human immunodeficiency virus type 1.

The Pr55gag human immunodeficiency virus type 1 (HIV-1) precursor protein that is capable of auto-assembling was used as a carrier for a consensus sequence of the principal neutralization domain (PND) of the HIV-1 envelope. For this purpose, a modified HIV-1 gag gene with deletion of the sequence encoding a previously described p24 epitope (amino acids 196-228 of Pr55gag) was first obtained using PCR with degenerate primers, and then cloned. This deleted gag gene allowed in a second time the insertion of a synthetic oligonucleotide cassette encoding the North American/European consensus PND precisely in place of the p24 epitope. The chimeric gene was then inserted into a baculovirus transfer vector and expressed in insect cells. The construct formed 100-140 nm virus-like particles that were released into the extracellular medium. The use of a serum-free medium that supports growth of insect cells facilitated the downstream purification of the extracellular particles. The chimeric particles were recognized by monoclonal antibodies directed to V3 by Western blot but not by immune electron microscopy, suggesting that, although the inserted sequence was still antigenic it was not exposed at the surface of the particles. The results show the ability of Pr55gag to serve as a carrier for easy insertion, in a precisely defined region, of selected epitopes of gp120 surface envelope protein, and to still auto-assemble in virus-like particles. However, the data indicate that exposed epitopes of the mature p24 protein are not presented similarly in the Pr55 precursor, and therefore that different constructs with various insertions in different places must be generated. Such constructs offer an attractive approach for HIV vaccine development and will need evaluation for both antigenicity and immunogenicity.

Amino Acid Sequence↗
PubMed1995

Direct investigation of protein RNA-binding domains using digoxigenin-labelled RNAs and synthetic peptides: application to the hepatitis delta antigen.

A new method is described for the characterization of RNA binding domains of a protein and applied to the study of the interaction between proteins and nucleic acid of the human hepatitis delta virus (HDV). The method uses synthetic peptides coated onto an ELISA plate and tested for their ability to bind digoxigenin-labelled RNAs. RNA binding is quantified with peroxidase-conjugated anti-digoxigenin. The hepatitis delta antigen (HDAg) is an RNA-binding protein that specifically binds HDV RNAs. In a previous study, it was shown that HDAg sequences corresponding to residues 2-27 and 79-107 bound to both genomic and antigenomic strands. Further investigations are reported on HDAg/HDV RNA binding, using additional HDAg peptides and the full-length HDV genomic and antigenomic strands. In order to validate the method, the efficiency of peptide coating onto the ELISA plate was assessed with human antibodies against HDAg. The two arginine-rich motifs potentially involved in the RNA-binding activity (97-107 and 136-146) were explored and the residues 2-27 and 79-211 were mapped using synthetic peptides. Only peptides corresponding to residues 2-17, 2-27, 79-107 and 84-126 of the HDAg bound to the genomic and antigenomic strands. The second arginine-rich motif represented by peptides 130-144 and 128-152 did not bind to HDV RNAs in this assay. This second arginine-rich domain may be involved in this interaction without a direct ability to bind HDV RNAs.

Amino Acid Sequence↗
PubMed1995

Incidence and prevalence of hepatitis B in France.

Reporting of hepatitis B is not compulsory in France, but it is estimated that 8500-9000 acute cases and 100,000 hepatitis B infections occur every year. Seroprevalence studies have been carried out in selected populations. Every blood donation is screened for HBsAg, alanine aminotransferase elevation and anti-HBc antibody. Prevalence of HBsAg has declined from 13.9 positive donations in 1986 per 10,000 to 5.3 in 1991. In pregnant women, overall seroprevalence is estimated at 0.8-1%, which represents more than 5000 children born each year to carrier mothers. Screening of HBsAg for all women when six months pregnant is now compulsory. Heterosexual patients at STD clinics were shown to have a very high risk of being infected with hepatitis B virus, with a chronic carrier rate of 4-5%. In hospital employees before the introduction of vaccination, the overall incidence of hepatitis B was 100-300 acute cases per 100,000 employees per year. Risk varied according to exposure to blood; the highest incidence was found in nurses in dialysis wards. Vaccination against hepatitis B is now compulsory for all hospital and laboratory workers and medical and paramedical students. In preventive medicine consultants, routine medical check-up showed an overall HBV prevalence of 2.2% and a carrier rate of 0.3% in men and 0.1% in women. Immunization of all newborns and adolescents has recently been adopted in France, vaccination at school of adolescents aged 10-11 years being the main target.

