Nachweis präzipitierender und nicht-präzipitierender Antikörper durch Überwanderungs-Elektrophorese

Abstract

This method makes use of the different electro-phoretic velocity of antigen and antibody at a given pH. The faster moving protein is applied to the paper strip behind the slower one. During the electrophoresis the protein which migrates with greater velocity will overtake the slower migrating protein (Uberwanderung). If an antigen-antibody reaction takes place between these proteins, complexes with different electrophoretic properties will be formed. Precipitating complexes do not move in the electric field; soluble complexes show velocities between that of the antigen and the antibody. In the present paper the "Uberwanderungs" -electrophoresis is used for quantitative separation of precipitating and non-precipitating antigen-antibody complexes. When 1 of the 2 proteins has been labelled by a radio-isotope (I131) it is possible to show its binding in precipitating and non-precipitating (soluble) complexes quantitatively by measurement of the radioactivity or radioautography. Antisera with the same quantity of precipitating antibodies show different quantities of soluble complexes. As only the precipitates are visible, antibody estimation by usual methods (immuno-electrophoresis, gel diffusion, ring test-precipitation) is incomplete. The antigen binding capacity of an antiserum shows maxima for soluble and precipitating complexes at a different Relation XAntibody y Antigen (R.A.A.). An antiserum is well characterized by (1) its antigen binding capacity (per unit antiserum or, better, per globulin molecule) and (2) the relation of soluble to precipitating complexes at a definite R.A.A. By a 2-dimensional method of "Uberwanderung"-electrophoresis it is possible to localize the antibody into a definite globulin without isolating the globulins.