Fu Jianing, Hsiao Thomas, Waffarn Elizabeth, Meng Wenzhao, Long Katherine D, Frangaj Kristjana, Jones Rebecca, Gorur Alaka, Shtewe Areen, Li Muyang, Muntnich Constanza Bay, Rogers Kortney, Jiao Wenyu, Velasco Monica, Matsumoto Rei, Kubota Masaru, Wells Steven, Danzl Nichole, Ravella Shilpa, Iuga Alina, Vasilescu Elena-Rodica, Griesemer Adam, Weiner Joshua, Farber Donna L, Luning Prak Eline T, Martinez Mercedes, Kato Tomoaki, Hershberg Uri, Sykes Megan
Columbia Center for Translational Immunology, Department of Medicine, Columbia University, New York, NY, USA.
Department of Human Biology, University of Haifa, Haifa, Israel.
medRxiv. 2023 Nov 16:2023.11.15.23298517. doi: 10.1101/2023.11.15.23298517.
It is unknown how intestinal B cell populations and B cell receptor (BCR) repertoires are established and maintained over time in humans. Following intestinal transplantation (ITx), surveillance ileal mucosal biopsies provide a unique opportunity to map the dynamic establishment of gut lymphocyte populations. Using polychromatic flow cytometry that includes HLA allele group-specific mAbs distinguishing donor from recipient cells along with high throughput BCR sequencing, we tracked the establishment of recipient B cell populations and BCR repertoire in the allograft mucosa of ITx recipients. We confirm the early presence of naïve donor B cells in the circulation and, for the first time, document the establishment of recipient B cell populations, including B resident memory cells, in the intestinal allograft mucosa. Recipient B cell repopulation of the allograft was most rapid in infant (<1 year old)-derived allografts and, unlike T cell repopulation, did not correlate with rejection rates. While recipient memory B cell populations were increased in graft mucosa compared to circulation, naïve recipient B cells remained detectable in the graft mucosa for years. Comparisons of peripheral and intra-mucosal B cell repertoires in the absence of rejection revealed increased BCR mutation rates and clonal expansion in graft mucosa compared to circulating B cells, but these parameters did not increase markedly after the first year post-transplant. Furthermore, clonal mixing between the allograft mucosa and the circulation was significantly greater in ITx recipients, even years after transplantation, than in healthy control adults. Collectively, our data demonstrate intestinal mucosal B cell repertoire establishment from a circulating pool, a process that continues for years without evidence of establishment of a stable mucosal B cell repertoire.
目前尚不清楚人类肠道B细胞群体和B细胞受体（BCR）库是如何随着时间的推移而建立和维持的。肠道移植（ITx）后，监测回肠黏膜活检为描绘肠道淋巴细胞群体的动态建立提供了独特的机会。我们使用多色流式细胞术，包括区分供体细胞和受体细胞的HLA等位基因组特异性单克隆抗体，以及高通量BCR测序，追踪了ITx受体同种异体移植物黏膜中受体B细胞群体和BCR库的建立情况。我们证实了循环中早期存在幼稚供体B细胞，并首次记录了肠道同种异体移植物黏膜中受体B细胞群体的建立，包括B驻留记忆细胞。在婴儿（<1岁）来源的同种异体移植物中，同种异体移植物中受体B细胞的重新填充最为迅速，并且与T细胞重新填充不同，与排斥率无关。虽然与循环相比，移植物黏膜中受体记忆B细胞群体增加，但幼稚受体B细胞在移植物黏膜中多年仍可检测到。在无排斥反应的情况下，对周围和黏膜内B细胞库的比较显示，与循环B细胞相比，移植物黏膜中的BCR突变率和克隆扩增增加，但这些参数在移植后第一年之后没有明显增加。此外，即使在移植多年后，ITx受体同种异体移植物黏膜和循环之间的克隆混合也明显大于健康对照成年人。总的来说，我们的数据表明肠道黏膜B细胞库是从循环池中建立的，这一过程持续数年，且没有证据表明建立了稳定的黏膜B细胞库。
