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M I Levi

Publications and source records attributed to M I Levi.

At least 19 recordsLinked to original sources
PubMed1979

[Determination of the concentration of active centers and the antibody heterogeneity index by using the precipitation in fluid reaction].

Equivalence zone in the precipitation test was characterized by the fact that the number of the antigen determinants was equal to the number of active antibodies centres, irrespective of the heterogeneity of the latter. This permits to assess the antibody concentration in the values of the antigen valency. The new method of determination of the antibody heterogeneity index is based on recording the titre of the antigen and antibodies in the equivalence zone.

Animals↗
PubMed1979

[Determination of the internal association constant as a measure of the affinity of erythocyte-fixed antibodies that interact with mono- and multivalent antigens].

The fraction of antibody-bound determinants of a polyvalent antigen is determined by the fraction of free antigen molecules and the valence of the antigen. The internal association constant for antibodies fixed onto erythrocytes can be found by the suspension method, the index obtained in this process being similar when both monovalent and polyvalent antigens are used. The sensitivity of the antibody-erythrocyte diagnostic preparation in the passive hemagglutinin test depends on the affinity of the active centers of antibodies.

Antibodies↗
PubMed1978

[Serological method of detecting the antigens of the causative agent of Sonne dysentery in lysates of the fecal inoculates from patients].

Serological method of detection of Sh. sonnei antigens in the lysates of the patients, fecal cultures is suggested and approved. In the majority of cases of the results of bacteriological and serological methods of study of the feces coincided. Data confirming the specificity of the antibody neutralization test (ANT) in Sonne dysentery are presented. In connection with detection of the screening action of the Vi-antigen of typhoid bacilli there were elaborated additional methods for verifying the specificity of the ANT results. It is recommended to keep agar plates after selection of suspicious colonies during the bacteriological test; the lysate of the microbial crop should be additionally subjected to the ANT, this considerably increasing the percentage of laboratory confirmations of dysentery caused by Sh. sonnei.

Antigens, Bacterial↗
PubMed1978

[Farr's modified method and ways of determining the index of antibody heterogeneity and the mean assoication constant].

The modified Farr's method included mixing of the solutions of a univalent antigen and antibodies, precipitation of the antigen-antibody complexes with semisaturated ammonium sulfate solution, and determination of serological activity of the free antigen in the supernatent fluid. The mentioned modification permitted to determined the heterogeneity index and the mean association constant without resorting to labeled antigens. Besides the standard calculation method, the authors recommed simplified methods of heterogeneity index and the mean association of constant determination.

Antibodies↗
PubMed1977

Cyclic kinetics and mathematical expression of the primary immune response to soluble antigen. VII. The conveyer hypothesis and its mathematical expression.

The conveyer hypothesis is based on the fact that because of clone predetermination, antibody production takes place in an organism without the presence of antigen as a result of natural cell differentiation. Soluble antigen is an analogue of a specific mitogen which gives rise to reproduction mainly of cells carrying on their surface the immunoglobulin receptors to the given antigen. The mathematical model of the conveyer hypothesis takes into account the initial conditions, among them the background level of antibody-producing cells before injection of a soluble antigen, migration of precursor cells in the draining lymphoid organ, and the rate of precursor differentiation, including the rate of the change of the immunoglobulin receptor number on the cell surface. Changes of antigen concentration in blood determine the intensity of precursor proliferation. Comparison of real experiments (intraperitoneal injections of capsular antigen of Pasteurella pestis into inbred mice) with calculations done on the basis of the developed mathematical model shows a definite qualitative resemblance with the kinetics of antibody-producing cells and free antibodies as well as with the decrease of free antigen concentration in blood. In spite of some differences between model experiments and real experiments the conveyer hypothesis and its mathematical model appear suitable for describing the primary immune response of mice immunized with low doses of capsular antigen of Pasteurella pestis.

Animals↗
PubMed1977

[Determination of the concentration of antibody reactive centers using a standard antigen and erythrocytic antigen].

