[Test for specific antibodies to virus hepatitis delta based on synthetic peptides]. / Opredelenie spetsificheskikh antitel k virusu gepatita del'ta na osnove sintetitseskikh peptidov.

Solid-phase synthesis of three linear peptides overlapping the major immunodominant epitope of HDAg, which located within amino acid (aa) segment 53-108, and peptide aa 167-179 was carried out. The structure of the peptides corresponded to the sequences of isolates HDV type I. Their antigen reactivity was studied by indirect enzyme immunoassay with sera from patients with hepatitis D and from asymptomatic carriers of anti-delta antibodies. Two B-epitopes located within aa 53-80 and 71-93 appeared to be the most immnunoreactive. The use of these peptides in ELISA allowed anti-delta IGg antibodies to be detected with 95% confidence in serum of patients with hepatitis D and with 87% confidence in serum of asymptomatic carriers of anti-delta antibodies. Analysis of obtained data showed that these peptides can be used in new diagnostic anti-HDV tests.

[Seroconversion to various hepatitis C virus antigens in patients with hepatitis C from various sources]. / Issledovanie serokonversii k razlichnym antigenam virusa gepatita C s razlichnymi iskhodami.

A total of 136 patients with acute icteric hepatitis C, including patients with known outcome, were examined. Therefore, 46 serological samples, obtained from 13 patients with subsequent remission, and 63 samples, obtained from 13 patients, who subsequently developed the chronic disease stage, were analyzed. The serum of known outcome patients were examined, by using the immune-enzyme analysis method, to the antibodies of both class IgG, and IgM. Differences in the dynamics of the immune humoral response were established with due regard for a pathological course process, including the acute disease stage. The obtained results are interesting because of their prognostic values.

[Determination of type-specific synthetic peptide antibodies to hepatitis delta virus ]. / Opredelenie tipospetsificheskikh antitel k virusu gepatita del'ta na osnove sinteticheskikh peptidov.

Nine peptides from immunodominant (53-68 and 65-80 aa) and hypervariable (201-213 aa) regions derived from delta antigen sequences corresponding to 3 HDV genotypes were synthesized. Type specificity of antibodies to the resultant peptides was evaluated by indirect enzyme immunoassay with sera from patients with hepatitis D and asymptomatic carriers of anti-delta antibodies. Analysis of the results showed that HDV circulating in the Central Volga region belongs to type I in the majority of cases. High heterogeneity and changeability of HDV genome during the period of transition from acute forms to asymptomatic carriership was revealed. Possibility of circulation of new hybrid HDV strains causing mixed infection in Russia is discussed.

[Serological study of hepatitis C virus NS5 protein epitopes and their clinical and diagnostic significance]. / Serologicheskoe issledovanie épitopov belka NS5 virusa gepatita C i ikh znachenie dlia kliniki i diagnostiki.

Three peptides corresponding to the 2295-2317 aa NS5 HCV region and individual parts of this region were synthesized. Antigenic properties of these peptides were investigated. The 2295-2317 aa region contains at least two epitopes of different nature. The full-sized peptide is more promising for the diagnostic studies. Optimal conditions for ELISA with this peptide were defined, allowing the maximum complete utilization of the potentialities of both epitopes.

[Detection of type specific antibodies to hepatitis C virus NS4 protein in hepatitis C patients by enzyme immunoassay]. / Vyiavlenie tipospetsificheskikh anti-HCNS4-antitel u bol'nykh gepatitom C metodom immunofermentnogo analiza.

A multi-enzyme immmune-assay test system was designed for serotyping of genotypes hepatitis C virus (HCV) and a method of such typing of the serum of patients with hepatitis C was worked out. The above test-system was worked out on the basis of a study of 10 type-specific peptides modeling different fragments from NS4-protein variable region of HCV. The designed test system was evaluated by using a set of 42 serum samples obtained at random from patients with chronic hepatitis C, which had been preliminarily genotyped by polymerase chain reaction. The serotyping makes it possible to identify the type-specific antibodies in the blood sera of patients, including those cases when viremia was absent. Differences in the circulation of HCV in Moscow (Russia) and Vitebsk (Byelorussia) were established by using the designed test-system.

[Spectrum of antibodies to HCV antigens in patients with different clinical patterns of chronic HCV infection]. / Spektr antitel k razlichnym antigenam HCV pri raznykh variantakh techeniia khronicheskoi HCV-infektsii.

Correlations between the spectra of antibodies to HCV proteins represented by various antigenic determinants and clinical variants of chronic HCV infection were studied. Synthetic peptides core-16, NS4-20, and NS5-23 simulating the immunodominant regions of the core, NS4 and NS5 proteins and recombinant proteins core-114 and NS4-86 were used as antigens. The results indicate that if the serum of an HCV patients contains no IgG to both antigenic determinants of NS4 or to NS5 in combination with any core antigenic determinant, a clinical and biochemical remission is highly probable. Chronic hepatitis C is characterized by the presence of IgG in high titers to both antigenic determinants of NS4 protein, particularly in combination with anti-NS5 IgG in low titers or none at all, or high titers of anti-core-16 IgG in combination with high titers of anti-NS4-20 IgG.

[Type-specific antibodies to hepatitis C virus in sera from patients with various hematologic diseases]. / Tipospetsificheskie antitela k virusu gepatita C v syvorotkakh bol'nykh s razlichnymi zabolevaniiami krovi.

The reactivity of 100 sera taken from patients with different blood diseases and donors with respect to synthesized peptides in the variable area of protein NS4 of hepatitis C virus was studied. The presence of type-specific antibodies in the blood sera of patients with hepatitis C was shown. Two antigenic determinant corresponding to 1683-1705 and 1711-1732 amino acid residues in the protein area under study were detected. In hematological patients undergoing frequent blood transfusions mixed infection with different types of hepatitis C virus was registered; these types could be reliably determined with the use of synthetic peptides. The serotype determined with the use of peptides corresponded to the type of the circulating virus.

[Diagnostic significance of antibody detection to various hepatitis C virus antigens in patients with acute and chronic HCV-infection]. / Diagnosticheskaia znachimost' opredeleniia antitel k razlichnym antigenam virusa gepatita C u patsientov s ostroi i khronicheskoi HCV-infektsiei.

AIM: To examine diagnostic value of antibodies to various HCV antigens in patients with acute and chronic HCV-infection. MATERIAL AND METHODS: Enzyme immunoassay has tested blood sera from 136 patients with icteric acute hepatitis C (AHC) and 45 patients with chronic HCV infection for IgG antibodies to antigens of proteins core, NS4, NS5, HCV. Synthetic peptides core-16, NS4-20, NS5-23 were used as antigens. RESULTS: Patients with icteric AHC had IgG antibodies to antigens of both structural protein core and non-structural proteins NS4, NS5 of HCV as early as the first 10 days of jaundice. Occurrence of anti-core and anti-NS4 increases with the disease duration. Incidence of anti-NS4 correlated with duration of previous intravenous drug addiction. In patients with AHC early in the icteric period anti-core, anti-NS4, anti-NS5 were present less frequently than in patients with chronic HCV infection having elevated levels of AlAT. Significant differences were found neither with the group with normal AlAt nor in the spectrum of the detected antibodies between patients with acute and chronic HCV infection. CONCLUSION: Despite different frequency of anti-core, anti-NS4, anti-NS5 detection in patients with icteric AHC and patients with chronic HCV-infection and high AlAT, their high incidence rate in this or that group and absence of differences by the spectrum of the studied antibodies do not allow the fact of their detection to be a diagnostic marker differentiating acute HCV-infection with chronic one.