title: Induction of myocarditis in rabbits injected with group A streptococci.
abstract: OBJECTIVE
  We have earlier proposed that group A streptococcal (GAS) immunoglobulin binding surface proteins (IgGBPs) might trigger anti-IgG production and immune complex formation leading to glomerulonephritis. In the present study, cardiac tissue material from rabbits injected with heat-killed GAS was investigated.
  
  
  METHODS
  Rabbits were injected intravenously with 10(9) colony forming units of streptococci three times weekly for 8 wk. Cardiac tissue samples were obtained at different times and deposition of IgG, C3, TNF-alpha and IL-6 was studied.
  
  
  RESULTS
  After 8 or more weeks of intravenous (iv) injections, minimal changes were seen in animals receiving an IgG non-binding GAS strain, type T27, whereas in those animals receiving either of two IgG binding GAS strains, types M1 or M22, strong inflammatory and degenerative myocardial changes accompanied by deposition of IgG and C3 were noted. Furthermore, on injecting rabbits with defined mutants of a type M22 strain, the development of myocardial tissue damage proved to be dependent on the presence streptococcal IgGBPs.
  
  
  CONCLUSIONS
  The present data supported a role of streptococcal IgGBPs in the induction of myocardial tissue injury by GAS.
authors.affiliation: Institute of Experimental Medicine, Academy of the Medical Sciences, St.Petersburg, Russia.
authors.forename: L A
authors.initials: LA
authors.lastname: Burova
authors.forename: V A
authors.initials: VA
authors.lastname: Nagornev
authors.forename: P V
authors.initials: PV
authors.lastname: Pigarevsky
authors.forename: M M
authors.initials: MM
authors.lastname: Gladilina
authors.forename: I V
authors.initials: IV
authors.lastname: Molchanova
authors.forename: E A
authors.initials: EA
authors.lastname: Gavrilova
authors.forename: A A
authors.initials: AA
authors.lastname: Totolian
authors.forename: A
authors.initials: A
authors.lastname: Thern
authors.forename: C
authors.initials: C
authors.lastname: Schalén
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009205:Myocarditis / Q000382:microbiology*; D011817:Rabbits; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000472:pathogenicity*