Herpes Simplex Virus Infection of Endothelial Cells Is Enhanced by Thrombin.
Bibliographic record
Abstract
Abstract Herpes simplex virus type 1 (HSV1) and type 2 (HSV2) are highly prevalent and form life-long infections. While acute effects are not often critical, chronic infection has been linked to vascular disease. To better understand the underlying basis for the clinical correlations, our lab has demonstrated that HSV can initiate and sustain clot formation directly on the virus surface, bypassing the normal cellular requirements. This is facilitated by anionic phospholipid and tissue factor on HSV1 and HSV2, and the participation of at least HSV1- encoded glycoprotein C (gC) in factor VIIa-dependent factor X (FX) activation, emulating tissue factor. The evolution of the HSV surface as a procoagulant agent suggests that generation of thrombin is advantageous to the viral lifecycle. The current study therefore examines the hypothesis that thrombin enhances infection. Several purified HSV1 strains were evaluated, including the wild-type lab strain, MacIntyre, and the clinical isolate, NS. These viruses were compared to gC-deficient HSV1, ns-1, and the gC-restored strain, rns. As an example of HSV2, strain G, was also examined. ns-1 has been shown previously to generate less FXa per particle than the gC-containing viruses. To restrict in situ thrombin production, human umbilical vein endothelial cells were inoculated in serum-free culture media. Consistent with our hypothesis, standard plaque-forming assays revealed that co-incubation of the virus and cells with purified thrombin enhanced infection by up to 400%. The observed half-maximal concentration was approximately 20 nM thrombin for all viruses studied. As a demonstration of specificity, hirudin attenuated the effects of purified thrombin. The involvement of the protease activated receptor 1 (PAR1) in this mechanism was shown using the functional signaling analogue, thrombin receptor activating peptide (TRAP). In the absence of serum, TRAP resulted in increased infection comparable to that of purified thrombin. Approximately half the effect of TRAP was observed at 10uM, while a PAR4-activating peptide had no effect. Enabling the production of thrombin during the infection process, plaque-forming assays were also conducted with serum in the cell culture media. The presence of serum enhanced infectivity by as much as 20-fold. At a constant hirudin concentration of 5 U/ml, infection was attenuated by approximately 50% for the gC-deficient strain, ns-1, whereas the other viruses were only marginally or insignificantly affected, supporting a role for thrombin generation in situ and the participation of gC. Collectively, these data show that thrombin production by HSV enhances infection through a mechanism involving PAR1-mediated cell modulation.
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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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".