[Enzyme-immuno-assay in listeriosis: detection of antibody and antigen (author's transl)].

An enzyme-immuno-assay (EIA) was developed for the determination of antibodies to Listeria monocytogenes O- and H-antigens of serotypes 1 and 4b, which are predominant in the Federal Republic of Germany. The results correlated well with the tube agglutination but the titers in EIA were considerably higher. Thus one advantage of EIA was its sensitivity. In addition, the EIA offers the possibility to detect antibodies belonging to different immunoglobulin classes. The EIA is easy to perform and required smaller amounts of reagents than the tube agglutination. Since optical densitys is determined in the EIA, the data obtained in this system are less variable than the tube agglutination which is read by eye. The method proved also to be useful for the detection of Listeria-Antigen. Approximately 0.3 microgram/ml of H-antigen could still be detected in the EIA. Since the serological diagnosis of Listeria-infections is hampered by the cross-reactions to various other bacterial antigens the detection of Listeria-antigen by a sensitive immunological procedure could be of considerable value. This is especially the case when culture procedures are not promising, e.g. during or after antimicrobial chemotherapy.