Blastocystis hominis: evidence for caspase-3-like activity in cells undergoing programmed cell death.
We have shown previously that the human intestinal protozoan, Blastocystis hominis, undergoes apoptosis-like programmed cell death (PCD) when exposed to a cytotoxic monoclonal antibody (mAb), 1D5. In the present study, ELISA and immunoblot assays employing chicken anti-CPP32 antibody suggest that caspase-3-like antigens exist in B. hominis. Using colorimetric and flow cytometric assays for caspase-3 activity, we also observed an increase in activity between 1 h and 6 h after exposure to mAb 1D5, with greatest activity at 6 h. These findings suggest that caspase-3-like proteases play an important role in B. hominis undergoing PCD, similar to the phenomenon in higher eukaryotic organisms.
Nasirudeen
A M
AM
Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore.
Singh
M
M
Yap
E H
EH
Tan
K S
KS
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000913:Antibodies, Protozoan / Q000494:pharmacology; D000953:Antigens, Protozoan / Q000276:immunology; D017209:Apoptosis; D016845:Blastocystis hominis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000032:analysis / Q000378:metabolism*; D016054:DNA, Protozoan / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D011003:Ploidies
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases