Cysteine proteases: potential serodiagnostic reagents for human Schistosomiasis and Fasciolosis
Bibliographic record
Abstract
Schistosomiasis and fasciolosis are parasitic diseases that affect a great number of people, particularly in developing countries, and cause huge global morbidity. Diagnosis is essential for control, treatment and prognosis of the diseases and yet a simple, cheap, sensitive and specific assay is not readily available for either of them. In the current study, cathepsin B (SmCB) and cathepsin L1 (FhCL1) were investigated as potential diagnostic reagents to detect schistosomiasis and fasciolosis, respectively, in humans. The genes encoding SmCB and FhCL1 were expressed Pichia pastoris and the proteins isolated to homogeneity by affinity chromatography. The SmCB ELISA was optimized for antigen concentration, primary antibody dilution and secondary antibody dilution using a pool of sera obtained from patients that were coprologically-positive or negative for schistosomiasis. A clear distinctive was achieved between these two sera pools. However, when employed to screen a panel of patients from Senegal the test failed to provide satisfactory discrimination between schistosoma-infected and schistosoma-negative individuals. The FhCL1 ELISA was optimized using sera from Fasciola-infected individuals from Cuba, and samples from Cuban and Canadian non-infected patients. We determined the optimal dilution for the primary antibody and also assessed/compared the performance of anti-total IgG, IgG4, IgG1 and IgG2 secondary conjugated antibodies. Total IgG provided the best discrimination between Fasciola- infected and non-Fasciola infected individuals with a 99.99% sensitivity and specificity. Furthermore, by screening sera obtained from patients infected with various worm and protozoan diseases we showed that the FhCL1 ELISA does not cross-react with other diseases commonly found in similar geographical regions as fasciolosis. In conclusion, diagnosis of human schistosomiasis still remains uncertain and more studies need to be performed to improve our diagnostic test using SmCB. On the other hand, we have developed a simple, sensitive, specific and accurate test to detected human fasciolosis by using FhCL1, a major protease released by the parasite. The P. pastoris expression system allowed us to obtain up to 80 mg of FhCL1 enzyme per 4 L culture. Therefore, we not only have developed a standardized test that showed high specificity and sensitivity but we also have the methodology to obtain sufficent quantities of antigen needed future mass screening of human fasciolosis in affected regions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".