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An antiphagocytic factor associated with group E streptococcus.

R A Daynes·C H Armstrong
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Abstract

Group E streptococci (GES) grown in Tryptose phosphate broth (TPB) were highly susceptible to nonspecific phagocytosis by porcine leukocytes, whereas GES grown in serum-supplemented TPB (STPB) were resistant to nonspecific phagocytosis. It was concluded that serum supplementation induced the elaboration of an antiphagocytic factor (APF). The APF was distinct from the group-specific and type-specific polysaccharide antigens, and it was destroyed by trypsin. Electron photomicrographs revealed that GES grown in STPB possessed a fimbriated surface component similar to M protein-positive stains of group A streptococcus. The surface component was absent when GES were propagated in unfortified TPB. The APF was neutralized specifically by sera from swine immune to streptococcic lymphadenitis (SLS), a disease caused by GES. It was hypothesized that the APF was associated with the pathogenicity of GES and that it was involved in the induction of protective immunity to SLS.

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AnimalsBacteriological TechniquesCulture MediaImmune SeraImmunityLymphadenitisMicroscopy, ElectronPhagocytosisStreptococcusSwineSwine DiseasesTrypsinJournal Article

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R A Daynes, C H Armstrong. 1973. An antiphagocytic factor associated with group E streptococcus.. https://doi.org/10.1128/iai.7.2.298-304.1973

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