Induction and characterization of multianalyte antibodies against penicillins in egg yolk

Antibodies against penicillins were induced in eggs of laying hens after immunization with 6-aminopenicillanic acid (6-APA) coupled to key-hole limpet hemocyanin (KLH). Development of the antibody titer was monitored by an indirect enzyme-linked immunosorbent assay (ELISA), with 6-APA coupled to ovalbumin as antigen for coating microtiter plates. Different characteristics (time course, affinity) of the immune reaction were observed by testing eggs of individual hens. Titer values varied between 150 and 2000. Antibodies were isolated by polyethylene glycol precipitation and affinity chromatography, using a hapten sorbent with 6-APA as ligand. Glycine buffer, pH 3.0, was used to elute the immunoglobulins. Antibody specificity was determined in a competitive ELISA with 7 penicillins and the cephalosporin cephalexin as competitors. Cross reactivities for the penicillins were between 100 and 290% (6-APA = 100%). Cephalexin cross reacted only marginally (3%).