Antigenic diversity in flagellar epitopes among Bacillus piliformis isolates.

Monoclonal antibodies (MAbs) were developed to Bacillus piliformis isolate-specific flagellar epitopes and used to group B. piliformis isolates on the basis of epitope expression. BALB/c mice immunised with flagella purified from various B. piliformis isolates served as the source of immune spleen cells for fusion with SP2/0Ag14 myeloma cells. Evaluation of hybridoma culture medium by ELISA against various bacterial species and B. piliformis isolates indicated that 482 of 2127 hybridomas secreted antibodies specific for B. piliformis. Specificity of MAbs for flagellar epitopes was demonstrated by indirect fluorescent antibody assays and Western blot analyses. Probing of 10 B. piliformis isolates with MAbs indicated that four B. piliformis isolates each possessed a distinct and isolate-specific flagellar epitope; five other isolates shared a common flagellar epitope. One isolate did not react with any of the MAbs specific for flagellar epitopes. Thus, B. piliformis isolates could be grouped into six antigenically distinct groups based upon flagellar epitope expression. Additionally, a MAb reactive with a cell-associated component recognised all but one isolate. This serological grouping of B. piliformis isolates agrees with the grouping of isolates based upon genetic and physiological characteristics, and supports the assertion that there are different strains among B. piliformis isolates.