Development of monoclonal antibodies against Ureaplasma urealyticum serotypes and their use for serotyping clinical isolates

Monoclonal antibodies (MAbs) against Ureaplasma urealyticum serotype 2, 5, 7, 8, 10, 11, 12, and 13 reference strains were developed. The reactivities of these MAbs with the 14 serotype reference strains was verified by colon y immunofluorescence assay and Western blot assay. MAbs against serotypes 2 , 7, 10, 11, and 12 were serotype specific, whereas MAbs against serotypes 5, 8, and 13 showed cross-reactivity. All MAbs against serotype 5 were cros s-reactive with serotype 2, and one showed, in addition, cross-reactivity t o serotypes 9 and 10, Mutual cross-reactivities were observed between MAbs against serotypes 8 and 13, The usefulness of the MAbs for the serotyping o f U. urealyticum strains was evaluated by serotyping 21 selected clinical i solates. A complete set of MAbs (the newly developed MAbs and the previousl y described MAbs against serotypes 1, 3, 4, 6, 9, and 14) as well as a comp lete set of polyclonal antibodies (PAbs), PAbs 1 to 14, were used. MAbs wer e able to identify 18 of 21 isolates including 2 isolates with mixed seroty pes, Polyreactivity, which occurred with 19 of the 21 isolates with PAbs, w as not observed by the use of MAbs. MAbs seem to be a more valuable tool th an PAbs for serotyping and could help in investigating a possible link betw een the expression or variability of the serotype-specific antigens and pat hogenicity.