Hagen Magdalena, Pangrazzi Luca, Rocamora-Reverte Lourdes, Weinberger Birgit
Institute for Biomedical Aging Research, University of Innsbruck, 6020 Innsbruck, Austria.
Biomedicines. 2023 Oct 5;11(10):2702. doi: 10.3390/biomedicines11102702.
The expression of CD4 and CD8 co-receptors defines two distinct T cell populations with specialized functions. While CD4 T cells support and modulate immune responses through different T-helper (Th) and regulatory subtypes, CD8 T cells eliminate cells that might threaten the organism, for example, virus-infected or tumor cells. However, a paradoxical population of CD4CD8 double-positive (DP) T cells challenging this paradigm has been found in the peripheral blood. This subset has been observed in healthy as well as pathological conditions, suggesting unique and well-defined functions. Furthermore, DP T cells express activation markers and exhibit memory-like features, displaying an effector memory (EM) and central memory (CM) phenotype. A subset expressing high CD4 (CD4) and intermediate CD8 (CD8) levels and a population of CD8CD4 T cells have been identified within DP T cells, suggesting that this small subpopulation may be heterogeneous. This review summarizes the current literature on DP T cells in humans in health and diseases. In addition, we point out that strategies to better characterize this minor T cell subset's role in regulating immune responses are necessary.
CD4和CD8共受体的表达定义了两个具有特殊功能的不同T细胞群体。CD4 T细胞通过不同的辅助性T细胞（Th）和调节性亚型来支持和调节免疫反应，而CD8 T细胞则清除可能威胁机体的细胞，例如病毒感染细胞或肿瘤细胞。然而，在外周血中发现了一个与这一范式相悖的CD4CD8双阳性（DP）T细胞群体。在健康和病理状态下均观察到了这一亚群，提示其具有独特且明确的功能。此外，DP T细胞表达激活标志物并表现出记忆样特征，呈现效应记忆（EM）和中枢记忆（CM）表型。在DP T细胞中已鉴定出一个高表达CD4（CD4hi）和中等水平CD8（CD8int）的亚群以及一群CD8hiCD4lo T细胞，这表明这个小亚群可能具有异质性。本综述总结了目前关于健康和疾病状态下人类DP T细胞的文献。此外，我们指出，有必要采取策略更好地描述这一微小T细胞亚群在调节免疫反应中的作用。
