Tag Archives: polyreactive immunoglobulins
Thermodynamics of interaction between polyreactive immunoglobulins and immobilized antigen
S. A. Bobrovnik1*, O. V. Ogloblya2, M. O. Demchenko1, S. V. Komisarenko1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2ESC Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Ukraine;
*e-mail: s-bobrov@ukr.net
Received: 22 April 2021; Accepted: 22 September 2021
In order to determine thermodynamic parameters of the interaction between polyreactive immunoglobulins (PRIGs) and immobilized antigen, several of experimental kinetic curves of PRIGs binding to immobilized ovalbumin were obtained at different temperatures. This allowed determining the rate constants for every step of the binding process for each temperature. Then, using appropriate equations, thermodynamic parameters, such as activation energy, enthalpy, entropy, and standard free energy (Gibbs energy), were calculated. Thermodynamic values obtained show that the main energy consuming step in the study process of PRIGs bindingis the transformation of “inactive” PRIGs into “active” PRIGs, i.e. formation of hydrophobic patches on the surface of PRIGs molecules. In contrast, the following step of the binding of “active” PRIGs to an immobilized antigen is not an energy dependent process.
Kinetics of interaction between polyreactive immunoglobulins and antigen
S. A. Bobrovnik1*, O. V. Ogloblya2, M. O. Demchenko1, S. V. Komisarenko1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2ESC “Institute of Biology and Medicine”, Taras Shevchenko National University of Kyiv, Ukraine;
*e-mail: s-bobrov@ukr.net
Received: 28 January 2020; Accepted: 25 June 2020
A number of experimental kinetics curves of mice polyreactive immunoglobulins (PRIGs) binding to ovalbumin immobilized on immunologic plates were obtained at different temperatures. Analysis of these curves allowed us to conclude that the model of PRIGs interaction with antigens proposed by us earlier and consisted on PRIGs activation (i.e. exposition of hydrophobic patches on PRIGs surface) and either sequential binding to antigen or inactivation was is in a good agreement with the experimental data obtained in this study. We have designed a method of the rate constants evaluation from experimental binding curves. It was found that the rate constant of the activated PRIGs binding to immobilized antigen did not depend on temperature. The rate constant of PRIGs activation occurred to be depend on temperature more strongly than the rate constant of PRIGs inactivation. We have concluded from the acquired dependences that at 37°С the number of activated PRIGs was 15 times higher than that at 0°С.
Kinetics of interaction between polyreactive immunoglobulins and antigen. The theory
S. A. Bobrovnik, M. O. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@ukr.net
Received: 14 February 2019; Accepted: 17 May 2019
Dynamics of association between polyreactive immunoglobulins (PRIGs) and immobilized antigens is considered on the base of our model of PRIGs-antigen interaction, which was suggested by us earlier. This process of PRIGs binding to an immobilized antigen was described with a system of differential equations. The solution of this system of differential equations gives mathematical expressions that relate the dynamics of the reactant concentrations and time of the reaction. Using Microsoft Excel program the theoretical curves were calculated and plotted that described the dynamics of “active”, “nonactive” PRIGs in solution as well as PRIGs that were bound to an immobilized antigen. Conclusions drawn by us earlier about very high dependence of reaction PRIGs with an antigen from temperature were confirmed.
Effect of trifluoroethanol on antibody reactivity against corresponding and nonrelated antigens
S. A. Bobrovnik, M. O. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@ukr.net
The ability of antibodies to switch between specific and nonspecific recognition of antigens under various factors is the key issue. Here we demonstrate that 2,2,2-trifluoroethanol (TFE) is one of these factors influencing the ability of monoclonal antibodies to react specifically with corresponding antigen (ovalbumin) and transforming them into polyreactive immunoglobulins (PRIGs) that are strong but nonspecific binders with various antigens. Such switching of antibody reactivity is nonlinear and even nonmonotonous function of TFE concentration and depends strongly on incubation time and temperature. At room temperatures (25 °C) the specific antibodies under 30% TFE action are transformed into PRIGs. However, at 0 °C the variation of antibody reactivity is complicated. TFE is known as the alcohol with one of the strongest proton-donor abilities in hydrogen bonding and its effect is probably in binding to specific sites that switch the antibody recognition ability.
