Affinity electrophoresis with monoclonal antibodies
Affinity electrophoresis was applied to the study of binding of monoclonal antibodies (MoAb's) with their respective antigens. The MoAb's may be either mixed with the antigen in an application well or incorporated into the agarose gel. The first approach is more convenient for studying high affinity MoAb's, while MoAb's with low affinity might be more efficiently studied in the second system. Our conditions for affinity electrophoresis do not imply nor necessitate immobilization of either an antigen or MoAb and are most suitable for studies of MoAb's reacting with antigens of alpha mobility demonstrated in experiments with MoAb's against human alpha-fetoprotein (AFP). Both AFP-MoAb and AFP-MoAb-AFP complexes were observed during electrophoresis. The identity of these complexes was confirmed by their reaction both with polyclonal antibodies against mouse immunoglobulins and against human AFP. The molecular weight of complexes was determined by gel filtration. Affinity electrophoresis was less convenient for studies of MoAb's reacting with antigens of gamma mobility at pH 8.6. Nevertheless, MoAb's against carcinomembryonic antigen, human IgG and human IgA did bind with their respective antigens under the conditions of affinity electrophoresis. The binding of MoAb's with these antigens during affinity electrophoresis was confirmed by demonstration of mouse immunoglobulins in the precipitates formed by reaction of the studied antigens with polyclonal antibodies. Our results point out the suitability of affinity electrophoresis for studies of MoAb's.