Biomedical subjects

F Damond

Publications and source records attributed to F Damond.

28 records · Page 2Linked to original sources

PubMed1998

Line probe assay for detection of human immunodeficiency virus type 1 mutations conferring resistance to nucleoside inhibitors of reverse transcriptase: comparison with sequence analysis.

We compared the line probe assay (LiPA) to sequence analysis for the detection of mutations conferring resistance to nucleoside inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). Plasma samples from 40 patients who had received zidovudine, dideoxyinosine, and dideoxycytosine, alone or in combination, and who were enrolled in the ALTIS 2 clinical trial (lamivudine [3TC] plus stavudine) were tested at enrollment and at week 24. RT PCR products from plasma were used for LiPA, and DNA was used for sequence analysis. LiPA gave uninterpretable results for 8.5% of the analyzed codons corresponding to 63 samples, mainly for codons 41, 69, and 70. Several minor discrepancies between the two methods occurred, mainly due to the ability of LiPA to detect mixed populations while sequence analyses detect a single homogeneous population. LiPA is suitable for detecting mixed populations and easy to implement in clinical laboratories and might be useful for epidemiological surveys of primary HIV-1 resistance.

Anti-HIV Agents↗

PubMed1998

Human immunodeficiency virus type 1 subtype F reverse transcriptase sequence and drug susceptibility.

We sequenced and phylogenetically analyzed the reverse transcriptase (RT) regions of the pol genes of 14 human immunodeficiency virus type 1 (HIV-1) isolates from Romanian patients, which were classified as subtype F on the basis of env gene structure. The RT sequences showed that the strains clustered phylogenetically and were equidistant from other HIV-1 subtypes as shown by the neighbor-joining and maximum-likelihood methods, allowing us to define HIV-1 subtype F according to the pol classification. The subtype F RT sequences differed from reported group M RT sequences by 10.94% (for nucleotides) and 7.6% (for amino acids). Phenotypic analysis of subtype F susceptibility to three classes of antiretroviral compounds showed an increase in the 50% inhibitory concentration of the tetrahydroimidazo[4,5,1-jk] [1,4]-benzodiazepin-2-(1H)-one and -thione (TIBO) derivate R82913 for one strain which was naturally resistant to this compound. This first report of subtype F pol sequences confirms the perfect correlation between the phylogenetic positions determined by env and pol analyses and suggests that virus variability might influence the efficacy of antiretroviral treatments. This finding warrants a global evaluation of the phenotypic and genotypic susceptibility of HIV-1 subtypes to antiretroviral drugs.

Adult↗

PubMed1997

Synthetic peptide ELISAs for detection of and discrimination between group M and group O HIV type 1 infection.

We developed and evaluated two peptide-based immunoassays to confirm and discriminate between group M and group O HIV-1 infection. These assays are based on in vitro competition for antibody binding between M and O peptides. The first EIA is based on competition between group M and group O gp41 immunodominant domains and the second on competition between group O and group M V3 regions of gp120. Two panels of sera were used: the first consisted of 109 sera collected from 27 group O- and 92 group M-infected patients in whom the HIV isolates had been genotyped by sequencing or heteroduplex mobility assay. In this panel, the combination of the two assays correctly discriminated 106 samples (100% group O and 96.7% group M samples). The second panel, used for the field evaluation of the two assays, consisted of 157 samples from HIV-1-infected Cameroonian patients, 33 strains having been genotyped. The combination of the two techniques in a serogrouping algorithm discriminated 147 of these samples, 74 being HIV-1 group O and 73 group M. These results always correlated with genotyping results. The 10 sera that were not successfully classified by these assays were from early seroconverters. Altogether, the two assays clearly differentiated 263 of 276 (94.9%) samples in the two panels. On the basis of the genotyping results, the positive predictive value for group discrimination in the two panels was 100% for both GSEIA assays. Our peptide-blocking group-specific EIAs for differentiation and confirmation of HIV-1 group M and group O infection are complementary tools for epidemiological studies and surveillance of HIV-1 group O strain trafficking.

Amino Acid Sequence↗

PubMed1997

Serological and virological characterization of HIV-1 group O infection in Cameroon.

