Dendritic cells (DCs) are crucial gatekeepers of the balance between immunity and tolerance. They exist in two functional states, immature or mature, that refer to an information-sensing versus an information-transmitting state, respectively. Historically, the term DC maturation was used to describe the acquisition of immunostimulatory capacity by DCs following their triggering by pathogens or tissue damage signals. As such, immature DCs were proposed to mediate tolerance, whereas mature DCs were associated with the induction of protective T cell immunity. Later studies have challenged this view and unequivocally demonstrated that two distinct modes of DC maturation exist, homeostatic and immunogenic DC maturation, each with a distinct functional outcome. Therefore, the mere expression of maturation markers cannot be used to predict immunogenicity. How DCs become activated in homeostatic conditions and maintain tolerance remains an area of intense debate. Several recent studies have shed light on the signals driving the homeostatic maturation programme, especially in the conventional type 1 DC (cDC1) compartment. Here, we highlight our growing understanding of homeostatic DC maturation and the relevance of this process for immune tolerance.

树突状细胞（DC）是免疫和耐受性之间平衡的重要守门人。它们存在两种功能状态：不成熟或成熟，分别指信息感知和信息传输状态。历史上，DC 成熟一词用于描述 DC 在被病原体或组织损伤信号触发后获得免疫刺激能力。因此，未成熟的 DC 被认为可以介导耐受性，而成熟的 DC 则与保护性 T 细胞免疫的诱导有关。后来的研究挑战了这一观点，并明确证明存在两种不同的 DC 成熟模式，即稳态和免疫原性 DC 成熟，每种模式都有不同的功能结果。因此，仅成熟标记物的表达不能用于预测免疫原性。 DCs如何在稳态条件下被激活并保持耐受性仍然是一个激烈争论的领域。最近的几项研究揭示了驱动稳态成熟程序的信号，特别是在传统的 1 型 DC (cDC1) 室中。在这里，我们强调我们对稳态 DC 成熟以及该过程与免疫耐受的相关性的不断了解。