Expression, Immunogenicity and Variation of Iron-Regulated Surface Protein A from Bovine Isolates of Staphylococcus aureus

Neha Misra, Tyler F. Wines, Colton L. Knopp, Mark A. McGuire, Juliette K. Tinker

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Staphylococcus aureus iron-regulated surface protein A (IsdA) is a fibrinogen and fibronectin adhesin that also contributes to iron sequestration and resistance to innate immunity. IsdA is conserved in human isolates and has been investigated as a human vaccine candidate. Here we report the expression of isd A, the efficacy of anti-IsdA responses and the existence of IsdA sequence variants from bovine Staphylococcus. Clinical staphylococci were obtained from US dairy farms and assayed by PCR for the presence and expression of isd A. isd A-positive species from bovines included S. aureus , S. haemolyticus and S. chromogenes . Immunoassays on bovine milk and serum confirmed the induction and opsonophagocytic activity of anti-IsdA humoral responses. The variable region of isd A was sequenced and protein alignments predicted the presence of two main variants consistent with those from human S. aureus . Mouse antibodies against one IsdA variant reduced staphylococcal binding to fibronectin in vitro in an isotype-dependent manner. Purified IsdA variants bound distinctly to fibronectin and fibrinogen. Our findings demonstrate that variability within the C-terminus of this adhesin affects immune reactivity and binding specificity, but are consistent with the significance of IsdA in bovine disease and relevant for vaccine development.

Original languageAmerican English
JournalHistory Faculty Publications and Presentations
DOIs
StatePublished - 1 May 2017

Keywords

  • bovine
  • iron-regulated surface protein
  • staphylococcus aureus

EGS Disciplines

  • Biology

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