The concentration of the reactive centres of the antibodies in the preparation under study can be determined with the aid of an antibody erythrocytic diagnostic agent. A mathematical substantiation of the suggested method and definite examples of its use are presented. The sensitivity of the serological method of determination of the concentration of the reactive centres of the antibodies largely depended on the valency of the antibody erythrocytes and the heterogeneity of the antibodies. This method permits to determine the sum of the reactive antibody centres equivalent to the definite concentration of the molecules of the standard antigen whose valency remains unknown.

Binding Sites, Antibody↗
PubMed1977

[Use of serologic reactions for determining the concentration of the determinants of an antigen and its valence].

By the serological tests with the erythrocytic diagnostic agents it is possible to estimate the concentration of the determinants in the antigenic preparation under study. For this purpose it is necessary to have at one's disposal the data on the molecular weight and concentration of the reference antigen, valence of erythrocytes loaded with the antigen or antibodies, and antibody heterogeneity index. If these values are known, then one can calculate the concentration of antigenic determinants in terms divided by the valence of the reference antigen. With the aid of pure antibodies preparation obtained with the immunosorption procedure it is possible to measure the determinant concentration of the antigen tested and the valence of the reference antigen. For the capsular antigen of plaque bacilli the valence was estimated by two independent methods and in both cases it was close to 10. The valence of the reference capsular antigen permits to calculate the concentration of the antibody molecules in the hyperimmune sera without isolation of pure antibodies.

Animals↗
PubMed1976

[Use of erythrocyte diagnostic agents for the determination of integrative association constants].

The authors described a method of determination of integrative association constant differing from intrinsic association constant by the value of the valency of macromolecular antigen. The method is based on the using of erythrocytes on whose surface one of the components is fixed, whereas the other is in free state. Application of equations was demonstratedon a number of examples with determination of integrative association constant. The data obtained permitted to assess qualitative peculiarities of the antigenic and antibody erythrocytic diagnostic agents.

Antibodies↗
PubMed1976

A stable antibody-sensitized erythrocyte diagnostic preparation for detection of rhinovirus type 17 and its antibody.

A diagnostic preparation was obtained by sensitization of formalinized sheep erythrocytes with antibody to rhinovirus type 17. This preparation was agglutinated in the presence of relatively high concentrations of type 17 but not other types of rhinovirus. It could also be used for detection of antibody to rhinovirus type 17 in the antigen neutralization test, the antibody levels determined in this way being similar to those found by conventional virus neutralization tests in cell cultures.

Animals↗
PubMed1976

[Determination of antibody affinity using threshold values of serum activity in the passive hemagglutination test].

Agglutination of erythrocytes of the antigenic diagnostic agents with the IgG antibodies is attributed to the fact that the reactive centres of the same molecule of the antibody attached to the antigenic determinants located on different erythrocytes. A possibility of agglutination of erythrocytes under conditions of the maximal dilution of the immune serum depended on the number of molecules located on a single erythrocyte. When the erythrocytes are sensitized with the optimal dose of the antigen those serum antibodies are involved in the passive hemagglutination test (PHAT) which are characterized by the mean integrated association constant. When the antibodies participate in the PHAT with several batches of the erythrocytic diagnostic agent characterized by an average number of the antigen molecules on a single erythrocyte there appears a possibility of determining the extent of heterogeneity of the antibodies. Not only the amount of antibodies, but also their affinity can be ascertained by the PHAT, and also the heterogeneity of antibodies can be evaluated.

Antibodies↗
PubMed1976

[Normal antibodies and immunologic reactivity].

Antibodies to the capsular antigen of plague causative agent were found in the serum of many nonimmunized mice of 6 strains, but none were found in mice of the DBA/2 strain. After the administration of the capsular antigen to mice of different strains cells forming the antibodies to the antigen administered were revealed in a quantitative correlation with the natural antibody level. An association was revealed between the level of natural antibodies and the number of antibody-forming cells in the spleen of nonimmunized mice; it could be described by an equation almost all of whose members represented constant values with a definite quantitative characteristics. To check the suggested equation the concentration of immunoglobulins in the blood of mice was compared with the number of plasma cells in the spleen; a satisfactory correlation was revealed between them.

