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Comparative study of widely distributed on Russian market commercial test-systems for HBsAg detection by enzyme immunoassay was performed. Panel of serum samples containing mutant forms of HBsAg was developed for the study. It showed that only 2 out of 7 studied test-systems are able to detect mutant forms of HBsAg with the same sensitivity as "wild-type" forms of HBsAg. Test-systems based only on monoclonal antibodies did not detect HBsAg with G145R substitution in concentration 5 ng/ml. The study confirms the relevance of problem of HBsAg-mutants detection for hepatitis B immunodiagnostics.

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Mice monoclonal antibodies against lypopolysaccharides (LPS) of Brucella abortus has been obtained and characterized. The antibodies detected LPS of B. abortus, B. melitensis and B. suis with high sensivity and specificity and did not react with LPS of Yersinia enterocolitica O:3, Y. enterocolitica O:9, Salmonella typhimurium, and Francisella tularensis. It has been shown that interaction of monoclonal antibodies and LPS of Brucella species can be critically dependent from buffer system. Obtained monoclonal antibodies allowed to develop highly sensitive assay which was able to detect antigens of Brucella species in concentrations 0.05 - 0.1 ng/ml. The assay can be used for detection and identification of Brucella species.

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Algorithm of serologic screening for HBsAg-mutants in hepatitis B virus (HBV) carriers with high level of HBsAg was developed which is based on the detection of defects of interactions of serum HBsAg with monoclonal anti-HBs realizing as a decrease of ELISA sensitivity in 10 times or more during serial 10-fold dilutions. During 1st stage commercial test-systems based on monoclonal antibodies was used to select serum samples with discrepancy of test results. During 2nd stage HBsAg contained in selected sera was analyzed by the panel of monoclonal and polyclonal anti-HBs conjugates using decrease in ELISA sensitivity as a criterion. Serum samples from 2510 chronic carriers of HBV with high level of HBsAg were studied. 19 samples with discrepant results were found. Subsequent characterization of HBsAg with panel of 11 monoclonal and 1 polyclonal conjugates allowed to distinguish groups of sera with specific serologic "portraits". Atypical features of HBsAg were confirmed by genotyping 9 of 19 samples. Analysis of primary nucleotide sequence revealed serologically meaningful mutations in S-gene of HBV in all 9 isolates: 3 of them contained substitution mutation G145R, 5--S143L, and one--T143M. Distribution of mutations in HBsAg corresponded with specific serologic "portraits". Prevalence of HBsAg mutations in HBV carriers with high level of HBsAg was assessed for the first time: prevalence of G145R, S143L/T143M mutations, and all serologically atypical variants was 0.12%, 0.24%, and 0.76% respectively. Developed algorithm was proposed for epidemiologic monitoring of HBsAg-mutants of HBVand control of diagnostic test-systems.

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The two-stage control system, ensuring the high quality of serological investigations in the network of screening laboratories in Moscow was developed and introduced into practice. At the first stage the entry control of the quality of the test system for the detection of HbsAg, coming to the screening laboratories, is made in the reference laboratory with the use of specially developed "representative" panels, as well as the test systems for comparison ("reference" test systems). Then "minipanels" are formed from specimens included into the "representative" panels, which are used for the evaluation of the quality of laboratory investigations made in the screening laboratories. The high quality of such system for controlling the quality of the detection of HBsAg in the screening laboratories of Moscow is shown.

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A simple and economic scheme for the purification of HBsAg has been developed: step I--immunosorption with the use of a cellulose suspension with immobilized purified anti-HBs, and step II--isopycnic ultracentrifugation through CsCl. This method yields a 300-fold purified HBsAg, its harvest being 75%. An erythrocytic immunodiagnosticum for the passive hemagglutination test has been prepared on the basis of this purified HBsAg; the sensitivity of the test with this immunodiagnosticum is but slightly inferior to that of radioimmunoassay. The specificity and immunogenicity of the resultant HBsAg preparation has been tested by rabbit immunization. The obtained highly effective sera contained no antibody to human proteins. The results recommend the suggesman proteins. The results recommend the suggested method for wide practice.

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It has been previously established that an intravenous injection of a protein antigen solution into mice primed with the same antigen in the form of a protein-cellulose complex induces an intensive antibody production (up to 10,000 antibody-forming cells/10(6) splenocytes and up to 3 mg of antibodies/ml of serum). The present study has shown that secondary immune response can be considerably enhanced if large amounts of the antigen are administered intraperitoneally in a protein-cellulose complex during secondary immunization. In these experiments the mean number of antibody-forming cells was 50.000/10(6) splenocytes and the antibody serum level averaged 10 to 12 mg/ml. The effect persisted for a long time: as late as on day 80 the antibody concentration was 2 mg/ml of serum.

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New microcarriers for the growth of animal cells have been synthesized and studied. The preparations are porous cellulose beads, modified by diamines. Spreading and growth of L cells, MEVO and HETR cells on these beads were observed. As a result of the cultivation the number of animal cells increased 5-10-fold.

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Clonal cell lines were isolated from rat hepatoma McA-RH7777 to study expression of alpha-fetoprotein (AFP) in these clones. AFP contained by the cells was determined by immunofluorescent and immunoperoxidase staining, while AFP secreted into the medium by aggregate-hemagglutination and immunoisotachophoresis. The existence of the clones that drastically differ in the intensity of AFP synthesis was demonstrated, with these clones being implicated in the monitoring of AFP synthesis. The differences between the clones gradually diminished in the course of long-term cultivation. It was also shown that the clones under consideration secreted, apart from AFP, at least 8 proteins of adult rat serum. One of the proteins was identified as transferrin. No albumin was detected in the cultural media tested. The level of AFP production did not correlate with the synthesis of other serum proteins and thus seems likely to be controlled by an independent mechanism.

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Population aspects of specific secreted proteins (alpha-fetoprotein and serum albumin) were analyzed in the cultured human embryo hepatocytes (6 to 12 weeks' gestation). A method based on local hemolysis in gel of sheep erythrocytes conjugated with antibodies specific of proteins in question. The great majority of individual hepatocytes synthesized both proteins.

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The authors determined beta1-G-globulin (beta1GG) in the sera of patients with different malignant tumours and of normal donors by means of the immunodiffusion method (ID) and immunoautoradiography (IAR). In the ID-negative sera beta1GG was revealed by means of IAR in 7 out of 8 patients with chorionepithelioma of the uterus and in 1 out of 7 patients with teratomblastoma of the testis before the treatment. After the treatment the beta1GG was determined in 7 out of 21 patients with chorionepithelioma of the uterus. At the early stage of trophoblastic tumours of the uterus beta1GG could be found in 77.7% of cases by means of IAR and in 16.8% of cases by means of the ID method.

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