The exotoxins of certain strains of Staphylococcus aureus strains are able both to stimulate potent proliferation and induce anergy in T lymphocytes expressing the appropriate T cell Ag receptor Vβ gene elements. Although T cell activation by the S. aureus enterotoxins requires the presence of accessory cells bearing class II Ag of the MHC, unlike the peptide fragments of nominal Ag, they contact the external surfaces of both the class II MHC and TCR molecules. This paper investigates the immunologically active domains of S. aureus enterotoxin B (SEB) usintruncated fragments of rSEB expressed as a fusion protein with protein A. The results of the experiments reported here indicate that the minimal fragment of SEB able to stimulate and induce anergy in hemagglutinin-reactive human T cells expressing Vβ3.1 gene elements is located in the amino-terminal portion of the molecule within residues 1-138. Deletion of the first 30 amino acid residues renders rSEB unable to stimulate T cells expressing Vβ3.1, whereas polyclonal T cells still respond to this molecule. This implies that the stimulation of several TCR-Vβ families may be caused by the interaction with different regions of the toxin. The localization of immunologically active sites in the bacterial enterotoxins is needed to investigate both their biology and potential application as immunomodulatory agents.
|Number of pages||6|
|Journal||Journal of Immunology|
|Publication status||Published - 1 Jan 1992|