Identification of two binding sites in staphylococcal enterotoxin B that confer specificity for TCR Vβ gene products

John D. Hayball, John H. Robinson, Robyn E. O'hehlr, Adrienne Verhoef, Jonathan R. Lamb, Richard A. Lake

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25 Citations (Scopus)


The enterotoxlns produced by Staphytococcua af1reus are potent mitogens. They stimulate T cells in an oligocional fashion that Is dependent on the expression of particular variable region gene elements in the β-chaln of the TCR (Vβ). The fourth hypervarlable loop of the TCR β-chaln Is generally regarded as the site of contact for both viral and mlcroblal superantigens. Recently, residues 60 and 61 of staphylococcal enterotoxin B (SEB) have been highlighted as central to the interaction of this toxin with the TCR. We have, therefore, analysed a series of toxins with mutations at these positions to investigate how amlno add substitutions affect the ability of mutant toxins to stimulate both human and mouse T cells. Each of the variant toxins induced proliferation in a murine Vβ8.3 T cell clone, whereas a Vβ8.1 T cell clone only responded to native toxin. A panel of nine human T cell clones expressing six different Vβ elements, all of which responded to native SEB, was tested for reactivity to the variant toxins. Only one Vβ19.1+ T cell clone was found to be sensitive to substitution at positions 60 and 61 In a manner analogous to the murine Vβ8.1 T cell done. Seml-quantitatlve analysis of the TCR Vβ expression of human T cell lines expanded with native and mutant SEB revealed that none of the variant toxins could stimulate T cells that expressed Vβ19.1. Taken together, these results suggest that the interaction of mouse Vβ8.1 and human Vβ19.1 TCRs with SEB differs from other TCRs. Sequence comparisons of the different TCR Vβ chains indicated that residues in the second complementarity determining region (CDR2) interact with the 60-61 loop of SEB. Therefore, a minimum of two distinct binding modules confer specificity to the interaction of the TCR with SEB.

Original languageEnglish
Pages (from-to)199-211
Number of pages13
JournalInternational Immunology
Issue number2
Publication statusPublished - 1 Feb 1994
Externally publishedYes


  • Mutagenesis
  • Staphylococcal enterotoxin B
  • Superantigen
  • T cell receptor
  • T cell recognition

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