title: The use of beta-lactamase in enzyme immunoassays for detection of microbial antigens.
abstract: The sensitivity and performance characteristics of enzyme immunoassays (EIA) depend to a great extent on the kinetics of the enzyme-substrate system used as indicator. We labeled a variety of polyclonal and monoclonal immunoglobulins with purified beta-lactamase and used them in sensitive EIA systems for the detection of a number of microbial antigens. Polyclonal antibodies to rotavirus, adenovirus, and Haemophilus influenzae type b polyribitol phosphate and monoclonal antibodies to dengue virus were labeled with beta-lactamase and used to provide sensitive direct EIA systems for the detection of the corresponding antigens. In addition, antibodies directed at animal immunoglobulins were labeled with beta-lactamase and used in indirect EIA for the detection of viral antigens with unlabeled anti-viral monoclonal and polyclonal antibodies. Similarly, avidin from Streptomyces was labeled with beta-lactamase and used to detect viral antigens tested for in an avidin-biotin format. Enzyme immunoassay systems with beta-lactamase-labeled antibodies were also used to detect rotaviral and adenoviral antigens in rectal swab specimens from children with acute gastroenteritis. The sensitivity of the beta-lactamase EIA compared favorably with that of analogous EIA systems using alkaline phosphatase or horseradish peroxidase. The results of a beta-lactamase EIA were easily determined by naked eye and a permanent record of the qualitative results obtained by the use of a standard office photocopier, obviating the need for an expensive colorimeter. Enzyme immunoassays using beta-lactamase have potential as practical assay systems for the detection of a wide range of microbial antigens using monoclonal and polyclonal antibodies.
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D000956:Antigens, Viral / Q000032:analysis*; D001360:Avidin; D001407:Bacillus / Q000201:enzymology; D006801:Humans; D007124:Immunoenzyme Techniques; D012401:Rotavirus / Q000276:immunology; D012400:Rotavirus Infections / Q000175:diagnosis; D001618:beta-Lactamases
chemical_list: D000942:Antigens, Bacterial; D000956:Antigens, Viral; D001360:Avidin; D001618:beta-Lactamases