The discovered earlier phenomenon of the enhancment of polyreactive immunoglobulines (PrIGs) [1,2], that PRIGs binding to antigens strongly depended (resulted in increase or decrease) on the properties of the incubation medium. For example, the presence in the incubation media either Tween 20 or 1-anilino-8-naphthalenesulfonate significantly inhibi ted PRIGs binding to antigens. In contrast, several proteins, which had positive charge at neutral pH in aqueous solutions, were able to increase PRIGs reactivity and stimulate PRIGs-antigen interac tion. Some of such proteins were salmon caviar protamine and hen egg lysozyme. As we have found, the protamine much stronger increased PRIGs interaction with antigens than lysozyme [1,2]. In addition, it was determined, that albeit Tween 20 weakened the PRIGs interaction with antigens. We could observe the opposite effect in the presence of protaminetogether with protamine Tween 20 increased the PRIGs binding to antigens more efficiently, than the same concentration of protamine in the absence of Tween 20.Since more detailed study of this effect could shed light on the details of the mechanism of PRIGs interaction with antigens, we decided to investigate how protamine optimal dozes influenced the rate constant of PRIGs binding to the immobilized on the plate antigen in the presence of Tween 20, as well as on the affinity of PRIGs binding to the antigen in solution. The results of this investigation are described in this paper.
materials and methodsAntigen, PrIGs, and eLISA. We used bovine serum albumin (BSA) from Sigma, USA as an antigen. Protamine from the salmon caviar was from Sigma, USA. Mice normal serum was used as a pool of PRIGs. In our preliminary investigations it was shown that this serum had high level of PRIGs activi ty (not published).The quantity of immunoglobulins bound to the absorbed antigen on the plate in different conditions was determined by enzyme-linked immunosor bent assay (ELISA). For this purpose, the plates with PRIGs bound to immobilized antigen were incubated with goat anti-mouse IgG antibodies conjugated with peroxidase (Sigma, USA) during 60 min at 4 ºС. The unbound conjugates were carefully washed away, and peroxidase substrate -the solution of orthophenilen diamine (1 mg/ml) in 0.01 M phosphate buffer, pH 5.0 and 0.003% Н 2 О 2 solution were added .