OBJECTIVES: To study the presence of HIV-1 group O infection among HIV-infected people in Cameroon and to further characterize the HIV-1 group O infections. DESIGN AND METHODS: During a 2-year survey (1994-1995), all samples tested positive in screening methods in the National Reference and Public Health Laboratory, Centre Pasteur, Yaoundé, Cameroon were identified as HIV-1 group M, HIV-1 group O or HIV-2 by using a serological algorithm. HIV-1 group M and HIV-1 group O were distinguished on the basis of competitive enzyme-linked immunosorbent assay (ELISA) reactivity against gp41 group M recombinant protein. HIV-1 group O infections were confirmed by using group O-specific V3 synthetic peptides. HIV-1 group O strains were isolated by lymphocyte cocultures, proviral DNA was amplified with specific primers, and sequencing was performed on the C2V3 and gag regions. RESULTS: Of the 8,331 screened samples, 3,193 were HIV-reactive, 2,376 (74%) of which were considered to belong to group M. The 817 (26%) that had reacted poorly or not at all against group M gp41 were further characterized: 10 were confirmed as HIV-2 and 82 as HIV-1 group O, the others being indeterminate (n = 285) or negative (n = 440). The frequency of group O relative to group M ranged from 1% in Far North province to 6.3% in the capital. There was no difference in sex, age or frequency of clinical manifestations between group M and group O infections. Group O infection was confirmed in a subset of cases by polymerase chain reaction (n = 14), with perfect concordance. Sequencing and phylogenetic analyses confirmed the high variability inside group O. CONCLUSIONS: Group O and group M epidemiological patterns are known to be similar so the reason for the lower prevalence of group O remains to be found. The wide distribution of group O infection in all Cameroonian provinces underlines the importance of further characterizing the epidemic spread and diffusion of this group.

Amino Acid Sequence↗

PubMed1997

Diversity of the immunodominant epitope of gp41 of HIV-1 subtype O and its validity for antibody detection.

The immunodominant regions of the gp41 from 13 HIV-1 subtype O strains from Cameroon, 11 from France and one from Germany were sequenced. The amino acid sequences were compared to those of the 3 published HIV-1 subtype O isolates, ANT70, MVP-5180 and VAU. All HIV-1 subtype O isolates had a very conserved amino acid sequence in this region and showed a subtype O specific structure. Within the cysteine loop there was a positive charge of two basic amino acids, arginine and lysine. Only two strains (CM.6778 and CM.8161) showed an acidic amino acid in this loop. None of the isolates showed the same amino acid sequence in this immunodominant region. A 25 residue peptide from the immunodominant domain of gp41 of the MVP-5180 strain was synthesized, cycled to form the cysteine-loop and coated to microtiter plates. Antibody binding was detected by indirect ELISA using an enzyme labeled anti-human IgG. Out of 111 anti-HIV-1 positive specimens, collected mainly from Cameroonian HIV infected patients, only 10 were not reactive in this assay. The 42 anti-HIV-1 subtype O positive specimens gave all a reaction above cut off. Despite the diversity found in the amino acid sequences within the 25 isolates a peptide-based indirect ELISA representing the immunodominant epitope of the strain MVP-5180 successfully detected all the anti-HIV-O sera so far tested, pointing to the importance of adding such a peptide for correct identification of HIV-1 subtype O infected patients, while some assays without HIV-O specific antigens partially fail to detect all anti-HIV-O specimens.

Amino Acid Sequence↗

PubMed1997

Susceptibility of human immunodeficiency virus type 1 group O isolates to antiretroviral agents: in vitro phenotypic and genotypic analyses.

We investigated the phenotypic and genotypic susceptibility of 11 human immunodeficiency virus type 1 (HIV-1) group O strains to nucleoside and nonnucleoside reverse transcriptase (RT) inhibitors and protease inhibitors in vitro. Phenotypic susceptibility was determined by using a standardized in vitro assay of RT inhibition, taking into account the replication kinetics of each strain. HIV-1 group M and HIV-2 isolates were used as references. DNA from cocultured peripheral blood mononuclear cells was amplified by using pol-specific group O primers and cloned for sequencing. Group O isolates were highly sensitive to nucleoside inhibitors, but six isolates were naturally highly resistant to all of the nonnucleoside RT inhibitors tested. Phylogenetic analysis of the pol gene showed that these isolates formed a separate cluster within group O, and genotypic analysis revealed a tyrosine-to-cysteine substitution at residue 181. Differences in susceptibility to saquinavir and ritonavir (RTV) were not significant between group O and group M isolates, although the 50% inhibitory concentration of RTV for group O isolates was higher than that for the HIV-1 subtype B strains. The study of HIV-1 group O susceptibility to antiretroviral drugs revealed that the viruses tested had specific phenotypic characteristics contrasting with the group M phenotypic expression.

Amino Acid Sequence↗

PubMed1996

HIV type 1 diversity in northern Paris, France.

