We are just beginning to understand the diversity of the peripheral T cell compartment, which arises from the specialization of different T cell subsets and the plasticity of individual naive T cells to adopt different fates. Although the progeny of a single T cell can differentiate into many phenotypes following infection, individual T cells are biased towards particular phenotypes. These biases are typically ascribed to random factors that occur during and after antigenic stimulation. However, the T cell compartment does not remain static with age, and shifting immune challenges during ontogeny give rise to T cells with distinct functional properties. Here, we argue that the developmental history of naive T cells creates a ‘hidden layer’ of diversity that persists into adulthood. Insight into this diversity can provide a new perspective on immunity and immunotherapy across the lifespan.

我们才刚刚开始理解外围T细胞区室的多样性，这是由于不同T细胞亚群的特殊化以及单个幼稚T细胞采用不同命运所产生的可塑性所致。尽管单个T细胞的后代可以在感染后分化为许多表型，但是单个T细胞倾向于特定的表型。这些偏见通常归因于在抗原刺激期间和之后发生的随机因素。但是，T细胞区室并不会随着年龄的增长而保持静止，并且在个体发育过程中转移免疫挑战会产生具有独特功能特性的T细胞。在这里，我们认为幼稚T细胞的发育史会造成多样性的“隐藏层”，并持续到成年。