Direct recognition of hepatocyte-expressed MHC class I alloantigens is required for tolerance induction
Moumita Paul-Heng, … , G. Alex Bishop, Alexandra Sharland
Moumita Paul-Heng, … , G. Alex Bishop, Alexandra Sharland
Published August 9, 2018
Citation Information: JCI Insight. 2018;3(15):e97500. https://doi.org/10.1172/jci.insight.97500.
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Research Article Hepatology Transplantation

Direct recognition of hepatocyte-expressed MHC class I alloantigens is required for tolerance induction

Abstract

Adeno-associated viral vector–mediated (AAV-mediated) expression of allogeneic major histocompatibility complex class I (MHC class I) in recipient liver induces donor-specific tolerance in mouse skin transplant models in which a class I allele (H-2Kb or H-2Kd) is mismatched between donor and recipient. Tolerance can be induced in mice primed by prior rejection of a donor-strain skin graft, as well as in naive recipients. Allogeneic MHC class I may be recognized by recipient T cells as an intact molecule (direct recognition) or may be processed and presented as an allogeneic peptide in the context of self-MHC (indirect recognition). The relative contributions of direct and indirect allorecognition to tolerance induction in this setting are unknown. Using hepatocyte-specific AAV vectors encoding WT allogeneic MHC class I molecules, or class I molecules containing a point mutation (D227K) that impedes direct recognition of intact allogeneic MHC class I by CD8+ T cells without hampering the presentation of processed peptides derived from allogeneic MHC class I, we show here that tolerance induction depends upon recognition of intact MHC class I. Indirect recognition alone yielded a modest prolongation of subsequent skin graft survival, attributable to the generation of CD4+ Tregs, but it was not sufficient to induce tolerance.

Authors

Moumita Paul-Heng, Mario Leong, Eithne Cunningham, Daniel L. J. Bunker, Katherine Bremner, Zane Wang, Chuanmin Wang, Szun Szun Tay, Claire McGuffog, Grant J. Logan, Ian E. Alexander, Min Hu, Stephen I. Alexander, Tim D. Sparwasser, Patrick Bertolino, David G. Bowen, G. Alex Bishop, Alexandra Sharland

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Figure 3

The D227K mutation of H2-Kb impairs direct recognition by Kb-specific CD8+ Des-RAG T cells.

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The D227K mutation of H2-Kb impairs direct recognition by Kb-specific CD...
(A) B10.BR mice were inoculated with 5 × 1011 vgc AAV-Kb or Kb-D227K. Two days later, 1 × 106 CFSE-labeled Des-RAG lymph node cells were adoptively transferred to these recipient mice. After a further 48 hours, liver leucocytes were isolated, stained, and examined by flow cytometry. (B and C) Des-RAG cells transferred into mice transduced with AAV-Kb expressed the activation markers CD69 (B) and PD-1 (C) and had started to divide. In contrast, Des-RAG cells recovered from the livers of mice inoculated with AAV-Kb-D227K showed no signs of activation or proliferation. (D) Consistent with the observed difference in the extent of proliferation between Des-RAG cells transferred to mice inoculated with AAV-Kb or Kb-D227K vectors, the absolute number of Des-RAG cells recovered from the Kb-expressing livers was 56,421 ± 13,959, compared with 2,482 ± 861 cells recovered from livers expressing Kb-D227K; P = 0.02. (E) Des-RAG T cells comprised 3.78% ± 1.12% of leucocytes recovered from the livers of mice transduced with AAV-Kb and 0.19% of liver leucocytes in AAV-Kb-D227K–treated mice (P = 0.04). This experiment was performed twice with 3–4 mice/group for each experiment. Representative dot plots are shown. Box shows minimum to maximum, with a line at the mean. Data are described as mean ± SEM and were analyzed using an unpaired t test.