During a 6-month period, we studied the diversity of HIV-1 subtypes in 392 adult patients seen in Bichat-Claude Bernard Hospital, northern Paris, France. All the samples were serotyped and a subset was genotyped by means of HMA. Serotyping was performed with a new peptide subtype-specific EIA (SSEIA), based on in vitro competition for antibody binding between the representative V3 peptides of the different clades (A to E). HMA with plasmids from clades A to H gave unambiguous results on 105 of the 116 samples tested. The agreement between SSEIA and HMA was 36/41 for subtype B, 2/2 for subtype D, and 4/5 for subtype E. We found a discrepancy in the results between clade A and C: the patients with sera reacting to peptide C were confirmed by HMA as being infected by clade A strains. Three patients reactive with peptide A were infected by a subtype F. These results indicate that peptide cross-reactivity, even in the SSEIA format, hinders serotyping. In 11 samples, all from African patients, the subtype remained indeterminate because PCR or HMA failed. Caucasian patients (n = 223) were mainly infected by subtype B. HMA and/or SSEIA revealed non-subtype B infection in 14 Caucasians, who were infected by the sexual route overseas or in France. Patients originating from other countries (mainly in Africa) exhibited a broad strain diversity, with most of the different subtypes so far described being represented. This study confirms the frequency of subtype B strains in Caucasians living in France, but emphasizes the emergence of the different HIV-1 subtypes in Paris, together with the extent of strain trafficking. Discordances between serotype and genotype assays confirm that both tests require additional development.

Adult↗

PubMed1996

Lack of screening test sensitivity during HIV-1 non-subtype B seroconversions.

OBJECTIVE: To evaluate the serological consequences of HIV-1 group M diversity we studied the ability of screening tests to detect anti-HIV antibodies in early seroconverters infected by different HIV subtypes. SETTING: Virology Department, Bichat-Claude Bernard Hospital, Paris, France. DESIGN AND METHODS: Symptomatic patients with serial samples and with infective strains characterized by heteroduplex mobility assay. In each case, two sera were selected. The first (pre-seroconversion sample) was the last p24 antigen-positive/Western blot-non-reactive sample. The second (seroconversion sample) was the first Western blot-reactive sample. One second-generation enzyme immunoassay (EIA; Abbott) based on anti-human immunoglobulin (Ig) G-conjugate and three third generation EIA (Abbott; Enzygnost; Genscreen) based on the double antigen sandwich principle, detecting IgM and IgG, were used. RESULTS: Ten patients had subtype B strains and nine had non-B strains (seven were A, one E and one G). The Abbott third-generation test was more sensitive than the second generation test for pre-seroconversion subtype B samples (nine versus four out of 10; P < 0.05), but not for non-B subtypes; only two of the nine non-B sera tested were positive by both EIA. Positivity rates and optical densities differed (P < 0.05) between B and non-B subtypes in all third-generation EIA. There was no significant difference between the subtype B and non-B groups with regard to the interval between the pre-seroconversion sample and the seroconversion sample (subtype B, 6.7 +/- 2.6 days; non-B, 5.2 +/- 1.7 days). No significant difference in positivity rates and optical densities were found between B and non-B subtypes in these seroconversion samples. CONCLUSION: The shorter time since HIV infection required for sera to become reactive in third-generation EIA screening tests is due to better sensitivity for subtype B strains only. These results stress the importance of strict donor selection, the need to test screening kits against large panels of all subtypes, and the place of p24 antigen testing in closing the window of seroconversion.

Antibodies, Viral↗

PubMed1996

Response to fluconazole by 23 patients with human immunodeficiency virus infection and oral candidiasis: pharmacological and mycological factors.

The MICs of fluconazole for strains of Candida species and the levels of fluconazole in serum were determined at day 0 and day 14 for 23 human immunodeficiency virus-infected patients with oral candidiasis who were treated orally with 100 mg of fluconazole per day for 14 days. Among the 23 patients, 11 (48%) were not clinically cured and had persistent isolation of Candidiasis albicans (n = 10) and/or presence of non-C. albicans (n = 6). Clinical response could be predicted by the susceptibility of the strain to fluconazole determined at day 0. All 12 patients who were cured were infected with a strain for which the MIC was < 0.78 mg/liter. All four patients who were infected with a strain for which the MIC was > 3.12 mg/liter experienced clinical failure. These data suggest that a C. albicans strain could be defined as being susceptible when the MIC of fluconazole is < 0.78 mg/liter and as being resistant when the MIC is > 3.12 mg/liter.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

[Variability of human immunodeficiency virus type 1].

The variability of human immunodeficiency virus type 1 (HIV-1) is very high. To date, three distinct lineages of HIVs, type 1 group M, type 1 group O and type 2 are described, suggesting at least three different zoonotic infections. HIV-1 group M is responsible for the global epidemic of AIDS. At least ten subtypes of HIV-1 group M, labelled A through J, have been discovered. Viral sequences from both the gag and the env gene, particularly a part of gp 120 referred to as the V3 region have been used to identify subtypes of HIV-1 group M. The nucleotide distance between viruses of different subtypes is on average 30% for the env gene. The various subtypes are geographically distributed throughout the world. Some of the subtypes were identified as recombinant or mosaic viruses. The existence of different subtypes of HIV-1 have major implication for vaccination. They may also influence the diagnosis of HIV infection. To date, it is unclear whether subtypes of HIV-1 differ with respect to transmissibility or pathogenicity.

Acquired Immunodeficiency Syndrome↗