Tingible body macrophage

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A tingible body macrophage.

A tingible body macrophage (TBMs) is a type of macrophage predominantly found in germinal centers, containing many phagocytized, apoptotic cells in various states of degradation, referred to as tingible bodies (tingible meaning stainable).[1] Tingible body macrophages contain condensed chromatin fragments.[2]

TBMs are licensed (empowered) for phagocytosis by follicular dendritic cells (FDCs).[3] FDCs provide TBMs with Milk fat globule-EGF factor 8 protein (Mfge8), which is a phosphatidylserine-binding "eat me" signal for removal of apoptotic germinal center B cells.[3]

It is thought that they may play a role in downregulating the germinal center reaction by the release of prostaglandins and hence a reduced B-cell induction of IL-2.[4]

Macrophages that contain debris from ingested lymphocytes are characteristic of a reactive follicular center in benign reactive lymphadenitis. Other accompanying signs of a benign follicular hyperplasia are well developed germinal centers with dark and light zones, in addition to numerous mitotic figures.

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