title: A neutralizing epitope of the superantigen SEA has agonist activity on T cells.
abstract: We have previously shown that sequence 121-149 of the staphylococcal enterotoxin superantigen SEA plays an important role in superantigen function. A synthetic peptide of this region, SEA(121-149), blocks SEA binding to class II MHC molecules and induces interleukin-1 and tumor necrosis factor production in monocytes. In this study, we further emphasize the structural and functional significance of this region of SEA by showing that the SEA(121-149) peptide induces T cell proliferation in a manner similar to that of SEA. SEA(121-149) reacted with antibodies produced to SEA, and the SEA(121-149) specific antibodies neutralized SEA mitogenic activity. A tetrameric form of SEA(121-149) showed increased binding to antibodies and enhanced T cell activation, consistent with the greater avidity associated with increased valency. These data suggest that the internal domain of SEA corresponding to residues 121-149 plays an important role in superantigen activity.
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Gainesville 32611, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Hobeika
authors.forename: H M
authors.initials: HM
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D004768:Enterotoxins / Q000737:chemistry / Q000494:pharmacology*; D000939:Epitopes / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D013154:Spleen / Q000276:immunology; D018089:Superantigens / Q000737:chemistry / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
chemical_list: D000906:Antibodies; D004768:Enterotoxins; D000939:Epitopes; D010446:Peptide Fragments; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal