Activation of thymic T cells by MHC alloantigen requires syngeneic, activated CD4+ T cells and B cells as APC
Bibliographic record
Abstract
We examine here the in vitro requirements to activate immunocompetent T cells, present among thymocytes, to give rise to CTL, CD4+ T cells producing IL-2 and CD8+ T cells producing IFN-gamma. These thymocytes are naive in not having received antigen-dependent signals characteristic of the periphery. Their activation, upon stimulation with allogeneic spleen cells depleted of T cells, referred to here as allogeneic antigen-presenting cells (APCs), to produce allo-MHC-specific effector T cells, requires activated (radiation resistant) CD4+ T cells, syngeneic with the responding thymocytes. We refer here to these T cells as 'help'. Furthermore, optimal T cell activation requires an Ig+ B220+ cell in the allogeneic APC population, most probably a B cell. The allogeneic APCs cannot be replaced by conventional bone marrow (BM)-derived dendritic cells (DCs) activated by CD40 ligation or exposure to LPS. The requirements for both help and allogeneic B cells in the activation of thymocytes contrast with the requirements to generate substantial responses from splenic T cell populations. Activated, BM-derived DCs stimulate substantial splenic responses without help. These different requirements for activation could reflect the fact that thymocytes have not received an exit-thymus signal and/or that splenic T cells are heterogeneous, containing naive, memory and partially-activated T cells.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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 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".