Tag Archives: antibody-antigen interaction

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.

Advantages of two- or polyvalent binding of a receptor to the corresponding ligand in comparison to univalent binding

S. A. Bobrovnik, M. O. Demchenko, S. V. Komisarenko

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@bk.ru

The features of monovalent and bivalent binding­ of receptors (or antibodies) with a polyvalent ligand (or with an antigen) are considered. It is shown that the rigid connection of the binding­ sites of the receptor brings to high increase of binding affinity for the corresponding ligand, but only in case if its epitopes are fully complementary to both sites of the receptor binding. If not, then there is no advantage of the binding of bivalent receptor before univalent binding. If the binding sites of the receptor are connected by a flexible linker, then regardless of location of epitopes of the corresponding ligand there is the successful fastening of receptor and ligand. Exactly the connection by a flexible linker is used by Nature in most cases at constructing of polyvalent receptors.