P729 <i>Treponema pallidum-</i>platelet interactions and relevance to treponemal invasion
Bibliographic record
Abstract
Background Treponema pallidum ssp. pallidum (Tp), the causative agent of syphilis, is an invasive pathogen that interacts with host cells during infection. In the bloodstream Tp encounters platelets, which are sentinel cells that activate and release specific components to enhance immune cell targeting to the site of infection/inflammation. Tumor cells and invasive pathogenic bacteria can associate with platelets and recognize these same secreted components, to allow for enhanced spread via the bloodstream. We have previously established that Tp interacts with platelets: in this study we probe the potential for Tpto activate platelets and to recognize specific platelet secretions. Methods Viable Tp and platelets were co-incubated and platelet activation was compared relative to pre-activated (ACT) and resting (REST) platelets. Platelet activation was measured by assessing the median fluorescence intensity (MFI) of the platelet activation receptor CD41a via flow cytometry and fibrin clot formation (a downstream effect of platelet activation) via plate-based assays. A capillary tube chemotaxis assay quantified Tp migration towards specific secretions from activated platelets compared to inactive platelets. Results Tp co-incubated with platelets and ACT platelets expressed comparable levels of CD41a, with an almost 150% greater CD41a expression level compared to that seen with REST platelets (P = 0.0118). Tp co-incubated with platelets and ACT platelets produced similar levels of clotting, at a level that was significantly higher than for REST platelets (P = 0.0221). Tp migration towards the secretions of activated platelets was over 2-fold higher than migration towards inactive platelets (P = 0.0030). Conclusion Tp activates platelets and migrates towards the secretions of activated platelets. Prior investigations have established that platelet activation, and subsequent secretion, enhances the permeability of endothelial cells lining the bloodstream. Taken together, these findings suggest the treponeme-platelet interaction may promote Tp entry and exit from the bloodstream and aid in Tp spread throughout the body. Disclosure No significant relationships.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".