Enzyme-linked immunosorbent assay for detection of antibodies to the unmodified beta-lactam ring

Dose- and pH- dependent carbodiimide-mediated coupling of Penicillin-G to polystyrene microtiter-plates that leaves the beta-lactam ring unchanged is described. A new ELISA method was developed using Penicillin-G coated plates. The binding of 3 different monoclonal antibodies as well as human IgG antibodies of the IgG₁ and IgG₃ subclasses is demonstrated, whereas IgG₂, IgG₄ and IgE antibodies did not bind. Thus, covalently coupled Penicillin-G can be used to study the immune-response to the unchanged β-lactam ring in patients receiving penicillin therapy. The new method is complementary to hitherto described techniques, which generally only allow detection of antibodies binding to penicilloyl-groups.