Labelling of the anti-III-neurotubulin monoclonal antibody by 99mTc and its binding to responsible antigen.

BACKGROUND beta-III-neurotubulin is a characteristic degradation protein of cellular cytoskeleton of nervous tissues, which originates with disorders that lead to the loss of peripheral neurons or neurons of the central nervous system. For the diagnostics of neuropathic and neurodegenerative processes, beta-III-neurotubulin is therefore the goal structure, and radioactive labelled antibody TU-20 (99m)Tc could theoretically enable diagnostic application in vivo. MATERIAL AND METHODS In our case, were selected three ways of labelling monoclonal antibody IgG1-TU-20, which shows a high affinity towards beta-III-neurotubulin with (99m)Tc. The indirect labelling was ensured through the bifunctional chelator HYNIC, the direct labelling by electrolytic means, and the direct labelling of antibody TU-20 reduced by 2-mercaptoethanol. To observe each single feature, the appropriate chemical and biochemical control methods were used. Chemical purity was ensured by gel filtration and, together with chemical stability, it was checked by paper chromatography. To control the biological stability, SDS electrophoresis was used. The immunoreactivity was checked using ELISA-tests. RESULTS The results have shown that the optimal method for labelling the antibody TU-20 is indirect labelling through the bifunctional chelator HYNIC, and the least effective method of labelling the antibody TU-20 is reduced by 2-mercaptoethanol. DISCUSSION The results of labelling the monoclonal antibody towards antigen TU-20 with (99m)Tc confirmed that structure of the monoclonal antibody is destroyed by 2-mercaptoethanol, and in the case of electrolytic labelling, there are not enough binding places for radionuclide (99m)Tc on the monoclonal antibody.