Identification of an Expressed Truncated Form of CD200, CD200tr, which is a Physiologic Antagonist of CD200-Induced Suppression
Bibliographic record
Abstract
BACKGROUND: Earlier studies have indicated that cell surface expressed CD200, or a soluble form of this molecule, can induce immunosuppression in a number of biological systems, and promote increased graft acceptance, after binding to receptors (CD200Rs). Many groups have reported that the NH2-terminal region of CD200 is crucial for interaction with CD200R. METHODS: A truncated form of the full-length, immunosuppression-inducing molecule, CD200, representing translation of an mRNA splice variant, CD200tr, was expressed in the CHO cells and the transduced cells used to produce mAbs unique to CD200tr. These mAbs, and mAbs to full-length CD200, were used to document physiologic expression of full-length CD200 and CD200tr on lipopolysaccharide-stimulated dendritic cells (DCs). The ability of a soluble form of CD200 and CD200tr, each linked to a murine IgG2aFc, to suppress allogeneic immune responses in vitro (mixed leukocyte cultures) or in vivo (skin graft rejection) alone, or in combination, was studied. RESULTS: CHO cells expressing CD200tr inhibited the suppression of mixed leukocyte reactions seen after addition of soluble CD200 (CD200Fc) to culture. In addition, a soluble form of CD200tr, prepared by fusing the extracellular domain of the truncated CD200 to a murine IgG2a Fc region, could block in a competitive fashion the CD200Fc-mediated suppression of cytotoxic T lymphocyte induced in mixed leukocyte reactions, of tumor necrosis factor-alpha produced by lipopolysaccharide-stimulated splenic cells, and of allogeneic skin graft rejection in vivo. CONCLUSION: Taken together our data support the hypothesis that an expressed splice variant of CD200, CD200tr, is a physiologic antagonist of CD200.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".