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Biomedical subjects

S A Bobrovnik

Publications and source records attributed to S A Bobrovnik.

At least 19 recordsLinked to original sources
PubMed2003

Determination of antibody affinity by ELISA. Theory.

New approaches for the measurement of antibody affinity by ELISA are suggested and considered theoretically. It was shown that not only more precise and more convenient in comparison to that suggested earlier, but also more informative graphical representation of the experimental data in the appropriate coordinate could be used for evaluation of antibody affinity. The following cases were considered: (i) determination of antibody affinity for one kind of univalent antibodies, (ii) determination of antibody affinity for one kind of bivalent antibodies, (iii) determination of antibody affinity for two kinds of univalent antibodies, which are in a mixture, and (iv) determination of antibody affinity for two kinds of bivalent antibodies, which are in a mixture. Advantages and disadvantages of the different approaches are discussed.

Antibodies↗
PubMed2003

Ligand-receptor interactions: a new method for determining the binding parameters.

A new experimental procedure and new plot coordinates that allow determination of the binding parameters of ligand-acceptor interaction have been proposed. Instead of titration of a constant concentration of receptors with changing concentrations of ligand, as requested by the well-known methods of Klotz and Scatchard, a series of sequential dilutions of the reacting ligand-receptor mixture is suggested. This allows the application of a new coordinate system that transforms the binding isotherms into straight lines. The case of one acceptor with two classes of receptors with different binding constants is also considered briefly, where the correspondent graphs are nonlinear. It is suggested that in some cases this approach can be a simple and convenient substitute of the broadly used methods of Klotz and Scatchard.

Binding Sites↗
PubMed2002

Ligand-receptor interaction. Klotz-Hunston problem for two classes of binding sites and its solution.

The problem of the affinity and quantity determination of two classes of binding sites for ligand-receptor interaction using either Scatchard or Klotz plots was considered. Klotz and Hunston previously solved this problem only for the case of a representation of experimental data using the Scatchard plot. Since their publication, it was the common view that only the use of the Scatchard plot allows solving this problem. However, in some cases, using the Klotz plot is more convenient for a representation of experimental data concerning ligand-receptor interaction, though usually, this plot was used only for the evaluation of receptor affinity with one class of binding sites. In the present paper, it was demonstrated that Klotz plot also could be used for the evaluation affinity and quantity of two classes of binding sites.

Binding Sites↗
PubMed2000

Determination the rate constants of some biexponential reactions.

Reactions that are described by biexponential functions are typical for many biological processes. The kinetics of these reactions is described by transcendental irrational equations interconnecting the reagent concentrations, time and rate constants. Meantime, their graphical representation in the semi-logarithmic coordinates can be decomposed into two straight lines that intercept at some angle. New simple methods for asymptotic numerical solution of the equations describing these reactions are suggested. These methods permit determining the rate constants using the kinetic data of initial substance concentration, which transform into final product according to a two-component model, a sequential model or a competitive model.

Kinetics↗
PubMed1998

Determination of kinetic parameters for both reversible and irreversible first-order reactions.

Two methods of calculating the rate constant(s) and the total amount of final product for both irreversible and reversible first-order reactions have been developed. These methods are based on the analytical solution (for a special case) of the system of transcendental equations, which describe the reaction kinetics. The methods are simpler and more convenient to use than the earlier proposed graphic methods of Guggengeim and Kezdy-Swinbourne.

Biochemistry↗
PubMed1991

[The determination of antigen-specific immune complexes by an immunoenzyme method].

The methodological approach permitting the detection of immune complexes containing specific antibodies to a definite antigen in the enzyme-linked immunosorbent assay (ELISA) is described. The basic conditions of the assay were optimized. Immune complexes were precipitated from blood serum with 3.5% polyethylene glycol 6000 for 4 hours. The precipitate thus obtained was dissolved and incubated in polystyrene plates with immobilized antigen at 37 degrees C for a long time (at least 6 hours) in a humid chamber. The amount of bound antibodies, determined by ELISA techniques, was conjectured from the level of antigen-specific immune complexes. The proposed approach can be used in the immunodiagnosis of infectious diseases.

Animals↗
PubMed1991

[The dynamics of the humoral immune response to mycobacterial antigens in mice].

The main regularities of humoral immune response to mycobacterial antigens have been studied in experiments on BALB/c mice immunized with live and thermoinactivated Mycobacterium tuberculosis, var. bovis. As shown in this study, the maximum level of serum antibodies to mycobacterial antigen is achieved in two weeks after immunization irrespective of the dose and viability or mycobacteria, then follows a decrease in the antibody level. The absence of uniformity in the dependence of primary immune response and the formation of immunological memory on the dose and viability of mycobacteria has been demonstrated.

Animals↗
PubMed1991

[The formation of delayed hypersensitivity to mycobacterial antigens].

In experiments on guinea pigs and BALB/c mice delayed hypersensitivity to mycobacterial antigens was induced by the sensitization of the animals with live BCG or killed Mycobacterium bovis or M. avium in incomplete Freund's adjuvant. In the study of the dynamics of the development of skin reactivity to tuberculin some advantages of the sensitization of guinea pigs with live mycobacteria were revealed, while after the revaccination of the animals no development of secondary cell-mediated immune response was observed. The immunization of guinea pigs with atypical mycobacteria prior to their sensitization with BCG was found to lead to the development of higher skin reactivity to allergen prepared from atypical mycobacteria than skin reactivity to tuberculin.

