Role of surface proteins SspA and SspB of Streptococcus gordonii in innate immunity
Bibliographic record
Abstract
Streptococcus gordonii, a normal inhabitant of the human oral cavity, is a potential live vaccine vehicle. Several pathogen-associated molecular patterns from S. gordonii that are recognized by antigen-presenting cells have recently been identified. In this study, we have identified that the cell-wall-anchored proteins SspA and SspB are immunostimulatory components of S. gordonii. SspA and SspB are members of the antigen I/II family of proteins widely expressed by viridans oral streptococci. The results showed that the mutant (OB219) lacking SspA and SspB had a reduced ability to induce cytokine/chemokine production in epithelial cells and bone-marrow-derived dendritic cells as compared with the parent strain (DL1). Purified SspA induced interleukin-6 and monocyte chemotatic protein-1 production from human lung epithelial A549 cells. The induction could be inhibited by a function-blocking anti-β1 integrin mAb and the purified SspA could bind to β1 integrin precoated on microtitre plates, suggesting that the induction was effected by SspA-β1 integrin interactions. The role of SspA and SspB in innate immunity was further demonstrated in a mouse intranasal challenge experiment, which showed that the clearance of OB219, the recruitment of neutrophils (as indicated by myeloperoxidase activity), and chemokine and cytokine production in the lungs of OB219-inoculated mice were delayed or reduced as compared with the DL1-inoculated mice. In addition to the above, S. gordonii OB219 was more sensitive to polymyxin, nisin and histatin-5 than DL1, suggesting that SspA and SspB also play a role in susceptibility to cationic antimicrobial peptides. Collectively, the results indicate that SspA and SspB are immunostimulatory components of S. gordonii and play an important role in modulating the host's innate immunity.
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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 | 0.000 | 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".