[Ellipsoids of the spleen (ellipsoid macrophagal-lymphoid sheaths]

The ellipsoids of the spleen are considered as one of the links of the immune (lymphoid) apparatus of the lymphoreticular organ. Anatomical peculiarities of interrelations between the wall of the terminal part of the arterial bed, capillary, ellipsoid macrophagal-lymphoid microenvironment and reticular stroma of the ellipsoids of the spleen are discussed. Certain ultrastructural and immune-histological differences in the structure of the endothelial lining and cells, forming the ellipsoid sheaths, demonstrate functional interconnection of these formations not only with regulation of blood stream in the spleen vascular bed, but with transport of the antigenic material and lymphocytes into the white pulp. However, the functional appointment, as well as using of terminology of these formations still remain to be cleared out. An analogy is made, concerning the function of the splenic ellipsoid sheaths and postcapillary venules of the lymph node. The formation of the structural mechanism of immune response to the antigen-antibody complexes are analyzed, using some examples of evolutionary development of the ellipsoid macrophagal-lymphoid sheaths in various animal species.