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F Barin

Publications and source records attributed to F Barin.

At least 19 recordsLinked to original sources
PubMed2000

Identification of the glycoprotein 41(TM) cytoplasmic tail domains of human immunodeficiency virus type 1 that interact with Pr55Gag particles.

We investigated the protein/protein interactions that occur during human immunodeficiency virus (HIV-1) budding. We evaluated the binding to Pr55Gag particles of peptides mapping to the cytoplasmic tail of gp41TM and of host-cell proteins, in a cell-free, in vitro assay. Host-cell proteins and irrelevant viral envelope peptides did not bind. Peptides corresponding to a large central domain of the gp41TM cytoplasmic tail (93 residues) bound to Pr55Gag particles. This demonstrates that a Gag/Env interaction is responsible for the specific incorporation of the Env glycoprotein into nascent HIV-1 virions, and defines more accurately the gp41TM domain involved in this interaction.

Amino Acid Sequence↗
PubMed2000

Antigenic properties of recombinant envelope glycoproteins derived from T-cell-line-adapted isolates or primary human immunodeficiency virus isolates and their relationship to immunogenicity.

The native envelope glycoproteins of primary HIV-1 virions have weaker antigenicity than do T-cell laboratory-adapted (TCLA) viruses. These antigenic properties require further evaluation if recombinant envelope glycoproteins are produced as part of a vaccine strategy. In this study, we compared the antigenicity of recombinant envelope glycoproteins derived from three primary isolates (PI) (HIV-1(BX08), HIV-1(CHA), and HIV-1(133)) and two TCLA viruses (HIV-1(HXB2) and HIV-1(MN)) produced using the Semliki Forest virus (SFV) system. This analysis was performed by radioimmunoprecipitation assays and flow cytometry. The results suggest that the SFV produces envelope glycoproteins with features in common with the envelopes found in naturally occurring virions. In particular, the PI envelopes had weak heterogeneous antigenic properties. However, the cytometric analysis also showed that there was less envelope glycoprotein on the cell surface for the PI envelopes than for those of TCLA viruses, suggesting differences in their intracellular trafficking. The immunogenic properties of the various envelope glycoproteins were evaluated in mice using recombinant SFV particles as vaccine vectors. The PI envelopes were less immunogenic than the TCLA envelopes, probably due to both their low antigenicity and cell surface expression level. Thus, it may be difficult to design an effective vaccine based on native recombinant PI envelopes.

Adaptation, Physiological↗
PubMed2000

HIV-1 diversity in France, 1996-1998. The AC 11 laboratory network.

OBJECTIVE: To study the distribution of HIV-1 subtypes in France and to describe the characteristics of patients infected with non-B subtypes. METHODS: All adults who tested HIV-1 positive on Western blot for the first time in one of the participating laboratories between September 1996 and March 1998 were eligible, whether or not they had been diagnosed previously elsewhere. Data on age, sex, country of birth, HIV-transmission group, dates of the last negative and first positive HIV test and clinical stage were collected. Serotyping was performed with a peptide subtype-specific enzyme immunoassay on each plasma sample and genotyping with heteroduplex mobility assay on each non-B serotype-infected patient. Patients characteristics were compared in B and non-B subtypes. RESULTS: Of the 2168 HIV-positive patients included by 32 laboratories, subtype,results were available for 2042. Among those, 73.4% were men, 12.2% born in sub-Saharan Africa, 41.5% infected through heterosexual contact and 67.6% in CDC stage A. Among the 2042 patients, 1 725 (84.5%) were infected with B subtype. Among the 317 non-B subtypes, subtype A was predominant (66.9%); all other subtypes (C, D, E, F, G, H, O) were present. Factors independently associated with a non-B subtype were to be included in the Paris area [adjusted odds ratio (aOR), 1.6; 95% confidence interval (CI), 1.1-2.3], to be born in sub-Saharan Africa (aOR, 26.0; 95% CI, 17.5-37.8) and to be infected through heterosexual contact (aOR, 4.2; 95% CI, 2.8-6.4). CONCLUSIONS: In France, although B subtype is still predominant, all non-B subtypes are now present. The diversity of HIV strains may affect diagnostic tests and clinical practice, especially viral load measurements. Moreover, the decreased susceptibility of non-B subtypes to antiretroviral drugs emphasizes the importance of surveillance of HIV diversity.

Adult↗
PubMed2000

[Viruses and unconventional transmissible agents: update on transmission via blood ].

