Hepatitis a virus: Structure-functional features of genome, molecular diagnostics, and cultivation

Recently published data on the following features of hepatitis A virus (HAV) are reviewed: structure-functional genome features, genotyping, clinical findings, and current means of diagnostics. The growing need to study the genetic diversity of HAV isolates and the search for its possible new antigenic variants are underlined. Results of cultivation of different HAV strains are considered and analyzed for possible application in creation and production of vaccines and diagnostic kits.     

Development and verification of real-time PCR assay for identification of viral agents causing acute respiratory infections in human beings

A multiplex polymerase chain reaction (PCR) for identification of four viruses causing acute respiratory diseases in human beings was developed. The analytical sensitivity of developed RT-PCR for identification of adenovirus, respiratory-syncytial virus, flu viruses types A and B, and actual subtypes of type A flu virus (seasonal and pandemic variants H1N1, seasonal H3N2, and viruses of bird flu that are pathogenic to human beings H5 and H7) was 1 × 10³ genome equivalents per milliliter. Diagnostic sensitivity for flu virus type A and B, and also subtypes H1 (seasonal H1N1, pandemic variant of H1N1 of year 2009), H3, H5 was 1 × 10³–10⁴ viral particles per milliliter. The method developed has high specificity and does not have positive signal in experiments with DNA/cDNA of human beings and viral DNA. We have studied 50 samples using the developed set. Etiology was defined in 33 samples.     

The Opisthorchis felineus paramyosin: cDNA sequence and characterization of its recombinant fragment

The cDNA sequence of Opisthorchis felineus paramyosin (PM) was determined and shown to have 66-70% homology with two schistosomes and two cestodes. Phylogenetic analysis revealed an almost equal distance between O. felineus and these distinct clades. Because of its relatively low conservation, the PM gene may be a convenient genetic marker for studying phylogenetic relationships among platyhelminthes.A 25-kDa recombinant polypeptide corresponding to the central part of the full-length PM was produced. In Western blot analysis, murine hyperimmune serum against recombinant PM (recPM) detected 100-kDa polypeptides in the O. felineusegg and somatic antigens. Interactions of recPM with polyclonal anti-parasite antibodies and anti-recPM sera in ELISA with native antigens demonstrated that recPM carries a B cell epitope identical to the O. felineusnative antigen. Our sequence and immunologic data may be helpful in developing new diagnostic tools and candidate vaccines for O. felineus infection.     

Potential of Phosphorus Nuclear Magnetic Resonance Spectroscopy in Studies of the Energy Metabolism of Skeletal Muscles

The aim of the present study was to investigate the possibility of phosphorus magnetic resonance spectroscopy (MR spectroscopy) in the diagnosis of metabolic lesions of skeletal musculature in patients with intermittent claudication syndrome, chronic cardiac failure, and varicose diseases of the lower limbs. Studies included 50 males: 20 patients with intermittent claudication, 10 patients with chronic cardiac failure, and 10 patients with varicose veins. The control group consisted of 10 healthy volunteers. The following measures were determined: the phosphocreatinine index, the intracellular pH in the gastrocnemius muscle, and the half-recovery time for the phosphocreatinine index. The phosphocreatinine index and the pH at rest did not differ between study groups. Isotonic exercise produced no change in the phosphocreatinine index in the control group; patients with intermittent claudication showed a 26.1% decrease, patients with chronic cardiac failure showed an 8% decrease, and patients with varicose veins showed a 25.6% decrease. The only group showing a significant decrease in pH during exercise was the group of patients with intermittent claudication. This group also showed an inverse correlation between the pressure index and the extent of the decrease in the phosphocreatinine index. Thus, MR spectroscopy provides a non-invasive diagnostic method for lesions of energy metabolism in skeletal musculature in patients with deranged peripheral hemodynamics.     

Neutralizing monoclonal antibodies against Russian strain of the West Nile virus

We have developed a panel of 16 hybridomas secreting neutralizing monoclonal antibodies (Nt- MAbs) to Russian isolate (LEIV-Vlg99-27889-human) of the West Nile virus (WNV). Most of the Nt-Mabs were either IgG1 or IgG3 subtypes. Nine of the 16 neutralizing MAbs detected WNV protein E in Western blot. According to their Nt-activities, Western blot results and cross-reactivity, the MAbs were divided into four groups. Monoclonal antibodies from group I were able to neutralize WNV strains Vlg99-27889, Vlg00-27924, Hp-94, A-1640, A-72, Tur-2914, and Eg101. The Nt-activity of MAbs from groups II-IV towards these WNV strains was variable. Recombinant fragments E(1-180), E(1-321), and E(260-466) of protein E were used for preliminary mapping of domains recognized by Nt-MAbs. Only five Nt-MAbs were able to react with the recombinant polypeptides. The MAbs 9E2, 7G9, 11G3, and 7E6 from group Ia recognized Nt-epitope(s) between amino acids 321 and 466 of protein E and Nt-MAb 4F11 (group III) reacted with residues 1-180. This demonstrates that two discrete regions of protein E are involved in neutralization of WNV. Our data on immunochemical, biological activities of Nt-MAbs and mapping of Nt-epitopes using recombinant polypeptides suggest at least 13 different Nt-epitopes for WNV.