Sequence Variation in Group A Streptococcus Pili and Association of Pilus Backbone Types with Lancefield T Serotypes
F Falugi, C Zingaretti, V Pinto, M Mariani… - The Journal of …, 2008 - academic.oup.com
F Falugi, C Zingaretti, V Pinto, M Mariani, L Amodeo, AGO Manetti, S Capo, JM Musser…
The Journal of infectious diseases, 2008•academic.oup.comBackground. We previously reported that group A Streptococcus (GAS) pili are the T
antigens described by Rebecca Lancefield. We also showed that these pili, constituted by
backbone, ancillary 1, and ancillary 2 proteins, confer protection against GAS challenge in a
mouse model. Methods. We evaluated pilus distribution and conservation by sequencing the
subunits of 39 new GAS isolates and used immunoblot analysis and agglutination assays to
define the specificity of T sera to pilus subunits. Results. GAS pili are encoded by 9 different …
antigens described by Rebecca Lancefield. We also showed that these pili, constituted by
backbone, ancillary 1, and ancillary 2 proteins, confer protection against GAS challenge in a
mouse model. Methods. We evaluated pilus distribution and conservation by sequencing the
subunits of 39 new GAS isolates and used immunoblot analysis and agglutination assays to
define the specificity of T sera to pilus subunits. Results. GAS pili are encoded by 9 different …
Abstract
Background. We previously reported that group A Streptococcus (GAS) pili are the T antigens described by Rebecca Lancefield. We also showed that these pili, constituted by backbone, ancillary 1, and ancillary 2 proteins, confer protection against GAS challenge in a mouse model.
Methods. We evaluated pilus distribution and conservation by sequencing the subunits of 39 new GAS isolates and used immunoblot analysis and agglutination assays to define the specificity of T sera to pilus subunits.
Results. GAS pili are encoded by 9 different islands within which backbone protein, ancillary protein 1, and ancillary protein 2 cluster in 15, 16, and 5 variants, respectively. Immunoblot and agglutination assays revealed that T type is determined by the backbone variant. This observation enabled us to set up a simple polymerase chain reaction assay to define the T type of GAS isolates.
Conclusions. We propose the use of a tee gene sequence typing, analogous to the emm gene typing, as a valuable molecular tool that could substitute for the serological T classification of GAS strains. From our sequence analysis and from recent epidemiological data, we estimate that a vaccine comprising a combination of 12 backbone variants would protect against >90% of currently circulating strains.
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