The blood borne viruses must be separated into major and minor agents. Major viruses transmissible by blood transfusion are human immunodeficiency virus (HIV) and hepatitis B and C viruses (respectively HBV, HCV). The prevalence of virological markers in French blood donors has been continuously decreasing since the implementation of serological screening methods as soon as they were available. In 1998, the prevalences (per 10,000 donations) were 0.17 for antibody to HIV, 0.08 for antibody to human T-cell leukemia virus (HTLV), 2.23 for hepatitis B surface antigen (HBs Ag) and 2.52 for antibody to HCV. The values are, of course, higher in new donors when compared to regular donors: approximately five-fold for HIV, 50-fold for HCV and 300-fold for HBs Ag. The remaining major questions concern the residual risk due to infectious donations which could escape the preventive measures. It seems evident that the major risk is imputable mainly to donations collected during the window period. During the 1996-1998 period, the residual risk for HIV was 1 out of 1,350,000 donations, 0 for HTLV, 1 out of 375,000 for HCV, and 1 out of 220,000 for HBV. A few cases of "immunosilent" patients have been reported. They remain exceptional. The first data collected after the implementation of nucleic acid technology (NAT) confirm the very low residual risk. The recent introduction of leukodepletion probably brought an important contribution to diminishing the risk of transmission of leucotropic viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesviruses-6, -7 and -8, and HTLV. If the purification process of plasma-derived medicinal products including inactivation procedures makes it possible to be confident with the elimination of infectivity due to enveloped viruses, the detection of nucleic acid sequences derived from naked viruses in plasma pools such as parvovirus B19 or hepatitis A virus (HAV), and/or the introduction of a nanofiltration step during the purification process, when possible, may greatly contribute to their safety. The emergence of a new form of the Creutzfeldt-Jakob disease (nvCJD) introduces a new series of questions about the safety of blood products that, although the risks appear limited, are not yet resolved.

Biological Products↗
PubMed2000

[Genetic diversity of viruses. Consequences for screening and prevention].

The evolution of viruses contributes to their diversification, whether it be a result of their own replication, or host-pressure dependent. Certain viral types, groups or subtypes are therefore found in certain regions of the world or in certain populations. The development of blood screening reagents is nearly always based on viral antigens or viral sequences derived from 'prototype' strains or antibodies raised against these prototype strains. Therefore in situations where an individual is infected by a viral strain that is genetically and antigenically distantly related to the prototype strain used in the development of the test, screening failure may occur. In the present article, this has been illustrated via 3 models, the human immunodeficiency virus (HIV), the hepatitis B virus (HBV), and the B19 parvovirus. Viral diversity also has a negative effect on the prevention of blood-transmitted viral infections. The example provided concerns vaccination failure and/or seroprophylaxis against hepatitis B.

AIDS Serodiagnosis↗
PubMed2000

[Controlled viral risks].

The prevalence of virological markers in blood donors has been continuously decreasing since the implementation, as soon as they were available, of serological screening methods. In 1998, the prevalences (per 10,000 donations) were 0.17 for antibody to HIV, 0.08 for antibody to HTLV, 2.23 for HBs Ag and 2.52 for antibody to HCV. The values are of course higher in new donors when compared to regular donors: approximately five-fold for HIV, 50-fold for HCV and 300-fold for HBs Ag. The remaining major questions concern the residual risk due to infectious donations which could escape the preventive measures. It seems evident that the major risk is imputable mainly to donations collected during the window period. During the 1996-1998 period, the residual risk for HIV was one out of 1,350,000 donations, 0 for HTLV, one out of 375,000 for HCV, and one out of 220,000 for HBV. A few cases of 'immuno-silent' patients have been reported. They remain exceptional. The first data collected after implementation of Nucleic Acid Technology (NAT) confirm the very low residual risk. The molecular epidemiology of the concerned viruses applied to the evaluation of screening assays highlighted the impact of the genetic diversity on the efficiency of these assays. This is particularly evident for HIV and HBV. The recent introduction of leucodepletion probably brought an important contribution in diminishing the risk of transmission of leucotropic viruses such as cytomegalovirus, Epstein-Barr viruses, human herpesviruses 6 and 7, and HTLV. If the purification process of plasma derived medicinal products including inactivation procedures permits confidence in the elimination of infectivity due to enveloped viruses, the detection of nucleic acid sequences derived from naked viruses in plasma pools may greatly contribute to their safety.

Antibodies, Viral↗
PubMed2000

[The virus isolated from patient TT (TTV): still an orphan 2 years after its discovery].