Animals↗
PubMed1975

Cyclic kinetics and mathematical expression of the primary immune response to soluble antigen. VI. The possibility of prediction of plasma cell reaction in the spleen of mice immunized with soluble antigen.

A mathematical expression of the accumulation of the plasma cells in the spleen of CBA mice immunized intraperitoneally is presented. The dependence of the plasma cell reaction in the spleen on the kinetics of antigen concentration in the blood was confirmed. For the transition from antigen to plasma cells, index A was proposed. The mean values of index A were used for comparison of the calculated and experimental values of the plasma cell reaction and the recorded differences were not great. In a similar way, index A was used for prediction of plasma cell accumulation in the spleen of animals, immunized with a mixture of two soluble antigens -- capsular antigen of Pasteurella pestis and complete antigen of Francisella tularensis. The calculated values of plasma cell reaction corresponded to experimental values.

Animals↗
PubMed1975

[Approximate assessment of the successfulness of bacteriological and serological methods of studying rodents in natural plague foci].

On the basis of the study of two mathematical models of the epizootics the authors suggest a criterion for the determination of the correlation of the value of the results of bacteriological and serological examination of rodents in the natural foci of plague. In accordance with the criteria obtained an evaluation was made of this correlation for Pallasiomys meridianus of the left and right banks of the Volga. It appeared that the calculated assessment of the value of the results of the two methods under study correlated satisfactorily with the data obtained in practice during the epizootologic examination of the Volgo-Urals natural focus of infection.

Animals↗
PubMed1975

[Utilization of a solid nutrient medium for the serological method of detecting the causative agent of typhoid in patients' feces].

The causative agent of typhoid fever can be revealed in feces of patients not only by the bacteriological, but also by the serological method, if the material is preliminarily grown on hard nutrient media; Ploskirev's medium proved to be the optimal. It is suggested that microbial cultures left on the ager in Petri dishes after the bacteriological study should be used for bacteriological analysis. In a number of cases it was possible to reveal the causative agent of typhoid fever in feces by the serological method, although no coproculture was isolated bacteriologically.

Antigens, Bacterial↗
PubMed1975

[Serological study of nontriturated fleas following preliminary cultivation of the plague microbe].

Under experimental conditions there was shown a possibility of serological study of nontriturated fleas for the presence of Past. pestis. Hottinger's broth with gentian-violet ((0.0003%) sodium sulfite (0.03%) and a surfactant--O (see article)-7 (3%) served as the growing medium. After the nontriturated fleas were grown for 48 hours at 37 degrees C the capsular antigen was detected with the aid of the passive hemagglutination and antibody neutralization tests. Detection of the capsular antigen in the growing medium pointed to the presence of Past. pestis in the fleas. To test the serological method of study the nontriturated fleas, the insects were collected in the colonies of Rhombomys opimus Licht. at the epizootic territory. The collected fleas were divided into portions (each portion contained not more than 20 fleas). Half of the portions of each collection was studied after trituration by the usual bacteriological method, and another--by serological method without trituration of the insects. In examining the parallel portions (a total of 2400 portions, about 32 000) it appeared that positive results were obtained by both methods with about the same frequency.

Animals↗
PubMed1975

[The possibility of predicting the degree of plasmacyte reaction in response to administration of soluble antigen to mice].

The work is devoted to the mathematical description of the accumulation of plasma cells in the spleen of CBA mice immunized intraperitoneally. A dependence between the dynamics of the soluble antigen concentration in the blood and the plasmocytic reaction in the spleen was confirmed under experimental conditions. Index A was suggested for detection of a change from the antigenic function to the accumulation of plasma cells. The mean values of index A were used to compare the calculated values of the plasmocytic reaction and the experimental data; differences between these values were insignificant. Analogously index A was used for predicting the accumulation of plasma cells in the animals to which a mixture of the two soluble antigens (a capsular antigen of the causative agent of plague and a complete antigen of the causative agent of tularemia) was administered. The calculated values of the plasmocytic reaction in this experiment satisfactorily correlated with the data obtained experimentally.

Animals↗