Tag Archives: polyreactive immunoglobulins

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.