Immunological activities of IgG antibody on pre-coated Fc receptor surfaces

The immunological activities of an IgG antibody bound on Fc receptors, such as protein A and protein G, pre-coated on a glassy carbon electrode surface have been studied. In order to discriminate the effects of molecular orientation and the conformation retention of the antibody on a protein sublayer, the activities of the antibody chemically coupled to both bare and bovine serum albumin (BSA)-pre-coated electrode surfaces were also determined. A non-competitive sandwich electrochemical enzyme immunoassay was applied to determine the relative surface activities. It was shown that the general antigen binding ability of the antibody on the protein A surface was the highest among the four immobilisation techniques used, whereas the activity on the BSA-modified surface was the lowest. Although the antibody coupled on the protein G surface also offers a certain degree of orientation, its general activity showed no large increase compared to that of antibody bound to the bare electrode surface, since the concentration of the antibody on its surface was lower than that of the bare surface.