Characterization of two novel pyrogenic toxin superantigens made by an acute rheumatic fever clone of Streptococcus pyogenes associated with multiple disease outbreaks.

ABSTRACT: The pathogenesis of acute rheumatic fever (ARF) is poorly understood. We identified two contiguous bacteriophage genes, designated speL and speM, encoding novel inferred superantigens in the genome sequence of an ARF strain of serotype M18 group A streptococcus (GAS). speL and speM were located at the same genomic site in 33 serotype M18 isolates, and no nucleotide sequence diversity was observed in the 33 strains analyzed. Furthermore, the genes were absent in 13 non-M18 strains tested. These data indicate a recent acquisition event by a distinct clone of serotype M18 GAS. speL and speM were transcribed in vitro and upregulated in the exponential phase of growth. Purified SpeL and SpeM were pyrogenic and mitogenic for rabbit splenocytes and human peripheral blood mononuclear cells in pico

SUBMITTER: Smoot LM 

PROVIDER: S-EPMC133074 | biostudies-literature | 2002 Dec

REPOSITORIES: biostudies-literature