A diphtheria toxin-interleukin 3 fusion protein is cytotoxic to primitive acute myeloid leukemia progenitors but spares normal progenitors.
Bibliographic record
Abstract
The relative cytotoxicity of a diphtheria toxin (DT) human interleukin 3(IL3) fusion protein (DT(388)IL3) was tested against primitive normal (n = 3)and acute myeloid leukemia (AML) progenitors (n = 7). After 24-h culture with 50 ng/ml DT(388)IL3, the mean percentages of kill of AML colony-forming cells (CFCs), long-term culture-initiating cells (LTC-ICs), and suspension culture-ICs (SC-ICs) were 82% (range, 47-100), 56% (range, 28-91), and 74% (range, 43-87), respectively, with most surviving progenitors being cytogenetically normal. Engraftment of DT(388)IL-3-treated AML cells in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice followed for 16 weeks was eradicated for two of these samples. In contrast, with normal bone marrow, mean percentages of CFC kill of 49 and 64% were seen with 50 or 250 ng/ml DT(388)IL3, respectively, whereas no significant kills were observed in the LTC-IC and SC-IC assays. The NOD/SCID mouse repopulating cell (RC) frequency in normal BM cells was also not reduced by DT(388)IL3 treatment. In subsequent experiments, NOD/SCID mice that received AML blasts i.v. followed in 24 h by 0.045 microg/g DT(388)IL3 daily i.p. x 5 showed mean percentages of reduction in AML engraftment of 83% (range, 14-100) and 57% (range, 0-98) after 4 and 12 weeks, respectively (n = 6). No evidence of leukemia was detected with two of six AML samples 12 weeks after one 5-day course of DT(388)IL3. Repeating the DT(388)IL3 treatment every 4 weeks enhanced its effectiveness against two additional samples. Thus, DT(388)IL3 kills primitive leukemic progenitors from a proportion of AML patients but shows no significant toxicity against equivalent normal cells.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".