Degradation of human secretory immunoglobulin A by Blastocystis

Parasitol Res. 2005 Nov;97(5):386-9. doi: 10.1007/s00436-005-1461-0. Epub 2005 Sep 7.


Microbial immunoglobulin A (IgA) proteases cleave human secretory IgA, promoting the mucosal adhesion of pathogens. To investigate if the enteric protozoan Blastocystis degrades human secretory IgA, cell lysate and conditioned medium from two species were exposed to immunoglobulin A. Secretory IgA was cleaved by both cell lysate and conditioned medium with mainly cysteine proteinase activity in B. hominis B isolate and aspartic proteinase activity in B. ratii WR1 isolate. These findings suggest that Blastocystis proteases may play a role in parasite survival in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aspartic Acid Endopeptidases / metabolism
  • Blastocystis / enzymology*
  • Blastocystis / growth & development
  • Blastocystis / pathogenicity
  • Blastocystis hominis / enzymology*
  • Blastocystis hominis / growth & development
  • Blastocystis hominis / pathogenicity
  • Culture Media, Conditioned / metabolism
  • Cysteine Endopeptidases / metabolism
  • Humans
  • Immunoglobulin A, Secretory / metabolism*
  • Rats


  • Culture Media, Conditioned
  • Immunoglobulin A, Secretory
  • Cysteine Endopeptidases
  • Aspartic Acid Endopeptidases