Animals↗
PubMed1990

[Isolation of antibodies against species-specific M. bovis antigens].

Tuberculin PPD antibodies were isolated from hyperimmune rabbit serum by affinity chromatography. They were crossover depleted for elimination of antibodies specific to common (with atypical mycobacteria) antigens. Antibodies to M. bovis species-specific antigens may be used for preparing an immunosorbent and affinity chromatographically isolating the antigens from tuberculin PPD.

Animals↗
PubMed1990

[The role of T-lymphocytes in the development of a humoral immune response to the corpuscular antigen of Staphylococcus aureus].

The dependence of humoral immune response and the formation of immunological memory to corpuscular staphylococcal antigen (CSA) on the T-system of immunity was studied in experiments on B-mice and on mice with the congenital absence of the thymus (nude). Primary and secondary immune response to CSA in athymic mice was found to be considerably less than in normal animals. After the repeated immunization of genetically athymic mice the pronounced secondary reaction of the formation of antibodies to CSA was observed. As shown in this investigation carried out with the use of adoptive transfer techniques, the induction of memory B-cells to CSA may occur in animals with congenital or experimentally induced T-immunodeficiency. The conclusion was made on the T-dependence of humoral immune response to CSA, the formation of immunological memory to this antigen being relatively T-independent.

Animals↗
PubMed1989

[The role of the bone marrow in forming an immunological memory to Staphylococcus].

The dynamic study of antibody formation in the bone marrow tissue of mice immunized with corpuscular staphylococcal antigen was made. A single intravenous injection of this antigen to the animals produced no essential changes in the number of antibody-forming cells in the bone marrow, their repeated immunization led to the involvement of the bone marrow in the anamnetic reaction, which was manifested by the accumulation of a great number of plasmocytes synthesizing antibodies to staphylococci in bone marrow tissue. The relative contribution of the bone marrow to systemic antibody formation essentially increased at later stages of secondary immune response. The possible biological significance of the regularities and the practical importance of the data revealed in this investigation are discussed.

Animals↗
PubMed1988

[Determination of rate constants for the antigen-antibody reaction. Kinetic characteristics of interaction of soluble and corpuscular antigen with specific antibodies].

Using the previously developed procedure, the rate and equilibrium constants for the interaction of antibodies with soluble or corpuscular antigens were determined. Cow milk casein was used as a soluble antigen, while heat-inactivated Staphylococcus aureus cells--as a corpuscular antigen. The values of kinetic constants for the above reactions are close to those for various antigen--antibody pairs obtained by other investigators.

Antigen-Antibody Reactions↗
PubMed1988

[Determination of rate constants of antigen-antibody reaction. A theory].

A new method of determination of rate constants for antigen-antibody interactions is proposed. This method is based on a solid phase immunoenzymatic analysis of the dynamics of elution of immobilized antigen-bound antibodies in the presence of a free antigen. The kinetics of this process is described by a system of differential equations, whose solution results in expression defining the dynamics of antibody interaction with immobilized and free antigens. Simple formulas were derived for the calculation of the rate and equilibrium constants for the antibody-antigen reaction on the basis of experimental kinetic curves. The use of theoretical kinetic curves for antibody elution showed that these formulas reflect with a high degree of accuracy the kinetic properties of the reaction under study.

Antigen-Antibody Reactions↗
PubMed1988

[The antigen-antibody reaction and its inhibition].

The sera of intact and immune animals contain factors capable of inhibiting the interaction of antibodies with the homologous antigen. These agglutination inhibiting (AI) factors not only block the antigen, thus competing with antibodies, but may induce the dissociation of the antigen-antibody complex. Heating of antisera at 60-63 degrees C leads to an increase in the activity of AI factors. The phenomenon of "prozone" in the agglutination test appears to be explained by the presence of AI factors in sera.

Agglutination Tests↗
PubMed1986

[Mechanism of formation of antibody production stimulating ability of bone marrow cells of mice immunized with staphylococci].

The mechanism of the increase in immune response to particular staphylococcal antigen was studied in CBA and BALB/c mice injected by primed bone marrow cells (BMC). It was found that immunostimulatory effect of immune BMC is not mediated by macrophages or T cells, but is associated with staphylococcus-specific B memory cells present in the pool of primed BMC. Splenectomy performed in donor animals prior to immunization did not abolish the induction of stimulating BMC activity. It was concluded that primed B lymphocyte migration from spleen into bone marrow is not obligatory for the induction of staphylococcus-specific immunological memory in the bone marrow.

Animals↗
PubMed1986

[Immunosuppressor role of staphylococcal protein A].

The removal of protein A from the surface of staphylococci by means of proteolytic enzymes increases the immunogenic properties of staphylococci. Staphylococci containing protein A are less effective in mediating the immunological memory than those treated with proteolytic enzymes. The conjugation of protein A with staphylococci treated with proteolytic enzymes leads to the decrease of the immunogenic properties of staphylococci. Protein A not bound to staphylococci also suppresses antistaphylococcal immune response. The protective properties of corpuscular staphylococcal antigen are increased after the removal of protein A from the surface of staphylococci by proteolysis.

Animals↗