Columbia Center for Translational Immunology, Department of Medicine, Columbia University Medical Center, New York, New York, USA.
Department of Surgery, University of California San Francisco, San Francisco, California, USA.
JCI Insight. 2018 Nov 15;3(22):124086. doi: 10.1172/jci.insight.124086.
Allograft tolerance, in which a graft is accepted without long-term immunosuppression, could overcome numerous obstacles in transplantation. Human allograft tolerance has been intentionally induced across HLA barriers via combined kidney and bone marrow transplantation (CKBMT) with a regimen that induces only transient chimerism. Tregs are enriched early after CKBMT. While deletional tolerance contributes to long-term tolerance, the role of Tregs remains unclear. We have optimized a method for identifying the donor-specific Treg repertoire and used it to interrogate the fate of donor-specific Tregs after CKBMT. We expanded Tregs with several different protocols. Using functional analyses and T cell receptor sequencing, we found that expanding sorted Tregs with activated donor B cells identified the broadest Treg repertoire with the greatest potency and donor specificity of suppression. This method outperformed both alloantigen stimulation with CTLA4Ig and sequencing of CFSElo cells from the primary mixed lymphocyte reaction. In 3 tolerant and 1 nontolerant CKBMT recipients, we sequenced donor-specific Tregs before transplant and tracked them after transplant. Preexisting donor-specific Tregs were expanded at 6 months after CKBMT in tolerant patients and were reduced in the nontolerant patient. These results suggest that early expansion of donor-specific Tregs is involved in tolerance induction following CKBMT.
同种异体移植耐受，即移植物在没有长期免疫抑制的情况下被接受，可能克服移植中的许多障碍。通过联合肾和骨髓移植（CKBMT），并采用仅诱导短暂嵌合的方案，已经在人类中有意诱导同种异体移植耐受，从而跨越 HLA 障碍。在 CKBMT 后早期富集 Treg。虽然缺失性耐受有助于长期耐受，但 Treg 的作用仍不清楚。我们已经优化了一种鉴定供体特异性 Treg 库的方法，并使用它来研究 CKBMT 后供体特异性 Treg 的命运。我们使用几种不同的方案来扩增 Treg。通过功能分析和 T 细胞受体测序，我们发现用激活的供体 B 细胞扩增分选的 Treg 可以识别最广泛的 Treg 库，具有最大的效力和供体特异性抑制作用。这种方法优于 CTLA4Ig 刺激同种异体反应和从原发性混合淋巴细胞反应中 CFSElo 细胞测序。在 3 名耐受和 1 名不耐受的 CKBMT 受者中，我们在移植前对供体特异性 Treg 进行了测序，并在移植后对其进行了追踪。在耐受患者中，在 CKBMT 后 6 个月时扩增了预先存在的供体特异性 Treg，而在不耐受患者中则减少了。这些结果表明，在 CKBMT 后，供体特异性 Treg 的早期扩增参与了耐受诱导。
