title: Interaction of staphylococcal toxic shock syndrome toxin-1 and enterotoxin A on T cell proliferation and TNFα secretion in human blood mononuclear cells.
abstract: BACKGROUND
  The majority of menstrual toxic shock syndrome (MTSS) cases are caused by a single clone of Staphylococcus aureus that produces both toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin A (SEA).
  
  
  OBJECTIVE
  To determine whether the two superantigens interact to cause an enhancement of biological activity in human peripheral blood mononuclear cells (PBMCs).
  
  
  METHODS
  PBMCs from nine healthy donors were stimulated with TSST-1 or SEA, either alone or in combination at their minimum effective concentrations.
  
  
  METHODS
  In vitro study.
  
  
  METHODS
  Human PBMCs were stimulated in vitro with TSST-1 (1 pg/mL), SEA (0.1 pg/mL) or combination for 20 to 72 h. Mitogenic response was determined by [(3)H]-thymidine incorporation. PBMC culture supernatants were assayed for the presence of tumour necrosis factor-alpha (TNFα), interleukin (IL)-1β and IL-6 by ELISA.
  
  
  RESULTS
  The combination of TSST-1 and SEA induced significantly greater mitogenesis in human PBMCs compared with either toxin alone (P<0.05, paired Student's t test, two-tailed). Similarly, the production of TNFα in culture supernatants was significantly greater in the combination of TSST-1 and SEA compared with either TSST-1 or SEA alone (P<0.05). In contrast, no enhancement in the levels IL-1 or IL-6 was observed.
  
  
  CONCLUSIONS
  These data suggest that the co-production of TSST-1 and SEA by S aureus may provide some biological advantage to the organism throughs an enhanced effect of these superantigens on T cell activation and TNF secretion.
authors.affiliation: Division of Infectious Diseases, Departments of Medicine.
authors.forename: M L
authors.initials: ML
authors.lastname: De Boer
authors.forename: W W
authors.initials: WW
authors.lastname: Kum
authors.forename: A W
authors.initials: AW
authors.lastname: Chow