TTV is the acronym for a virus isolated two years ago from a patient whose initials were T.T. It is a naked virus probably belonging to the Circoviridae family. TTV has a particle size of 30-50 nm and possesses a single-strand circular DNA. Epidemiologic data are derived from studies looking for the viral DNA by the polymerase chain reaction (PCR). Important differences between early and recent studies appear to be due to the use of PCR assays based on primers located in different regions of the genome. Based on the most recent studies, the prevalence of TTV infections seems very high in the general population. TTV is present in the feces and would be transmitted through the fecal-oral route. It appears to be a ubiquitous virus, also present in various animal species, from chickens to chimpanzees. No association to any pathology has been identified so far, and TTV infection does not have a significant effect on liver disease.

Blood Donors↗
PubMed2000

HCV RNA in blood donors with isolated reactivities by third-generation RIBA.

BACKGROUND: The objective of this collaborative study was to learn the proportion of HCV RNA-positive samples obtained from a population of donors with isolated anti-HCV reactivities by third-generation RIBA (RIBA-3) (indeterminate results). STUDY DESIGN AND METHODS: During a 2-year period, 11 blood transfusion centers kept all samples with indeterminate RIBA-3 results to test them by PCR, using both local and commercial techniques. RESULTS: Of the 758 RIBA-3 indeterminate samples, 10 (1.3%) were positive for HCV RNA: 3. 3 percent (6/180) and 1.3 percent (4/317) of samples with anti-core or anti-NS3 reactivity, respectively, and none of the 52 and 209 samples with anti-NS4 or anti-NS5 reactivity, respectively. HCV RNA-positive donors with anti-core reactivity were infected with different subtypes (1 with HCV subtype 1b, 1 with 2, 1 with 2a/2c, 2 with 3a, and 1 with 5a), and a follow-up indicated a chronic-carrier state in two of the six donors. Acute hepatitis was diagnosed in three of the four donors with anti-NS3 reactivity alone. Two of these three were IV drug users and were infected with subtype 1a. CONCLUSION: HCV RNA-positive donors with indeterminate results in RIBA-3 are extremely rare, but they do exist. They were observed only when either anti-core or anti-NS3 was present. With such a RIBA-3 profile, PCR testing remains necessary to reveal an eventual acute or chronic HCV infection.

Adolescent↗
PubMed1999

Serologic and genetic characterization of HIV type 1 subtypes on Reunion Island.

The aim of this study was to determine the HIV subtypes present on Reunion Island, a French island located in the Indian Ocean, where the first case of AIDS was diagnosed in 1987. Paired sera and blood samples were collected between September 1996 and September 1997 from 53 HIV-1-positive patients. Subtyping was performed by serotyping with a previously described subtype-specific enzyme immunoassay (SSEIA) and by genotyping with the heteroduplex mobility assay (HMA). When samples gave uninterpretable results with either of the methods, or discordant results, the V3 env region was sequenced and genetic subtypes were determined by phylogenetic analysis. Genetic subtyping showed that 48 of 53 patients were infected with HIV-1 subtype B (90.5%). This high prevalence of subtype B on Reunion Island is probably due to the regular exchanges with metropolitan France. The other five patients were infected with subtype A (9.5%); they had been directly linked to African populations. Of the 48 subtype B samples, 44 (91.7%) were correctly subtyped by SSEIA and 43 (89.6%) by HMA. However, the SSEIA did not allow the subtyping of A strains in three of five patients. Thus, the SSEIA could be an alternative routine technique for screening subtype B versus nonsubtype B HIV-1 strains.

Amino Acid Sequence↗
PubMed1999

V3 serotyping of HIV-1 infection: correlation with genotyping and limitations.

HIV-1 V3 serotyping is a classification of immunodeficiency viruses based on antibody binding to V3 peptides that allows obtaining information on circulating subtypes that could be important for population-based epidemiologic studies. Recently, several laboratories have developed V3 enzyme-immunoassays (EIAs) using V3 peptides of subtypes A to E. In the present study, the utility of including additional peptides of subtypes F to H to the EIA was evaluated on a panel of 203 well-characterized serum samples from patients with diverse geographic origins (22 countries) and known HIV-1 genotype (79 A, 61 B, 21 C, 7 D, 7 E, 21 F, 6 G, 1 H). The results indicate a high predictive value (ppv) for serotypes B (> or =0.86), D (1) and E (0.88), and confirm the difficulty of predicting genotype A or C based on serotype A or C. Results also indicate that inclusion of the F peptide in the V3 EIAs may be useful (ppv = 0.61), but introduction of peptides G and H failed to demonstrate significant sensitivity or specificity for these subtypes. Correlation between serotyping and amino-acid sequences of the V3 region from 103 samples allowed the identification of key amino-acids that appear essential for subtype-specific seroreactivity.

