Monoclonal antibodies to TEM-1 plasmid-mediated beta-lactamase

At least 28 plasmid-mediated beta-lactamases have been described in gram-negative bacteria. To assess the relationship among these enzymes, we produced and characterized 28 murine monoclonal antibodies to the TEM-1 plasmid-mediated beta-lactamase. Radial immunodiffusion identified 3 monoclonal antibodies as immunoglobulin M (IgM), 18 as subclass IgG1, 2 as IgG2a, and 5 as IgG2b. Using a newly described enzyme immunoassay, cross-reactivity of 16 of these monoclonal antibodies was tested against 24 plasmid-determined beta-lactamases. The 16 monoclonal antibodies cross-reacted with TEM-2 and TLE-1 and, to a certain extent, SHV-1. Different levels of cross-reactivity were also observed with OXA-3 (11 of 16), OXA-7 (8 of 16), OXA-1 (2 of 16), OXA-6 (2 of 16), and AER-1 (2 of 16). Six monoclonal antibodies demonstrated partial neutralization of beta-lactamase activity. This study suggests that common epitopes are shared by nine biochemically distinct plasmid-mediated beta-lactamases. On the basis of cross-reactivities with these monoclonal antibodies, we identified four epitopes on TEM-1, TEM-2, TLE-1, and SHV-1 beta-lactamases.