Immunohistochemical and serological evidence for the role of streptococcal proteinase in acute post-streptococcal glomerulonephritis

Kidney Int. 1998 Sep;54(3):819-26. doi: 10.1046/j.1523-1755.1998.00052.x.

Abstract

Background: We have previously demonstrated the preferential secretion of streptococcal proteinase or streptococcal pyrogenic exotoxin B (SPEB) by nephritic strains of Group A streptococci isolated from the skin or throat of patients with acute poststreptococcal glomerulonephritis (APSGN).

Methods: To further explore the possible role of SPEB in APSGN, we performed ELISA studies to detect anti-SPEB antibodies in the sera of patients with APSGN, acute rheumatic fever (ARF), scarlet fever (SF) and normal children. Using ELISA, anti-SPEB titers on acute and convalescent APSGN sera were measured to determine immunity to APSGN. We also performed immunofluorescence studies on APSGN and non-APSGN kidney biopsies to probe for the presence and localization of SPEB.

Results: Our data show that anti-SPEB antibodies are present in APSGN sera and antibody titers are significantly higher than in ARF, SF and normal sera. Anti-SPEB titers tend to rise acutely and decrease with time but do not reach baseline after one year. When kidney biopsies were probed with rabbit anti-SPEB antibody, 12 of 18 (67%) of the APSGN cases were positive while only 4 of 25 (16%) of the non-APSGN cases were positive.

Conclusions: In summary, we were able to demonstrate unique reactivity to SPEB in human sera and kidney biopsies of APSGN suggesting a significant role of this toxin in the pathogenesis of acute post-streptococcal glomerulonephritis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bacterial Proteins*
  • Complement Activation
  • Cysteine Endopeptidases / physiology*
  • Exotoxins / physiology*
  • Fluorescent Antibody Technique
  • Glomerulonephritis / etiology*
  • Humans
  • Immunohistochemistry
  • Membrane Proteins*
  • Rabbits
  • Rheumatic Fever / etiology
  • Scarlet Fever / etiology
  • Streptococcal Infections / complications*
  • Streptococcus pyogenes*

Substances

  • Bacterial Proteins
  • Exotoxins
  • Membrane Proteins
  • SpeA protein, Streptococcus pyogenes
  • erythrogenic toxin
  • Cysteine Endopeptidases