Background: Our research is focused on intestinal macrophages, which are believed to contribute to the maintenance of intestinal homeostasis. In addition, intestinal macrophages are unique in that there is an impairment of expression of tumor necrosis factor (TNF) from lipopolysaccharide (LPS). This characteristic can be attributed to the lack or poor level of expression of toll-like receptor 4 (TLR4) or CD14 on the membrane of intestinal macrophages. We therefore decided to identify where CD14 was localized in intestinal macrophages.
Materials and methods: The endoplasmic reticulum and Golgi apparatus were double stained and the intracellular localization in the intestinal macrophages was observed using a confocal laser microscope.
Results: CD14 of peritoneal macrophages was expressed both in the endoplasmic reticulum and Golgi apparatus. By contrast, intestinal macrophages expressed very little CD14 on the cellular membrane. CD14 was present in the endoplasmic reticulum of intestinal macrophages, but was rare in the Golgi apparatus.
Conclusion: The lack of expression of CD14 on the cell membrane of intestinal macrophages may be caused by transport interference from the endoplasmic reticulum to the Golgi apparatus.