Techniques of modifying lipid antigens for synthesis of diagnostic and therapeutic preparations in rheumatology.

Abstract

The objective of the study is to enhance sorption capacity of diagnostic agents by using cardiolipin antigens for antiphospholipid syndrome in patients with systemic lupus erythematosus (SLE). A technique of emulsion polimerization was used. Having integrated antigen nanoobjects we developed immobilized magnetocontrollable antigen nanosystems and put them to an evaluation test. The nanosystems are polyacrylamide granules with a built in antigen. To obtain stable immobilized multi-use biopharmaceuticals with targeted properties (shape, particle diameter, pore size, density) we used a modified version of emulsion polymerization method using polyacrylamide carrier gel. This method permitted a greater sorptive capacity, preserving the antigen in maximum native state, and opened up the possibility of controllable modification of nanoobjects. Cardiolipin was used as the antigen in question. Following the method described above we performed sorption of anticardiolipin antibodies from blood plasma of SLE patients who showed clinical presentations of antiphospholipid syndrome. All SLE patoents with signs of antiphospholipid syndrome showed reliably higher levels of cardiolipin antibodies compared with SLE patients without antiphospholipid syndrome signs; the antibody level was 0.365 ± 0.026 and 0.075 ± 0.003 on average, correspondingly (p < 0.001). Blood serum from 10 apparently healthy individuals served as control. The level of cardiolipin antibodies was determined before and after sorption by indirect solid phase immunoenzyme method. In the eluate we estimated total protein by Lowry method. In vitro testing showed that the obtained antigen nanosystems based on immobilized cardiolipin could effectively remove cardiolipin antibodies from whole blood of SLE patients with clinical presentations of APS to achieve the values of healthy individuals (before sorption cardiolipin antibodies 0.328 ± 0.0289; after sorption 0.059 ± 0.0170; p<0,001; sorption capacity 8.00 ± 0.390 mg/ml). The method of emulsion polymerization with consideration to hydrophobic and hydrophilic properties of lipid molecules permits obtaining and modifying biomolecules with certain properties, in a controlled fashion.