Abstract: | The antigen-antibody equilibrium in the presence of a competitive agent of immunoglobulin nature, represented by anti-idiotypic antibodies, has been analyzed in the case of the immobilized antigen. As shown in this investigation, the amount of immunoglobulin bound with the carrier is determined both by the competition of anti-idiotypic antibodies for the active center of idiotype-carrying antibodies and by the binding of anti-idiotypic antibodies with the antigen-antibody complex. If idiotype-carrying and anti-idiotypic antibodies are represented by serum immunoglobulin of the same species, the titration of the competitive agent leads to obtaining a characteristic relationship between the amount of immunoglobulin bound with the insoluble phase and the amount of the competitive agent in the system passing through the maximum. The theoretical results have been confirmed on the experimental model and used for the identification of auto-antiidiotypic antibodies in patients' sera. |