Graft-versus-host disease (GVHD) is a complication of hematopoietic cell transplantation (HCT) caused by alloreactive T cells. Murine models of HCT are used to understand GVHD and T-cell reconstitution in GVHD target organs, most notably the gastrointestinal (GI) tract where the disease contributes most to patient mortality. T-cell receptor (TCR) repertoire sequencing was used to measure T-cell reconstitution from the same donor graft (C57BL/6 H-2b) in the GI tract of different recipients across a spectrum of matching, from syngeneic (C57BL/6), to minor histocompatibility (MHC) antigen mismatch BALB.B (H-2b), to major MHC mismatched B10.BR (H-2k) and BALB/c (H-2d). Although the donor T-cell pools had highly similar TCR, the TCR repertoire after HCT was very specific to recipients in each experiment independent of geography. A single invariant natural killer T clone was identifiable in every recipient group and was enriched in syngeneic recipients according to clonal count and confirmatory flow cytometry. Using a novel cluster analysis of the TCR repertoire, we could classify recipient groups based only on their CDR3 size distribution or TCR repertoire relatedness. Using a method for evaluating the contribution of common TCR motifs to relatedness, we found that reproducible sets of clones were associated with specific recipient groups within each experiment and that relatedness did not necessarily depend on the most common clones in allogeneic recipients. This finding suggests that TCR reconstitution is highly stochastic and likely does not depend on the evaluation of the most expanded TCR clones in any individual recipient but instead depends on a complex polyclonal architecture.
Bibliographical noteFunding Information:
This work was supported by the National Institutes of Health, National Heart, Lung, and Blood Institute (K08HL119590 and 2R01 HL56067), National Cancer Institute (PO1 CA049605), and National Institute of Allergy and Infectious Diseases (R37 AI 34495); and an Amy Manasevit Award from the National Marrow Donor Program and the American Society of Blood and Marrow Transplantation.
Conflict-of-interest disclosure: B.R.B. receives remuneration as an advisor to Kamon Pharmaceuticals, Inc., Five Prime Therapeutics Inc., Regeneron Pharmaceuticals, Magenta Therapeutics, and BlueRock Therapeutics; research support from Fate Therapeutics, RXi Pharmaceuticals, Alpine Immune Sciences, Inc, AbbVie Inc., the Leukemia and Lymphoma Society, Children’s Cancer Research Fund, and KidsFirst Fund; and is a cofounder of Tmunity. E.H.M. is a cofounder of GigaGen Inc. and Triursus Therapeutics Inc.; and has research support from Orca Biosystems. The remaining authors declare no competing financial interests.
© 2020 by The American Society of Hematology