HIV type 1 genetic diversity and genotypic drug susceptibility in the Republic of Moldova.

HIV-1 genetic diversity and, for the first time, genotypic drug susceptibility was investigated for strains circulating in the Republic of Moldova (of the former Soviet Union). Eighty-three samples from adults recently infected by intravenous drug use (IDU) (n = 60), heterosexual contact (n = 8), and from blood donors (n = 15) that tested positive from 1997 to 1998, and originating from different regions of Moldova were serotyped. By group-specific and subtype-specific peptide ELISA, patients were infected by serotype A (n = 65), serotype B (n = 1), or were nontypable (n = 17). Heteroduplex mobility assay (HMA) confirmed 11 subtype A and the one subtype B infection. Analyses of pol and env sequences for six of the IDUs confirmed that they were infected with subtype A strain. These strains clustered tightly with subtype A strains isolated from the former Soviet Union in phylogenetic analysis. No mutations associated with drug resistance were detected. The Republic of Moldova is culturally more closely related to Romania (where subtype F dominates the epidemic), but depends economically on Russia (where subtype A is established among IDUs). Thus, our results suggest that the spread of HIV in this region is driven by drug networks rather than being due to cultural similarities.

HIV-1 diversity in Romania.

OBJECTIVES: To evaluate the prevalence and the dynamics of HIV-1 subtypes in Romanian adults and children, and to investigate the origins of the nosocomial epidemic. DESIGN: A total of 1000 serum and plasma samples, from adults (n = 579) and children (n = 421) who were diagnosed as being HIV-1-infected during 1990-1997 in 39 of the 41 Romanian districts, were serotyped. Viral DNA was isolated from blood samples of 84 patients and the viruses were genotyped. METHODS: Serotyping was performed with a peptide subtype-specific enzyme immunoassay (SSEIA), based on in vitro competition for antibody binding between the representative V3 peptides of the different clades (A-F). Proviral HIV-1 DNA was genotyped by heteroduplex mobility assay or by sequence analysis of the C2-V3 env region. RESULTS: SSEIA showed that 93% of the samples from horizontally infected children were serotype F, 1% were serotype B, and the remaining 6% were uninterpretable. In vertically infected children, 74% of strains were serotype F, 10% were serotype A, 3% were serotype B, and 3% were serotype E. Serotype F was also the dominant subtype in adults (68%), but serotypes A, B, C, D and E were also detected. SSEIA gave indeterminate results in 7% of cases. A strong correlation (90%) between serotyping and genotyping for subtype F was found. Analysis of the relative incidence of the different serotypes over a 7-year period (1990-1997) showed a stable distribution. CONCLUSIONS: Subtype F largely dominates the epidemiology of HIV-1 infection in both children and adults in Romania, although other major subtypes are present. The predominance of subtype F in Romania may be a future potential source of HIV-1 variability in Europe.

[Demonstration of viral proteins by silver staining]. / Mise en évidence des protéines virales à l'aide de la coloration par l'argent.

Investigations were conducted to establish the optimal conditions for silver staining of polypeptides separated by polyacryle-amide gel electrophoresis. The thickness of the gel layer was of 1.5 mm. The experiments showed that the modified Hankeshover and Dernick's technique (4) (replacement of the fixative for the electrophoretically separated polypeptides and extension of the bleaching by Farmer's reagent time) had the best sensitivity and reproducibility. This technique can be performed also on polyacryle-amide gel preparations already stained by the Coomassie Brilliant Blue method. To check the efficiency of this silver staining technique, the authors used it to detect the Sendai virus and B hepatitis virus surface antigen polypeptides.

Characterization of an enzyme immunoassay by means of specific interaction affinities.

Antigen--antibody interactions involved in an enzyme immunoassay are characterized by their specific affinities. The use of a nonlinear least-squares approach of the response versus dose dependence allows the extrapolation of experimental data, as well as qualitative and/or quantitative assumptions about the interactions studied. As a practical test, the present technique has important advantages over common titration methods, by avoiding the fixation of a cut-off limit for positive and negative samples and by determining the affinity of the specific interaction for any dose required.

Possible structure/antigenicity relationships within the outer coat of hepatitis B virus (HBV).

A model image of the organization of the HBV coat is proposed on the ground of published evidence, as well as the authors' own results concerning the dissociation of the viral coat into lipoprotein subunits devoid of HBsAg activity. Structural relationships are envisaged and the existence of a hypothetical polypeptide structure possessing hydrophobic and/or polar binding sites is inferred.