[Production and characterization of a panel of monoclonal antibodies to Toxoplasma gondii antigens]. / Poluchenie i kharakteristika paneli monoklonal'nykh antitel k antigenam Toxoplasma gondii.

A representative collection was obtained containing 68 monoclonal antibodies (MAB) to Toxoplasma gondii antigens, which was characterized by the binding with the below fractions of tochizoites in the immune-enzyme assay (IEA) and immunoblotting (IB): membrane (MEM), somatic (water-soluble, SOM) and excretory-secretory (ES). Most of MABs were produced to MEM antigens (43), 6 MABs reacted with the somatic fraction, and 3 MABs reacted with both fractions. Two MABs to ES antigen were detected in the latter group. An analysis of MABs in concurrent IEA and IB revealed the immune-dominant proteins of the MEM and SOM fractions of antibodies to T. gondii tochizoites (p30 and p27, respectively). The presence of 2 non-overlapping antigenic determinants was shown for p30. Further research would detect MABs that could be used in the diagnosis of toxoplasmosis.

[Sensitizing and virus-neutralizing characteristics of goat immunoglobulins to Ebola virus]. / Sensibiliziruiushchie i virusneitralizuiushchie svoistva koz'ikh immunoglobulinov protiv virusa Ebola.

Sensitizing and virus-neutralizing properties of IgG isolated from the sera of goats immunized with Ebola virus and a relevant gammaglobulin prepared by ethanol fractionation were compared. The ratio of the virus-neutralizing activities of subclasses IgG2, IgG1a, and IgG1b was 100:10:1. Anaphylactogenic activity of IgG2 in the immediate type hypersensitivity test in guinea pigs was 2-fold lower than that of IgG1a and IgG1b. Goat gammaglobulin to Ebola virus, consisting from IgG2 antibodies by more than 50%, possessed virus-neutralizing and sensitizing characteristics compatible to IgG2.

[Investigation of the protein composition and immunochemical properties of Toxoplasma gondii excretory and secretory antigen]. / Izuchenie belkovogo sostava i immunokhimicheskikh svoistv ékskretorno-sekretornogo antigena Toxoplasma gondii.

The major proteins of T. gondii excretory and secretory antigens (ESA) obtained during cultivation of tachyzoites by using cultured Vero cells were shown to have molecular weights of 79, 70, 57, 48, 36, and 29 kD. ESA and somatic antigen immunoblotting demonstrated that there were noticeable differences in the immunoactive proteins of these antigens. The antibodies of the sera of patients with toxoplasmosis mainly interacted with ESA proteins having molecular weights of 79, 70, 57, 48, 36, and 29 kD, 57-kD ESA protein antibodies being present on the immunoblots of all the tested sera. When ESA was used as an antigen during enzyme immunoassay, it showed a high sensitivity in the detection of IgM antigens in congenital toxoplasmosis. At the same time, ESA identified the antibodies of this class in the sera of healthy donors much infrequently than somatic antigen (p < 0.05).

[Composition of circulating immune complexes in acute toxoplasmosis]. / Izuchenie sostava tsirkuliruiushchikh immunnykh kompleksov pri ostrom toksoplazmoze.

The circulating immune complexes (CIC) that form in the hot just in early Toxoplasma gondii invasion can be present in the blood bed for a while. At the same time, the data on the antigenic composition of CIC in toxoplasmosis are fragmentary and rather contradictory. The investigation used enzyme immunoassay (EIA) to detect specific CIC that contain antigens to T. gondii tachyzoites in the sera of different populations and studied their antigenic composition by immunoblotting after 2-6% polyethylene glycol 6000-induced deposition. Examining 464 sera from groups of individuals with varying-stage T. gondii invasion indicated CIC in each, but showing their different frequency. CIC were virtually present in all sera from children who had been diagnosed as having congenital toxoplasmosis. In groups of seropositive pregnant women, CIC detection rates were noticeably higher in the samples showing both IgG and IgM antibodies (40.2 and 66.4%, respectively). CIC were also revealed in 9.8% of the seronegative blood donors; however, immunoblotting failed to confirm that they had no components that specifically reacted with T. gondii tachyzoite antigen antibodies. There were some differences in the composition of CIC in the serum yielding positive results in both EIA and immunoblotting. The serum CIC from pregnant women that exhibited only IgG antibodies contained mainly T. gondii antigens having molecular weights of 67 and 30 kD. The serum CIC from children with congenital toxoplasmosis and from pregnant women with serologically detected IgM antibodies to Toxoplasma antigens were found to contain 55-58-, 48-, 44-, 38-, 30-, and 26-kD components. The same molecular weight proteins were detected by electrophoretic studies of Toxoplasma excretory-secretory antigen (ESA). Comparing the findings suggests that in acute toxoplasmosis, the circulating complexes mainly contain ESA of the tachyzoites which appear in human blood just at the onset of invasion. Thus, this study demonstrates that specifically CIC are detectable in the sera of individuals infected with T. gondii and their antigenic composition varies with the stage of disease. In the authors' opinion, the detection of specific CIC and the determination of their antigenic composition may be serve an additional test in diagnosing acute toxoplasmosis.

[The detection of antibodies to the trophozoite antigens of Lamblia by an immunoenzyme method]. / Vyiavlenie antitel k antigenam trofozoitov liamblii immunofermentnym metodom.