Blood Donors↗
PubMed1995

Characterization of Streptococcus agalactiae strains by multilocus enzyme genotype and serotype: identification of multiple virulent clone families that cause invasive neonatal disease.

The chromosomal genotypes of 277 isolates of 16 serotypes of Streptococcus agalactiae were characterized by analysis of electrophoretically demonstrable allele profiles at 12 metabolic enzyme loci. The collection comprised the type strain and 276 strains recovered from French symptomatic and asymptomatic subjects. Sixty-one distinctive electrophoretic types (ETs), representing multilocus clonal genotypes, were identified. Cluster analysis of the ETs revealed two primary phylogenetic divisions separated by a genetic distance of 0.62, Division I contained 67 isolates which could be assigned to 13 ETs. Twenty-seven of these isolates were from samples of cerebrospinal fluid (CSF) from neonatal meningitis patients. Two ETs, separated by a genetic distance of 0.217, contained 26 of these 27 isolates. Division II contained 210 isolates, of which 27 were isolated from CSF. This division was more polymorphic and included 48 ETs. Spanning a genetic distance of 0.3, three clusters and one ET were identified within this group. Twenty-four of 27 strains isolated from CSF belonged to one cluster, and 19 of them belonged to two adjacent ETs with a genetic distance of 0.083. Fifty-five of the 68 serotype Ia strains and 24 of the 26 serotype Ib strains were each confined to one of the evolutionary lineages, and 85 of the 86 strains which carried protein antigen c belonged to phylogenetic division II. Most of the type III organisms were assigned to two clone families. The characteristics of this French population argue for the existence of particular groups of strains responsible for neonatal meningitis and demonstrate that serotyping can supply information about the genetic distribution of strains.

Alleles↗
PubMed1995

Genetic diversity of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis revealed by restriction fragment length polymorphism of the rRNA gene region.

The restriction fragment length polymorphism patterns of rDNAs from Pseudomonas aeruginosa strains isolated from the respiratory tracts of patients suffering from cystic fibrosis were obtained to evaluate the genetic polymorphism of this population of strains. Eighty-seven P. aeruginosa strains isolated from 87 patients from diverse areas of France and the ATCC 10145 strain were examined. Four restriction enzymes were used: BamHI, ClaI, EcoRI, and PstI. Forty-nine strains (56%) were in the three most frequent ribotypes (ribotypes R1 to R3). In addition, hierarchical clustering analysis of the data showed that 71 of the 88 strains (81%) clustered at a distance of less than one-third of the greatest distance observed in the total population. This indicates that clinical isolates implicated in the pathology of cystic fibrosis present a low degree of heterogeneity of rRNA operons, in contrast to the heterogeneity of strains of P. aeruginosa isolated from patients with various other pathologies. This relative homogeneity of rRNA genes was observed independently of the clinical status of the patient and the colony morphology.

Adolescent↗
PubMed1995

Relapse of herpes simplex encephalitis.

We report five children who had recurrent central nervous system signs after conventional acyclovir therapy for herpes simplex encephalitis. Secondary exacerbation was characterized clinically by severe ballismic movement disorder in all five children, associated with fever, impairment of consciousness, and seizures. Biologic analysis in all children and magnetic resonance imaging and neuropathology studies of the brain in three cases were compatible with inflammatory reaction. In contrast, all viral cultures remained negative, herpes simplex virus antigen in one child and DNA tested by polymerase chain reaction in four children were undetectable in the first samples of cerebrospinal fluid during the relapse, suggesting a postinfectious, immune-mediated mechanism of relapse in these patients.

Acyclovir↗