Immunoprophylactic Potential of Cloned Shiga Toxin 2 B Subunit
Bibliographic record
Abstract
The Shiga toxins Stx1 and Stx2 contribute to the development of enterohemorrhagic O157: H7 Escherichia coli-mediated colitis and hemolytic-uremic syndrome in humans.The Stx2 B subunit, which binds to globotriaosylceramide (GB3) receptors on target cells, was cloned.This involved replacing the Stx2 B subunit leader peptide nucleotide sequences with those from the Stx1 B subunit.The construct was expressed in the TOPP3 E. coli strain.The Stx2 B subunits from this strain assembled into a pentamer and bound to a GB3 receptor analogue.The cloned Stx2 B subunit was not cytotoxic to Vero cells or apoptogenic in Burkitt's lymphoma cells.Although their immune response to the Stx2 B subunit was variable, rabbits that developed Stx2 B subunit-specific antibodies, as determined by immunoblot and in vitro cytotoxicity neutralization assays, survived a challenge with Stx2 holotoxin.This is thought to be the first demonstration of the immunoprophylactic potential of the Stx2 B subunit.Enterohemorrhagic Escherichia coli (EHEC) cause hemorrhagic colitis (HC) and, on occasion, hemolytic-uremic syndrome (HUS), a life-threatening complication, in humans [1-4].EHEC are also known as Shiga toxin-producing E. coli (STEC) or Verotoxin-producing E. coli [5].Six different Shiga toxins (Stx) have been described, including one from Shigella dysenteriae, the closely related E. coli Stx1, and the more distantly related E. coli, Stx2, Stx2c, Stx2d, and Stx2e.The E. coli Stx1 and Stx2 are associated with STEC serotypes involved in human infections and are linked to the development of HC and HUS [6].Although all 6 varieties of Stx differ to some degree at the amino acid sequence level [7], these toxins are all multimeric proteins that display a classic AB5 structure [8,9].The Stx B subunits form a toroid-shaped pentamer that, with the exception of the Stx2e B subunit, recognizes globotriaosylceramide (GB3) receptors found on a number of different target cells [10][11][12].After receptor ligation, the host cell internalizes the
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".