The ability of the innate and adaptive immune systems to communicate with each other is central to protective immune responses and maintenance of host health. Myeloid cells of the innate immune system are able to sense microbial ligands, perturbations in cellular homeostasis, and virulence factors, thereby allowing them to relay distinct pathogen-specific information to naïve T cells in the form of pathogen-derived peptides and a unique cytokine milieu. Once primed, effector T helper cells produce lineage-defining cytokines to help combat the original pathogen, and a subset of these cells persist as memory or effector-memory populations. These memory T cells then play a dual role in host protection by not only responding rapidly to reinfection, but by also directly instructing myeloid cells to express licensing cytokines. This means there is a bi-directional flow of information first from the innate to the adaptive immune system, and then from the adaptive back to innate immune system. Here, we focus on how signals, first from pathogens and then from primed effector and memory T cells, are integrated by myeloid cells and its consequences for protective immunity or systemic inflammation.

先天性免疫系统和适应性免疫系统相互沟通的能力对于保护性免疫反应和维持宿主健康至关重要。先天免疫系统的骨髓细胞能够感知微生物配体、细胞稳态的扰动和毒力因子，从而使它们能够以病原体衍生肽和独特的细胞因子环境的形式将独特的病原体特异性信息传递给幼稚 T 细胞。一旦启动，效应T辅助细胞就会产生谱系定义细胞因子来帮助对抗原始病原体，并且这些细胞的一个子集会作为记忆或效应记忆群体持续存在。然后，这些记忆 T 细胞在宿主保护中发挥双重作用，不仅对再感染做出快速反应，而且还直接指示骨髓细胞表达许可细胞因子。这意味着信息首先从先天性免疫系统流向适应性免疫系统，然后从适应性免疫系统流回先天性免疫系统。在这里，我们重点关注骨髓细胞如何整合信号（首先来自病原体，然后来自启动效应细胞和记忆 T 细胞）及其对保护性免疫或全身炎症的影响。