La Jolla Institute for Allergy and Immunology, La Jolla, California, USA.
Adv Immunol. 2010;107:139-52. doi: 10.1016/B978-0-12-381300-8.00005-8.
Recent advances in stem cell research have redefined previous concepts of hematopoietic hierarchy, lineage commitment, and cell fate. The immune system is comprised of several well-defined cell lineages of which many exhibit high levels of plasticity or capacity in changing their phenotype. The CD4 T helper cells provide a peculiar example of apparently defined cell subsets, at times described as lineages, but also highly sensitive to tissue environmental cues that may change their fate. The classical Th1/Th2 CD4 T cell differentiation referred to for many years as the main CD4 T cell fate dichotomy and the later additions of CD4 helper T cell variants, such as T helper 17 (Th17) and induced regulatory T cells (iTreg), have added complexity but also doubts on the accuracy of defining CD4 T cell subsets as fixed T cell lineages.
近年来，干细胞研究的进展重新定义了以前对造血层次结构、谱系决定和细胞命运的概念。免疫系统由几个明确界定的细胞谱系组成，其中许多细胞表现出高度的可塑性或改变其表型的能力。CD4 T 辅助细胞提供了一个明显的细胞亚群的例子，有时被描述为谱系，但也对组织环境线索高度敏感，这些线索可能改变它们的命运。多年来，经典的 Th1/Th2 CD4 T 细胞分化被称为主要的 CD4 T 细胞命运二分法，后来又增加了 CD4 辅助 T 细胞变体，如 Th17（Th17）和诱导性调节 T 细胞（iTreg），这增加了复杂性，但也对将 CD4 T 细胞亚群定义为固定 T 细胞谱系的准确性产生了怀疑。
