title: [A study on the pathogenesis of Streptococcus mitis exotoxin].
abstract: OBJECTIVE
  To study the isolation, purification and pathogenesis of Streptococcus mitis pyrogenic exotoxin causing toxic shock syndrome.
  
  
  METHODS
  Streptococcus mitis isolated from patients' throat were shaking cultivated. After being centrifuged, the supernatant fluid of the culture was precipitated with 20%, 40%, 60%, 80% (NH(4))(2)SO(4) respectively and the fast protein liquid chromatography(FPLC) was used for the final step of purification. Rabbits receiving subcutaneous injection with respective purified proteins were monitored daily for fever. The ability of the purified proteins to enhance the susceptibility of the rabbits to lethal Escherichia coli endotoxin shock is recorded, when the endotoxin was injected intravenously 4 hours after administration of 10 microg Streptococcus mitis exotoxin.
  
  
  RESULTS
  Only the protein precipitated by 20% (NH(4))(2)SO(4) (molecular weight is 34,000) from culture supernatant fluid was pyrogenic for rabbits (average temperature increase near 1 degrees C), and it can also cause the proliferation of rabbit splenocytes (mitogenicity). All the animals receiving subcutaneous injection of exotoxin containing purified proteins precipitated with higher concentrations of (NH(4))(2)SO(4) died within 16 approximately 29 hours after intravenous injection of the Escherichia coli endotoxin, demonstrating the enhanced susceptibility of the animals to lethal endotoxin shock. The control rabbits displayed none of these effects.
  
  
  CONCLUSIONS
  Streptococcus mitis exotoxin is a novel streptococcal pyrogenic exotoxin.
authors.affiliation: Huashan Hospital, Shanghai Medical University, Shanghai 200040, China.
authors.forename: H
authors.initials: H
authors.lastname: Lu
authors.forename: X
authors.initials: X
authors.lastname: Weng
authors.forename: Y
authors.initials: Y
authors.lastname: Yin
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Jiang
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Qian
authors.forename: B
authors.initials: B
authors.lastname: Zhu
authors.forename: B
authors.initials: B
authors.lastname: Peng
authors.forename: Z
authors.initials: Z
authors.lastname: Gong
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000302:isolation & purification / Q000633:toxicity*; D005098:Exotoxins / Q000302:isolation & purification / Q000633:toxicity*; D006801:Humans; D011817:Rabbits; D012772:Shock, Septic / Q000382:microbiology*; D034361:Streptococcus mitis / Q000302:isolation & purification / Q000472:pathogenicity*
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins