Requirement for Q226, but not multiple charged residues, in the class I MHC CD loop/D strand for TCR‐activated CD8 accessory function
Bibliographic record
Abstract
Activation of CD8+ cytotoxic T lymphocytes typically begins with recognition of class I MHC-peptide complexes by the TCR and CD8 as a coreceptor. In its coreceptor role, CD8 binds thesame class I-peptide antigen complex as the TCR, enhancing the strength of TCR-class I interaction. Subsequent to initial TCR engagement, CD8 acts as an accessory molecule by binding any properly conformed class I molecules on the target cell surface, leading to CD8-mediated adhesion and cosignaling functions. We expressed and isolated a number of mutant class I molecules in which one or moreacidic or polar residues in the class I alpha3 domain CD loop and D strand region, or alpha2 domain were altered. Using solid phase CTL adhesion and degranulation assays with isolated class I molecules, we demonstrate that multiple acidic residues in the alpha3 domain, although involved in CD8 coreceptor interaction, are not required for TCR-activated CD8 accessory interactions. Instead, we show that Q226, a polar group on the end of the CD loop, is required for TCR-activated CD8 accessory functions. These results indicate that CD8 coreceptor and accessory interactions differ substantially and suggest that TCR activation results in changes that alter the structural constraints for CD8 accessory interactions.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".