Balfour B M, Drexhage H A, Kamperdijk E W, Hoefsmit E C
Ciba Found Symp. 1981;84:281-301. doi: 10.1002/9780470720660.ch15.
The accessory functions attributed to macrophages, such as antigen presentation, are probably carried out by specialized, marrow-derived cells which always have Ia antigen on their surfaces. These cells are not actively phagocytic, but are mainly engaged in engulfing large volumes on fluid. They are found in the epidermis as sessile cells, the Langerhans cells, but some re-enter the dermis and appear in afferent lymph as actively moving, veiled cells. Here they are joined by other veiled cells which have differentiated in the dermis: both populations then enter the draining lymph node. A similar process of differentiation probably occurs in other specialized tissues leading to the formation of cells that enter the afferent lymph and become veiled cells. In the lymph node, veiled cells localize in the paracortex or T-dependent area and later differentiate into another sessile cell type, the interdigitating cell. The life-style of this family of cells appears to be well-adapted for the transport of antigen into the paracortex, an area from which free antigen is largely excluded, and it seems likely that T-cell activation is triggered by the arrival of veiled cells bearing a new antigen on their surfaces.
巨噬细胞的辅助功能，如抗原呈递，可能是由源自骨髓的特化细胞来执行的，这些细胞表面始终有Ia抗原。这些细胞并非活跃的吞噬细胞，主要负责吞噬大量液体。它们以无柄细胞的形式存在于表皮中，即朗格汉斯细胞，但有些会重新进入真皮，并以活跃移动的被膜细胞形式出现在传入淋巴管中。在这里，它们与在真皮中分化的其他被膜细胞会合：然后这两类细胞都进入引流淋巴结。类似的分化过程可能发生在其他特化组织中，导致形成进入传入淋巴管并成为被膜细胞的细胞。在淋巴结中，被膜细胞定位于副皮质区或T细胞依赖区，随后分化为另一种无柄细胞类型，即交错突细胞。这类细胞的生活方式似乎非常适合将抗原转运到副皮质区，而在这个区域游离抗原基本被排除在外，并且表面携带新抗原的被膜细胞的到来似乎有可能触发T细胞的激活。
