Feuerstein Reinhild, Kolter Julia, Henneke Philipp
Center for Chronic Immunodeficiency, Medical Center and Faculty of Medicine, University of Freiburg, Germany.
Faculty of Biology, University of Freiburg, Germany; and.
J Leukoc Biol. 2017 Jan;101(1):99-106. doi: 10.1189/jlb.3MR0316-097RR. Epub 2016 Oct 12.
The dermis, a major reservoir of immune cells in immediate vicinity to the colonizing skin microflora, serves as an important site of host-pathogen interactions. Macrophages (Mϕ) are the most frequent resident immune cell type in the dermis. They protect the host from invasive infections by highly adapted bacteria, such as staphylococci via pattern recognition of bacterial effectors, phagocytosis, and recruitment of other myeloid cells from the blood. Already under homeostatic conditions, the dermal Mϕ population receives a dynamic input of monocytes invading from the bloodstream. This quantitative renewal is promoted further at the beginning of life, when prenatally seeded cells are rapidly replaced and in healing phases after injuries or infections. Here, we discuss the potential implications of the dynamic dermal Mϕ biology on the establishment and maintenance of immunity against Staphylococcus aureus, which can either be a harmless colonizer or an invasive pathogen. The understanding of the heterogeneity of the "mature" dermal Mϕ compartment driven both by the influx of differentiating monocytes and by a bone marrow-independent Mϕ persistence and expansion may help to explain failing immunity and immunopathology originating from the skin, the important interface between host and environment.
真皮是紧邻定殖于皮肤的微生物群的主要免疫细胞储存库，是宿主与病原体相互作用的重要场所。巨噬细胞（Mϕ）是真皮中最常见的常驻免疫细胞类型。它们通过对细菌效应物的模式识别、吞噬作用以及从血液中招募其他髓系细胞，保护宿主免受葡萄球菌等高度适应性细菌的侵袭性感染。即使在稳态条件下，真皮Mϕ群体也会不断接收从血液中侵入的单核细胞的动态输入。在生命初期，当产前植入的细胞迅速被替换时，以及在受伤或感染后的愈合阶段，这种定量更新会进一步加速。在这里，我们讨论真皮Mϕ动态生物学对建立和维持针对金黄色葡萄球菌免疫的潜在影响，金黄色葡萄球菌既可以是无害的定殖菌，也可以是侵袭性病原体。了解由分化单核细胞的流入以及不依赖骨髓的Mϕ持续存在和扩增所驱动的“成熟”真皮Mϕ区室的异质性，可能有助于解释源自皮肤（宿主与环境的重要界面）的免疫功能衰竭和免疫病理学现象。
