ANTIGENIC LIPOPOLYSACCHARIDE COMPONENTS OF LEGIONELLA-PNEUMOPHILA RECOGNIZED BY MONOCLONAL-ANTIBODIES - POSSIBILITIES AND LIMITATIONS FOR DIVISION OF THE SPECIES INTO SEROGROUPS

Legionella pneumophila accounts for the majority of cases of Legionnai res' disease, By using rabbit antisera, the species has been divided i nto 14 numbered and 1 unnumbered serogroups, To recognize the antigeni c diversity of the lipopolysaccharide (LPS) responsible for this class ification, the Dresden Legionella LPS MAb panel, containing 98 monoclo nal antibodies (MAbs), was created, Each serogroup reference strain po ssesses at least one specific epitope not found on any other reference strain and therefore designated the serogroup specific epitope, When the appropriate MAbs were used for serotyping of 1,064 human and envir onmental isolates, 1,045 (98%) could be placed into the known serogrou ps. In most cases (97%), this was in agreement with the polyclonal typ ing, Of the 29 isolates that showed strong cross-reactivities with the rabbit antiserum panel, 11 could be typed easily by MAbs; for the rem aining 18, however, only serogroup-cross-reactive epitopes could be de termined, Below the serogroup level, monoclonal subtypes were found fo r 11 serogroups. Altogether, the Dresden Legionella LPS MAb panel was able to divide the 1,064 isolates tested into 64 phenons, indicating i ts usefulness for both serogrouping and subgrouping of L. pneumophila strains, In order to compare the identities of patient and environment al isolates, testing their reactivity with MAbs should be the first st ep, especially if large numbers of colonies are to be typed, Only in c ases of identical patterns are the more time consuming and expensive g enetic fingerprints necessary, Moreover, the MAbs can also be used for specific antigen detection in respiratory specimens on the serogroup or subgroup level.