Leukocyte migration is a fundamental component of innate and adaptive immune responses as it governs the recruitment and localization of these motile cells, which is crucial for immune cell priming, effector functions, memory responses and immune regulation. This complex cellular trafficking system is controlled to a large extent via highly regulated production of secreted chemokines and the restricted expression of their membrane-tethered G-protein-coupled receptors. The activity of chemokines and their receptors is also regulated by a subfamily of molecules known as atypical chemokine receptors (ACKRs), which are chemokine receptor-like molecules that do not couple to the classical signalling pathways that promote cell migration in response to chemokine ligation. There has been a great deal of progress in understanding the biology of these receptors and their functions in the immune system in the past decade. Here, we describe the contribution of the various ACKRs to innate and adaptive immune responses, focussing specifically on recent progress. This includes recent findings that have defined the role for ACKRs in sculpting extracellular chemokine gradients, findings that broaden the spectrum of chemokine ligands recognized by these receptors, candidate new additions to ACKR family, and our increasing understanding of the role of these receptors in shaping the migration of innate and adaptive immune cells.

白细胞迁移是先天性和适应性免疫反应的基本组成部分，因为它控制着这些运动细胞的招募和定位，这对于免疫细胞启动、效应器功能、记忆反应和免疫调节至关重要。这种复杂的细胞运输系统在很大程度上是通过高度调节分泌趋化因子的产生及其膜束缚的 G 蛋白偶联受体的限制表达来控制的。趋化因子及其受体的活性还受到非典型趋化因子受体 (ACKR) 分子亚家族的调节，这些分子是趋化因子受体样分子，不与响应趋化因子连接而促进细胞迁移的经典信号传导途径偶联。在过去的十年中，在了解这些受体的生物学及其在免疫系统中的功能方面取得了很大进展。在这里，我们描述了各种 ACKR 对先天性和适应性免疫反应的贡献，特别关注最新进展。这包括最近的发现，这些发现定义了 ACKR 在塑造细胞外趋化因子梯度中的作用，拓宽了这些受体识别的趋化因子配体谱的发现，ACKR 家族的候选新成员，以及我们对这些受体在塑造细胞外趋化因子梯度中的作用的日益了解。先天性和适应性免疫细胞的迁移。