Whether purified antigens of Lamblia intestinalis trophozoites can be used to detect these antibodies by immunoassay. The drugs of immunodominant Lamblia antigens were prepared by anion-exchange chromatography of solubilized trophozoite components and they are mainly presented by proteins having molecular weights of 70, 56, and 49 kD. Immunoassay using these antigens revealed antibodies to Lamblia trophozoite antigens in sera of 87.6% of patients with lambliasis (its diagnosis was established on the basis of microscopic data on the duodenal content) and only in 16.2% of clinically healthy blood donors. Twenty six sera from patients with trichomoniasis having high levels of antibodies to trichomonad antigens were studied to evaluate the specificity of this method for detection of antibodies. It has been found that the proportion of subjects in this group who have also antibodies to Lamblia antigens does not greatly differ from that of healthy blood donors (19.2 and 16.2, respectively).

[Developing methods of specific heterologic immunoglobulins preparation for urgent prevention of Ebola fever and study of their properties]. / Razrabotka metodov polucheniia spetsificheskikh geterologichnykh immunoglobulinov dlia ékstrennoi profilaktiki likhoradki ébola i izuchenie ikh svoistv.

Methods for preventing and treating Ebola virus hemorrhagic fever are not still available despite the fact that this virus have been studied for 20 years. Methods of immunization of the animals (sheep, goats) non-susceptible to Ebola virus with live virus preparations were developed to obtain the hyperimmune anti-Ebola virus sera required to have highly immune antivirus gamma-globulins. These methods made it possible to obtain the immune sera having high virus-neutralizing antibodies. Caprine immunoglobulins were obtained from sera by fractionation of immune sera by Kohn's method. The neutralization indices of the immunoglobulins obtained were at least Ig. When administered in the first hours of infection, the protective effect of these preparations was shown on guinea pigs infected with LD50 of the strain pathogenic to the animals. Preclinical trials of these immunoglobulins on laboratory animals and clinical trials on volunteers were performed. The preparation was used as a preventive agent when accidents took place at the laboratory working with Ebola virus. The similar preparation from equine sera having high neutralizing and protective properties was elaborated at the Virological Center, Microbiological Institute, Russian Ministry of Defense. Its prophylactic efficiency was also shown in infected gamadrias.

[An immunochemical study of the antigens from Toxoplasma gondii tachyzoites obtained in different cultivation systems]. / Immunokhimicheskoe izuchenie antigenov takhizoitov Toxoplasma gondii, poluchennykh v razlichnykh sistemakh kul'tivirovaniia.

The protein composition and immunochemical properties of Toxoplasma gondii tachyzoites cultured on Vero cells and on mice were studied. Despite the fact that the main components of both preparations were shown to be proteins with molecular weights of 47, 34, 24, and 22 kDa, Toxoplasma-infected human sera antibodies interact mainly with the antigens of 66, 62, 57, 42, 38, 37, 36, 31, and 24 kDa. Comparing efficiency of enzyme immunoassay using the antigens of the tachyzoites obtained in different culture systems showed that the preparation of cultured Vero cells is similar to those of peritoneal exudates from infected mice and may be successfully used for the detection of antitoxoplasma antibodies in the sera of infected subjects.

[Immunoenzyme method of the determination of human chorionic gonadotropin using polyclonal antibodies]. / Immunofermentnyi metod opredeleniia khorionicheskogo gonadotropina cheloveka s ispol'zovaniem poliklonal'nykh antitel.

The authors developed a method for obtaining highly specific polyclonal antibodies reacting with different sites of human chorionic gonadotropin (HCG) and an immunometrical method for measuring HCG in human biological fluids, based on the use of these antibodies. The sensitivity of the method is 10-15 IU/liter HCG, specificity 100%, no cross reactions with LH or FSH were observed. The method was tried in testing urine samples for HCG in women at 1-2 to 34 weeks of gestations and in one cancer patient with the diagnosis of vesical mole.

[The seroepidemiology of toxocariasis in an opisthorchiasis focus in the western Siberian region]. / Seroepidemiologiia toksokaroza v ochage opistorkhoza zapadno-sibirskogo regiona.

Seroprevalence to Toxocara antigens was studied among Novosibirsk inhabitants and a focus of toxocariasis was found in the southern regions of west Siberia. Analyzing the sera of opisthorchiasis patients revealed antibodies to Toxocara antigens, with high titers (1:800 or more) in 1.80% of cases. Immunoblotting of these sera and those from patients with toxocariasis and opisthorchiasis, which were seropositive in one of the above helminths showed that there were mixed human infections with Toxocara and Opisthorchis in this area.

[Composition and immunochemical properties of goat immunoglobulins against the Ebola virus]. / Sostav i immunokhimicheskie svoistva kzo'ikh immunoglobulinov protiv virusa ébola.

Serum samples containing Ebola Virus neutralizing antibodies were prepared by prolonged immunization of goats with 10% liver homogenate from guinea pigs infected with Ebola virus. Differences in IgG fractions of normal and hyperimmune caprine blood sera were detected. Analytical chromatography on Polysil SA and immunodiffusion showed the presence of three IgG-containing fractions in hyperimmune sera. Immunochemical properties of these fractions were studied by solid-phase enzyme immunoassay and neutralization test. Antibodies to viral antigens were referred to IgG2 and IgG1a, and virus neutralizing properties were found mainly in IgG2 antibodies. Immunoglobulins were isolated from hyperimmune serum by alcohol sedimentation. The principal IgG fraction was found to contain much lower levels of antibodies to guinea pig liver antigens than intact serum, but at the same time it was characterized by a higher neutralization index.