Fine Structure of the Reticuloendothelial System in the Spleen with Special Reference to the Red Pulp

Abstract

Electron microscopic observation of reticuloendothelial sytem was made in untreated albino rabbits and typhoid vaccine injected rabbits. On the bas_??_s of the findings obtained from panoramic electron microphotographs, the reticuloendothelial cells in the splenic red pulp could be classified into the sinus endothelial cell, fixed reticulum cell, ingesting reticulum cell and reticulum cell around the sheathed artery. Furthermore, the fixed reticulum cell was subdivided into two types by their location in the medullary cord; that is, the reticulum cell situated in the periphery of the cord, covering the outer surface of sinus basement membrane, and the cell situated in the center of the cord. Both fixed reticulumm cells formed the framework of the cord by extruding the cytoplasmic processes between other cells. The ingesting type of reticulum cell was different from the fixed reticulum cell and supposed to be derived from the immature lympho-reticular cell existing originally in the red pulp.
The sinus endothelial cell showed some resemblance to the reticulum cell when stimulated, and cytoplasmic organellae were increased.
In rabbits, the sheathed artery could be identified by the electron microscope and was surrounded by reticulum cells.