Regulatory B cells (Bregs) ameliorate autoimmune disease and prevent allograft rejection. Conversely, they hinder effective clearance of pathogens and malignancies. Breg activity is mainly attributed to IL‐10 expression, but also utilizes additional regulatory mechanisms such as TGF‐β, FasL, IL‐35, and TIGIT. Although Bregs are present in various subsets defined by phenotypic markers (including canonical B cell subsets), our understanding of Bregs has been limited by the lack of a broadly inclusive and specific phenotypic or transcriptional marker. TIM‐1, a broad marker for Bregs first identified in transplant models, plays a major role in Breg maintenance and induction. Here, we expand on the role of TIM‐1⁺ Bregs in immune tolerance and propose TIM‐1 as a unifying marker for Bregs that utilize various inhibitory mechanisms in addition to IL‐10. Further, this review provides an in‐depth assessment of our understanding of Bregs in transplantation as elucidated in murine models and clinical studies. These studies highlight the major contribution of Bregs in preventing allograft rejection, and their ability to serve as highly predictive biomarkers for clinical transplant outcomes.

中文翻译：

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调节性 B 细胞：TIM-1、移植耐受和排斥

调节性 B 细胞 (Bregs) 可改善自身免疫性疾病并防止同种异体移植排斥。相反，它们会阻碍病原体和恶性肿瘤的有效清除。Breg 活性主要归因于 IL-10 表达，但也利用了其他调节机制，如 TGF-β、FasL、IL-35 和 TIGIT。尽管 Bregs 存在于由表型标记（包括典型 B 细胞子集）定义的各种子集中，但我们对 Bregs 的理解受到缺乏广泛包容和特定的表型或转录标记的限制。TIM-1 是首先在移植模型中发现的 Breg 的广泛标记物，在 Breg 维持和诱导中起着重要作用。在这里，我们扩展 TIM-1 ⁺的作用 Bregs 具有免疫耐受性，并提出 TIM-1 作为 Bregs 的统一标记物，除了 IL-10 外，还利用各种抑制机制。此外，本综述深入评估了我们对移植中 Bregs 的理解，正如在小鼠模型和临床研究中所阐明的那样。这些研究强调了 Bregs 在预防同种异体移植排斥方面的主要贡献，以及它们作为临床移植结果的高度预测生物标志物的能力。