Contribution of <i>Burkholderia cenocepacia</i> Flagella to Infectivity and Inflammation
Bibliographic record
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that can cause severe lung infections in cystic fibrosis patients. To understand the contribution of B. cenocepacia flagella to infection, a strain mutated in the major flagellin subunit, fliCII, was constructed in B. cenocepacia K56-2 and tested in a murine agar bead model of lung infection. C57/BL6 mice infected with approximately 10(8) wild-type K56-2 bacteria exhibited 40% mortality after 3 days, whereas no mortality was noted in mice infected with the fliCII mutant. Among the mice surviving the infection with either strain, there was no significant difference in the bacterial loads in the lungs and spleen, bacteremia, weight loss, or infiltration of immune effector cells at 3 days postinfection. Similar results were observed at 24 h, prior to expression of the lethality phenotype. KC, a murine interleukin-8 (IL-8) homolog, was elevated in both the bronchoalveolar lavage fluid and serum of mice infected with the wild type compared to the fliCII mutant at 24 h, suggesting that flagella stimulated host cells. To demonstrate that flagella contributed to these responses, the interaction between B. cenocepacia and Toll-like receptor 5 (TLR5) was investigated. Infection of HEK293 cells with heat-killed wild-type K56-2, but not infection with the fliCII mutant, resulted in both NF-kappaB activation and IL-8 secretion that was dependent upon expression of TLR5. Together, these results demonstrate that B. cenocepacia flagella contribute to virulence in an in vivo infection model, and that induction of host immune responses through interaction with TLR5 may contribute to its overall pathogenic potential.
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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 | 0.001 |
| 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) | 0.000 | 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".