<i>Chlamydia trachomatis</i> cytotoxicity associated with complete and partial cytotoxin genes
Bibliographic record
Abstract
Chlamydia trachomatis is an obligate intracellular human bacterial pathogen that infects epithelial cells of the eye and genital tract. Infection can result in trachoma, the leading cause of preventable blindness worldwide, and sexually transmitted diseases. A common feature of infection is a chronic damaging inflammatory response for which the molecular pathogenesis is not understood. It has been proposed that chlamydiae have a cytotoxic activity that contributes to this pathology, but a toxin has not been identified. The C. trachomatis genome contains genes that encode proteins with significant homology to large clostridial cytotoxins. Here we show that C. trachomatis makes a replication-independent cytotoxic activity that produces morphological and cytoskeletal changes in epithelial cells that are indistinguishable from those mediated by clostridial toxin B. A mouse chlamydial strain that encodes a full-length cytotoxin caused pronounced cytotoxicity, as did a human strain that has a shorter ORF with homology to only the enzymatically active site of clostridial toxin B. Cytotoxin gene transcripts were detected in chlamydiae-infected cells, and a protein with the expected molecular mass was present in lysates of infected epithelial cells. The protein was present transiently in infected cells during the period of cytotoxicity. Together, these data provide compelling evidence for a chlamydial cytotoxin for epithelial cells and imply that the cytotoxin is present in the elementary body and delivered to host cells very early during infection. We hypothesize that the cytotoxin is a virulence factor that contributes to the pathogenesis of C. trachomatis diseases.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".