Conventional CD4⁺ and CD8⁺ T lymphocytes comprise a mixture of naive and memory cells. Generation and survival of these T-cell subsets is under strict homeostatic control and reflects contact with self–major histocompatibility complex (MHC) and certain cytokines. Naive T cells arise in the thymus via T-cell receptor (TCR)-dependent positive selection to self-peptide/MHC complexes and are then maintained in the periphery through self-MHC interaction plus stimulation via interleukin-7 (IL-7). By contrast, memory T cells are largely MHC-independent for their survival but depend strongly on stimulation via cytokines. Whereas typical memory T cells are generated in response to foreign antigens, some arise spontaneously through contact of naive precursors with self-MHC ligands; we refer to these cells as memory-phenotype (MP) T cells. In this review, we discuss the generation and homeostasis of naive T cells and these two types of memory T cells, focusing on their relative interaction with MHC ligands and cytokines.

中文翻译：

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幼稚 T 淋巴细胞和记忆 T 淋巴细胞的稳态

传统的 CD4 ⁺和 CD8 ⁺ T 淋巴细胞包含幼稚细胞和记忆细胞的混合物。这些 T 细胞亚群的生成和存活受到严格的稳态控制，反映了与自身主要组织相容性复合体 (MHC) 和某些细胞因子的接触。初始 T 细胞通过 T 细胞受体 (TCR) 依赖性对自身肽/MHC 复合物的正选择在胸腺中产生，然后通过自身 MHC 相互作用加上白细胞介素 7 (IL-7) 的刺激而维持在外周。相比之下，记忆 T 细胞的生存很大程度上不依赖于 MHC，但强烈依赖于细胞因子的刺激。虽然典型的记忆 T 细胞是响应外来抗原而产生的，但有些记忆 T 细胞是通过幼稚前体细胞与自身 MHC 配体接触而自发产生的。我们将这些细胞称为记忆表型 (MP) T 细胞。在这篇综述中，我们讨论了初始 T 细胞和这两类记忆 T 细胞的生成和稳态，重点关注它们与 MHC 配体和细胞因子的相对相互作用。