[Evaluation of the commercial ELISA test-systems of different formats to detect specific IgM and IgG in the measles patients sera].

Nine commercial kits of "captured" and "indirect" format ELISA assay for the detection of specific IgM and IgG in sera of patients with measles were compared to each other. 72 sera specimens from typical medium-severity cases from a measles outbreak (2010) were collected on the 5-6th day after the rash onset. IgM was detected with "capture" tests (Vecto-Measles IgM, Vector Best, Measles IgM capture EIA, Microimmune Ltd) close to 100% of cases, irrespectively to the age and the initial vaccination status of the patients. The IgM result was negative in 23.6% by average while investigating using "indirect" format tests (Enzygnost Anti-Measles Virusll/IgM, Siemens; Anti-Measles Viruses ELISA (IgM), Eurominimum, Virion-Serion IgM (GmbH). These cases were in adults, the majority of which had 1-2 vaccinations in the past. The analysis of the presented data shows high correlation connection between the tests used and high confidence level for OD IgM and IgG of the sera of the patients with the primary and secondary immune response.

[Seroepidemiology of hepatitis A in Saint-Petersburg in 2009].

AIM: To determine immune structure of different population groups in Saint-Petersburg to hepatitis A virus in 2009 in order to study trends of epidemic process dynamics and planning of prophylactic measures. MATERIALS AND METHODS: Nine hundred and three citizens of Saint-Petersburg aged 3 months to 60 years were tested for anti-HAV by ELISA in 2009. Results were compared with data of previous study conducted in Saint-Petersburg in 1999. Two hundred injection drug users (IDUs) aged 14 - 29 years were tested additionally. RESULTS: In total in 2009, anti-HAV were detected in 32.5 +/- 1.6% citizens of Saint-Petersburg that is 2-fold lower than in 1999 (60.2 +/- 1.5%). Especially sharp decrease of anti-HAV prevalence in 2009 compared to 1999 was observed in age groups 15 - 19 years (by 2.6-fold), 20 - 29 years (by 3.1-fold), and 30 - 39 years (2.8-fold). Anti-HAV were detected in 58.5 +/- 3.5% of tested IDUs that 2.8-fold higher of that value observed in persons 14 - 29 years old from population sample (21.7 +/- 2.4%). CONCLUSION: Decrease of immunity to HA in population of Saint-Petersburg is very unfavorable prognostic factor pointing to strong possibility of HA outbreaks onset during worsening of epidemic situation. In such circumstances, active immunization against HA of wide strata of population should become important prophylactic measure.

[Molecular-epidemiologic characteristic of hepatitis A outbreak among workers of food stores network].

Investigation of hepatitis A (HA) outbreak developed in 2005 among workers of food stores networkwas performed using conventional epidemiologic diagnostics as well as methods of molecular epidemiology. In 14 of 15 ill persons, using polymerase chain reaction, HAV RNA was detected by PCR in serum obtained on 2 - 25 day of illness (mean - 9.3 days). In 10 cases it was possible to determine nucleotide sequence of VP1/VP2 region of HAV genome and perform phylogenetic analysis of obtained isolates. It was determined that all isolates belonged to subgenotype IA, had high degree of homology and grouped in one cluster. These findings demonstrate their descendance from one source of infection, which, with high degree of probability, was the cook who made salads from fresh vegetables. HAV strain, which caused this epidemic outbreak circulates in Saint Petersburg for a long time and was already detected in 2004. Importance of vaccination against HA for persons working in manufacturing and distribution of food and use of molecular epidemiologic methods of surveillance for this infection is underlined.

[The prospects for using the genetically engineered surface antigen of the hepatitis B virus (HBsAg) expressed by recombinant poxvirus strains as the basis for vaccines against hepatitis B]. / Perspektivy ispol'zovaniia genno-inzhenernogo poverkhnostnogo antigena virusa gepatitia B (HBsAg), ekspressiruemogo rekombinantnymi shtammami poksvirusov, v kachestve osnovy vaktsin protiv gepatita B.

The use of a recombinant poxvirus (RPV) strain, expressing HBsAg in the process of reproduction in different bioreactor systems under stationary and bioreactor conditions of cultivation, made it possible to obtain highly purified HBsAg. The identity and purity of HBsAg was confirmed by the analysis of its amino acid composition, SDS electrophoresis in polyacrylamide gel, electron microscopy and high-performance liquid chromatography. Good prospects of the use of RPV-expressed gene engineering HBsAg as the basis vaccines against hepatitis B was demonstrated in 10 experimental batches of vaccine. All batches of the preparation had pronounced immunogenicity and were safe and nontoxic in animal experiments. The ID50 of experimental batches did not exceed 211 ng/ml, which, according to the data of comparative experiments, was lower than, or equal to, corresponding values of analogous foreign commercial preparations, based on plasma or yeast HBsAg.

Principles of selective inactivation of viral genome. VII. Some peculiarities in determination of viral suspension infectivity during inactivation by chemical agents.

When the infectivity of the influenza virus is determined by means of titration on chicken embryos, calculating the infection titre according to Reed and Muench, the course of inactivation with beta-propiolactone shows an anomaly - the fraction of infected embryos in a batch initially increases and then decreases as the degree of dilution of the virus-containing sample is increased. This anomaly occurs because a slight dilution lowers the agent concentration insufficiently so that inactivation goes on after the dilution of the sample before and/or after the inoculation of the solution into the embryo. The anomaly can be avoided either by neutralizing or removing the agent prior to titration or by starting titration from high dilutions.

Principles of selective inactivation of viral genome. VI. Inactivation of the infectivity of the influenza virus by the action of beta-propiolactone.

The kinetics of inactivation of the infectivity of the influenza virus by beta-propiolactone have been studied. Rate constants have been determined for inactivation of the A/Leningrad/385 (H3N2) and B/Leningrad/489/80 influenza virus under the action of beta-propiolactone on a virus-containing allantoic fluid and on a purified viral suspension. The data obtained allow calculation of the time required for inactivation of the influenza virus infectivity to a given extent in virus-containing solutions at any initial concentration of beta-propiolactone.

Principles of selective inactivation of viral genome. I. UV-induced inactivation of influenza virus.

Photosensitivity of infectious, haemagglutinating and neuraminidase activities of influenza virus has been determined experimentally. The photosensitivity of infectious activity of type B (strain Hongkong/8/73) influenza virus ws found to be higher than that of type A strains NIB-4 (N3N2-3), Leningrad/399/76 (H3N2-3) and NIB-6 (H1N1). The data obtained may be used for the determination of conditions of UV-irradiation for preparation of UV-inactivated antiviral vaccines.