The Salmonella flagellar antigen g ... as a potential carrier of "foreign epitopes"
Masten, Barbara Jean
MetadataShow full item record
Salmonella flagella filaments are polymers of a protein termed, 'flagellin'. We are interested in expressing medically important epitopes at the site(s) of naturally occurring B-cell epitopes expressed by flagellin. To determine the molecular basis for expression of the epitopes by which the Salmonella phase-1 g... series flagellin antigens are distinguished, 17 members (S. adelaide [fliC9^, S. berta [fliC9% S. budapest [fliC9^, S. califomia [fUCd^rJt]^ S. chaco [fliCdrrt]^ S. danysz [fliCd"^, S. derby [fliC9f\, S. dublin [fliC9P], S. enteritidis [fliCQrrf], S. essen [fliCd'T^, S. jena [fiiCdn^, S. monschaui [fliC^^, S. montevideo [fliCd'T^^, S. moscow [fliC9Q], S. oranienberg [ftiC^, S. mstock [fliC9P% and S. senftenberg [fliC9S^) of this series were selected and their fliC (the stmctural gene for phase-1 flagellin) genes sequenced. Comparison of the flagellin amino acid sequences showed complete homology in the N-terminal (region I, II and III) and C-terminal (region VIII) segments of the proteins. Differences in amino acids were found throughout the central portion (regions IV, V, VI and VII) of the flagellins. No localized area substituted to specify subfactor epitopes could be identified, suggesting the subfactors of the g... series are conformational at the molecular level. The amino acids comprising each of the subfactor epitopes were not definable by sequence analysis. Results of epitope mapping, by two approaches, support the view that the g... series phase-1 flagellin B-ceil epitopes are conformational. Based upon amino acid comparison, the fliC gene of S. califomia, S. monschaui and S. oranienberg may be the gene of choice for substitution(s)since it may tolerate amino acid interchanges in region V better than the fliC gene of other members of the g... series. Hydrophobicity and surface exposure plots suggest three potential sites, two within region IV and one within region VI, for epitope substitution within the flagellin of any g... series member Phylogenetic analysis and comparative analysis shows S. california, S. monschaui and S. oranienberg to be the most diverse g... series serovars. A combination of spontaneous mutation, insertion and deletion most likely generated the antigenic polymorphism seen with salmonellar g... series flagellins.