Degradation of human secretory immunoglobulin A by Blastocystis
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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.
KeywordsBlastocystis Immunoglobulin A Mucosal Proteinases Protozoa
This work was supported by generous grants from the National Medical Research Council (R-182-000-058-213) and the Faculty of Medicine, National University of Singapore. We thank Ms. Geok Choo Ng, Mr. Ramachandran for technical support and helpful discussions. Thanks are also due to Ms. Tan Mui Hong, Ms. Tan Li Li and Dr. Punam Dahiya, for their contributions. The present experiments were carried out in compliance with the laws and regulations of Singapore.
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