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Proteaese activity of Blastocystis hominis subtype3 in symptomatic and asymptomatic patients
Dina Marie Abdel-Hameed1, Omayma Mohamed Hassanin
1Department of Parasitology, Faculty of Medicine, Ain Shams University, 13 B Kornesh El Neel, Aghkhan, Shobra, Cairo, Egypt. emara7777@yahoo.com
Abstract:
Despite accumulating evidence indicating that Blastocystis hominis is pathogenic and that cysteine proteases are involved in its pathogenesis, few researches discussed the protease activity of B. hominis genetic subtypes. Therefore, the present study aims to identify the underlying pathogenic role of the proteases of B. hominis subtype 3 at different molecular weights in correlation to gastrointestinal symptoms. Of 65 patients with various clinical presentations referred to our laboratory for stool examination, 26 (40%) were B. hominis positive by stool culture. Of 26 (group I) B. hominis patients, 18 (69.2%) were symptomatic (group IA) and 8(30.8%) were asymptomatic (group IB). Of 25 normal control group (group II), 5 (20%) were B. hominis positive. Subtype 3 was the only genotype recovered by polymerase chain reaction. Of 26 patients in group I, 19 (73.1%) were immunocompetent and 7 (26.9%) were immunocompromised. Protease activities of B. hominis subtype 3 were recognized at 32-kDa (46.2%), 39-kDa (7.7%), 120-kDa (38.5%), 140-kDa (11.5%), and 215-kDa (19.2%) bands in gelatin sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Proteases were recognized in 17 (94.4%) out of 18 symptomatic Blastocystis patients versus 2 (25.0%) out of 8 asymptomatic patients. Proteases at 32 kDa were reported in 61.1% of symptomatic versus 12.5% of asymptomatic patients. It was concluded that proteases of B. hominis genetic subtype 3, particularly those at 32 kDa, could be considered a virulence factor that is responsible for protein degradation and have a possible pathogenic role in host immune evasion.
Insights
Blastocystis hominis subtype 3 proteases, especially at 32-kDa, are linked to gastrointestinal symptoms and may be a virulence factor. This study highlights their role in pathogenesis and immune evasion.
Area of Science:
- Medical Parasitology
- Molecular Pathogenesis
- Gastroenterology
Background:
- Blastocystis hominis is increasingly recognized as a pathogen.
- Cysteine proteases are implicated in Blastocystis hominis pathogenesis.
- Limited research exists on the protease activity of specific B. hominis genetic subtypes.
Purpose of the Study:
- To investigate the pathogenic role of Blastocystis hominis subtype 3 proteases.
- To correlate protease activity at different molecular weights with gastrointestinal symptoms.
- To identify potential virulence factors in B. hominis subtype 3.
Main Methods:
- Stool culture and polymerase chain reaction (PCR) for B. hominis detection and subtyping.
- Gelatin sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to identify protease activity.
- Comparison of protease profiles between symptomatic and asymptomatic patients.
Main Results:
- Blastocystis hominis subtype 3 was the only genotype detected.
- Protease activities were identified at various molecular weights (32, 39, 120, 140, 215 kDa).
- Proteases, particularly the 32-kDa band, were significantly more prevalent in symptomatic patients (61.1%) compared to asymptomatic ones (12.5%).
Conclusions:
- Proteases of Blastocystis hominis subtype 3, especially the 32-kDa enzyme, are potential virulence factors.
- These proteases likely contribute to protein degradation and host immune evasion.
- The study suggests a pathogenic role for B. hominis subtype 3 proteases in gastrointestinal disease.
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