a collection of putative macrophages, first described by Aschoff based on their ability to phagocytose dye, which included most of the true macrophages (now classified under the mononuclear phagocytic system) as well as cells lining the sinusoids of the spleen, lymph nodes, and bone marrow, and the fibroblastic reticular cells of hematopoietic tissues; all these latter cells are only weakly phagocytic and are not true macrophages. The RES functions to remove particulates and soluble antigen from the bloodstream but it also generates numerous inflammatory mediators, in response to immunogenic stimulation. The term persists in the literature and is often equated with the mononuclear phagocytic system.
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Examples: glitazone, GI cocktail, etc.