Macrophage-like cells in muscularis externa of mouse small intestine: immunohistochemical localization of F4/80, M1/70, and Ia-antigen.

Macrophage-like cells (MLC) in mouse small intestine are situated in the muscularis externa in the subserosal layer at the level of Auerbach's plexus, and at the level of the deep muscular plexus. By combined labelling with FITC-dextran and immunohistochemical techniques, the MLC were shown to express the macrophage markers F4/80 and M1/70.15. The MLC appeared to be constitutively IE-antigen-positive, but did not contain lysozyme. It is suggested that MLC, like Langerhans cells, belong to a specialized class of cells in the mononuclear phagocyte system.