EPITOPE MAPPING OF BETA-LACTAM ANTIBIOTICS WITH THE USE OF MONOCLONAL-ANTIBODIES

In order to evaluate the antigenic contribution of different regions o f the penicillin molecule, monoclonal antibodies were raised against a moxicillin-protein conjugates and their specificities analysed in deta il. A random sample of the clones produced was analysed by a quantitat ive inhibition-ELISA, using, as inhibitors, monomeric conjugates of th e following antibiotics to butylamine (BA), amoxicillin (AX), ampicill in (AMP), benzylpenicillin (BP) and the nuclear part of these, 6-amino penicillanic acid (6-APA); and different parts of the following molecu les: N-(p-hydroxyphenyl)glycine (PHPG), N-phenylglycine (NPG), phenyla cetic acid (PA) and thiazolidine (TIAZ). The results showed that 92% o f the antibodies recognized an epitope in which the side chain was a m ajor constituent, although with variable contributions from other regi ons of the molecule. There was a high degree of crossreactivity with a minopenicillins, but low or absent crossreactivity with BP. None of th e antibodies recognized the thiazolidine ring or the conjugated nuclea r region of the penicillins. Finally, one antibody seemed to recognize , equally, all the different structures tested. The possible relevance of these results to penicillin allergy is discussed.