The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.

中枢神经系统（CNS）具有自身的免疫系统，该系统由薄壁组织中的小胶质细胞和血管周围空间中的CNS相关巨噬细胞（CAM），软脑膜，硬脑膜和脉络丛组成。在了解中枢神经系统驻留的免疫细胞方面的最新进展为免疫防护的发展，成熟和功能提供了新的见解。小胶质细胞和CAM经历了环境因素以及整个胚胎和出生后发育过程中固有的转录程序触发的分化和成熟的基本步骤。这些整形步骤允许巨噬细胞适应其特定的生理功能，作为中枢神经系统及其界面的第一道防线。在婴儿期 中枢神经系统可能会被多种不同的病原体作为目标，这些病原体会导致严重的组织损伤，并可能造成长期的缺陷。因此，即使在这些早期阶段，也需要婴儿中枢神经系统巨噬细胞的有效免疫应答以清除感染，但也可能对发育中的中枢神经系统造成有害后果。在这里，我们着重介绍婴儿在胚胎和产后感染中的中枢神经系统免疫系统的最新知识以及对中枢神经系统发展的后果。