Avidity and competitive inhibition of binding native and chaotropically modified immunoglobulins with protein and glycolipid antigens
N. V. Khimich, A. I. Gоrdienko
State Institution S. I. Georgievsky Crimea State Medical University, Simferopol, Ukraine;
e-mail: uu4jey@csmu.strace.net
It is established, that native and chaotropically modified immunoglobulins essentially differ by avidity and character of competitive inhibition of binding with protein (оvalbumin), glycolipid (lipopolysaccharides) antigens and native double-string DNA. Apparently, it is connected with structural and functional distinctions of their antigen-binding centres.
Fundamental differences between natural antibodies and polyreactive immunoglobulins
S. A. Bobrovnik, M. A. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@bk.ru
A problem of similarity and differences between so-called polyreactive immunoglobulins (PRIGs) and natural antibodies (NAbs), capable of cross-reacting with some structurally dissimilar antigens, has been considered. The analysis of mechanisms of an unspecific interaction between PRIGs or NAbs and antigens evidences for the fact that essential differences exist between these substances. These differences permit classifying the abovementioned substances as different types of immunoglobulin molecules. The major difference between PRIGs and NAbs may include both the mechanisms of the above mentioned immunoglobulin molecules binding to antigens and their interaction affinity, as well as an absolutely different influence of some low-molecular substances on the efficiency of the interaction with antigens. Relying on the obtained data it can be assumed that, since PRIGs and NAbs have fundamental differences, they may perform not only similar but also different functions of the immune system.
Avidity of polyreactive immunoglobulins
S. A. Bobrovnik
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@bk.ru
An analysis of the mechanism of interaction between polyreactive immunoglobulins (PRIG) and antigen was conducted and it was shown that most of the traditional methods of antibody affinity evaluation are not applicable for PRIG affinity. The comparative assessment of the mouse and human PRIG avidity against ovalbumin and horse myoglobin and the avidity of specific monoclonal antibodies against ovalbumin have shown that the avidity of PRIG not only is much less than the avidity of monoclonal antibodies but even exceeds it.
Biological and immunochemical properties of polyreactive immunoglobulins
S. A. Bobrovnik, M. A. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@bk.ru
A previously unknown phenomenon of acquired polyreactivity of serum immunoglobulins, which were subject to the effect of concentrated solutions of chaotropic ions, such as KSCN (3.0-5.0 M), low/high pH (pH 2.2-3.0), or heating to 58-60 °C, was originally described by the authors in 1990. Eleven years after that, similar data were published by J. P. Bouvet et al.(2001), which confirmed completely our results concerning the influence of either chaotropic ions or drastic shift of pH on polyreactive properties of immunoglobulins. Our further investigations (1993, 1995, 1998) of polyreactive serum immunoglobulins (PRIG) properties have revealed that the mechanism of nonspecific interaction between PRIG and antigens much differs from the mechanism of interaction between specific antibodies and corresponding antigens. Later we have shown that the increase in PRIG reactivity could be induced in vivo (1999) and PRIG are one of serum components of human or animal sera. Then, it could be suggested that PRIG may perform certain biological functions. Studying PRIG’s effect on the phagocytosis of microbes or on the tumor growth (S. A. Bobrovnik et al., 1995, 1998) have revealed that PRIG may play a certain role in protecting the body from infections and probably may influence the development of various pathological processes. Recently we also found (S. A. Bobrovnik et al., 2014) that IgG PRIG content significantly increases in aged people. These data demonstrate that further investigations of PRIG’s immunochemical properties and study of their biological role in organism protection from various diseases is very important.
Interaction peculiarities of polyreactive immunoglobulins and various antigens
S. A. Bobrovnik, M. O. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukarine, Kyiv;
е-mail: s-bobrov@bk.ru
The influence of twin 20, lysozyme and protamine on the capability of polyreactive immunoglobulins (PRIG) to attach to various antigens was investigated. Twin 20 can inhibit the binding of PRIG to antigens on immunological plates but lysozyme and protamine can enhance it. As far as the mixture of the optimal concentrations of lysozyme and protamine cannot increase PRIG-antigen interaction in comparison to the optimal dose of protamine, we have concluded that the mechanism of their effect on PRIG binding is similar. Of special interest is the fact that twin 20 at optimal concentration of lysozyme or protamine does not decrease PRIG binding to various antigens but, on the contrary, increases PRIG-antigen interaction.