Generation, characterization, and epitope mapping of neutralizing and protective monoclonal antibodies against staphylococcal enterotoxin B-induced lethal shock

Avanish K. Varshney, Xiaobo Wang, Emily Cook, Kaushik Dutta, Matthew D. Scharff, Michael J. Goger, Bettina C. Fries

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Abstract

T-cell stimulating activity of Staphylococcal enterotoxin B (SEB) is an important factor in the pathogenesis of certain staphylococcal diseases including SEB mediated shock. SEB is one of the most potent superantigens known and treatment of SEB induced shock remains a challenge. We generated and characterized murine monoclonal antibodies (mAbs) to SEB in mice. Wetested mAbs neutralize mitogenic effects of SEB in vitro and in vivo with T-cell proliferation assays and 2 murine models for SEB induced lethal shock (SEBILS). Epitope mapping suggests that all these mAbs recognize conformational epitopes that are destroyed by deleting the C terminus of the protein. Further site-directed mutagenesis identified potential residues involved in binding to SEB that differ between Methicillin resistant and sensitive Staphylococcus aureus strains. Only mAb 20B1 was effective as a monotherapy in treating SEBILS in HLA DR3 transgenic mice, which exhibit enhanced sensitivity to SEB. It is noteworthy that mAbs, 14G8 and 6D3 were not protective when given alone in theHLADR3 mice but their efficacy of protection could be greatly enhanced when mAbs were co-administered simultaneously. Our data suggest combinations of defined mAbs may constitute a better treatment strategy and provide a new insight for the development of passive immunotherapy.

Original languageEnglish (US)
Pages (from-to)9737-9747
Number of pages11
JournalJournal of Biological Chemistry
Volume286
Issue number11
DOIs
Publication statusPublished - Mar 18 2011

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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