title: Inhibition of emetic and superantigenic activities of staphylococcal enterotoxin A by synthetic peptides.
abstract: Staphylococcus aureus is a major human pathogen producing different types of toxins. Enterotoxin A (SEA) is the most common type among clinical and food-related strains. The aim of the present study was to estimate functional regions of SEA that are responsible for emetic and superantigenic activities using synthetic peptides. A series of 13 synthetic peptides corresponding to specific regions of SEA were synthesized, and the effect of these peptides on superantigenic activity of SEA including interferon γ (IFN-γ) production in mouse spleen cells, SEA-induced lethal shock in mice, spleen cell proliferation in house musk shrew, and emetic activity in shrews were assessed. Pre-treatment of spleen cells with synthetic peptides corresponding to the regions 21-40, 35-50, 81-100, or 161-180 of SEA significantly inhibited SEA-induced IFN-γ production and cell proliferation. These peptides also inhibited SEA-induced lethal shock. Interestingly, peptides corresponding to regions 21-40, 35-50 and 81-100 significantly inhibited SEA-induced emesis in house musk shrews, but region 161-180 did not. These findings indicated that regions 21-50 and 81-100 of SEA are important for both superantigenic and emetic activities of SEA molecule while region 161-180 is involved in superantigenic activity but not emetic activity of SEA. These regions could be important targets for therapeutic intervention against SEA exposure.
authors.affiliation: Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
authors.forename: Edward K
authors.initials: EK
authors.lastname: Maina
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Hu
authors.forename: Krisana
authors.initials: K
authors.lastname: Asano
authors.forename: Akio
authors.initials: A
authors.lastname: Nakane
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004639:Emetics / Q000494:pharmacology*; D004768:Enterotoxins / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D007371:Interferon-gamma / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000494:pharmacology*; D012772:Shock, Septic / Q000188:drug therapy; D012788:Shrews; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D013211:Staphylococcus aureus / Q000276:immunology; D018089:Superantigens / Q000494:pharmacology*; D014839:Vomiting / Q000139:chemically induced / Q000188:drug therapy
chemical_list: D004639:Emetics; D004768:Enterotoxins; D010446:Peptide Fragments; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal; D007371:Interferon-gamma