The role and mechanisms of double negative regulatory T cells in the prevention of cardiac xenograft rejection
Bibliographic record
Abstract
We have previously identified peripheral alphabetaTCR+CD3 +CD4-CD8- double negative (DN) T cells as a distinct Treg subset. DN Tregs obtained from allograft-tolerant mice can suppress/kill anti-donor T cells in vitro in an antigen specific manner and prolong donor-specific allograft survival in recipient mice following adoptive transfer. In this thesis, I studied the role of DN Tregs in the prevention of organ xenograft rejection. I used a rat-to-mouse cardiac xenotransplantation model, in which CD4+ T cells play a critical role in rejecting xenografts since CD4+ T cell-deficient (CD4-/- ) mice failed to reject rat hearts. I demonstrate that a combination treatment of pretransplant donor lymphocyte infusion (DLI) and a short course of anti-CD4 depleting mAb, but not anti-CD4 mAb alone, induced permanent rat-heart survival in wild type mice. Adoptive transfer CD4+ T cells from DLI/anti-CD4-treated xenograft-accepted mice can induce rejection of rat hearts in CD4-/- mice, indicating the presence of functional anti-donor CD4 + T cells in xenograft-accepted mice. Interestingly, the number of DN Tregs was significantly increased in the secondary lymphoid organs of DLI/anti-CD4-treated xenografted mice when compared to that of anti-CD4-alone treated recipients. DN Tregs isolated from the secondary lymphoid organs of DLI/anti-CD4-, but not anti-CD4-, treated xenografted mice could suppress the in vitro proliferation of anti-donor CD4+ T cells in an antigen-specific manner. In addition, when the number and phenotype of graft-infiltrating cells were compared between anti-CD4- and DLI/anti-CD4-treated groups, I observed a significant increase in both the number and suppressive activity of DN Tregs in the xenografts of DLI/anti-lCD4-treated mice. Thus, DN Tregs may be involved in controlling anti-xenograft CD4+ T cell responses in both secondary lymphoid organs and xenografts. Furthermore, adoptive transfer DN Tregs from xenograft-accepted mice significantly inhibited the in vivo proliferation and cytokine production of transferred naive CD4+ T cells, and prevented transferred CD4+ T cell-mediated rejection of rat cardiac xenografts in CD4-/- mice. These data provide in vivo evidence that DN Tregs are able to control anti-xenograft CD4+ T cell responses. Taken together, I have shown that suppression of anti-donor CD4+ T cells by DN Tregs contributes to the maintenance of xenograft survival.
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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) | 0.000 | 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 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".