Amino Acid Sequence↗
PubMed1999

Human immunodeficiency virus type 1 subtypes differ in disease progression.

At least 10 different genetic human immunodeficiency virus type 1 (HIV-1) subtypes (A-J) are responsible for the AIDS pandemic. Much of the understanding of HIV-1 disease progression derives from studies in the developed world where HIV infection is almost exclusively subtype B. This has led many to question whether the properties and consequences of HIV-1 infection can be generalized across subtypes that afflict the majority of infected persons in the developing world. From 1985 to 1997, a prospective study of registered female sex workers in Senegal tracked the introduction and spread of HIV-1 subtypes A, C, D, and G. In clinical follow-up, the AIDS-free survival curves differed by HIV-1 subtype. Women infected with a non-A subtype were 8 times more likely to develop AIDS than were those infected with subtype A (hazard ratio=8.23; P=. 009), the predominant subtype in the study. These data suggest that HIV-1 subtypes may differ in rates of progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Serological diagnosis of human immuno-deficiency virus in Burkina Faso: reliable, practical strategies using less expensive commercial test kits.

Reported are the results of a cross-sectional survey in Burkina Faso to identify reliable, practical strategies for the serological diagnosis of HIV-1 and/or HIV-2 infections, using less-expensive commercial test kits in various combinations, as an alternative to the conventional Western blot (WB) test, which costs US$ 60. Serum samples, collected from blood donors, patients with acquired immunodeficiency syndrome (AIDS) and pregnant women, were tested between December 1995 and January 1997. Twelve commercial test kits were available: five Mixt enzyme-linked immunosorbent assays (ELISA), three Mixt rapid tests, and four additional tests including monospecific HIV-1 and HIV-2 ELISA. The reference strategy utilized a combination of one ELISA or one rapid test with WB, and was conducted following WHO criteria. A total of 768 serum samples were tested; 35 were indeterminate and excluded from the analysis. Seroprevalence of HIV in the remaining 733 sera was found to be 37.5% (95% confidence interval: 34.0-41.1). All the ELISA tests showed 100% sensitivity, but their specificities ranged from 81.4% to 100%. GLA (Genelavia Mixt) had the highest positive delta value, while ICE HIV-1.0.2 (ICE) produced the most distinct negative results. Among the rapid tests, COM (CombAIDS-RS) achieved 100% sensitivity and SPO (HIV Spot) 100% specificity. Various combinations of commercial tests, according to recommended WHO strategies I, II, III, gave excellent results when ICE was included in the sequence. The best combination of tests for strategy II, which achieved 100% sensitivity and specificity, was to use ICE and COM, the cost of which was US$ 2.10, compared with US$ 55.60 for the corresponding conventional strategy. For strategy III, the best combination, which achieved 100% sensitivity and specificity, was to use ICE, ZYG (Enzygnost Anti HIV-1/HIV-2 Plus) and COM, the cost of which was US$ 2.90 (19.2 times lower than the corresponding strategy requiring WB). No rapid test combination showed 100% sensitivity and specificity. Our results indicate that the serodiagnosis of HIV in Burkina Faso is possible by using reliable, less-expensive strategies which do not require Western blot testing. Moreover, there is a choice of strategies for laboratories working with or without an ELISA chain.

AIDS Serodiagnosis↗
PubMed1998

Comparative analysis of humoral immune responses to HIV type 1 envelope glycoproteins in mice immunized with a DNA vaccine, recombinant Semliki Forest virus RNA, or recombinant Semliki Forest virus particles.

The Semliki Forest virus (SFV) system seems to be a useful new approach for generating effective immune responses against HIV-1 in animal models. We evaluated this system by comparing the humoral immune responses raised in mice immunized against the HIV-1 envelope with the SFV system, a DNA vaccine, and a recombinant Env glycoprotein. gp160 ELISA antibody titers (204,800) were highest in the sera from mice immunized with recombinant Semliki Forest virus particles. These sera contained antibodies to the CD4-binding site and recognized linear epitopes on gp120 and gp41 that were also recognized by a pool of sera from HIV1-infected individuals. This demonstrates that the HIV-1 envelope produced in vivo by the SFV system does not fold aberrantly. A low level of neutralizing antibodies against the HIV-1LAI strain was also detected in the serum of one mouse immunized with recombinant SFV particles, suggesting that booster injections should be given to achieve a more effective immune response. SFV recombinant particles induced the strongest humoral responses to the HIV-1 envelope of all the potential HIV env vaccines tested.

AIDS Vaccines↗