The spleen performs essential functions in the turnover of erythrocytes. It removes erythrocytes, metabolizes hemoglobin, and recycles iron. The spleen also mounts a primary immune response to antigens in the blood and synthesizes antibodies in its white pulp. Human splenic endothelial cells （HSEC）, resembling endothelial cells from other parts of the body, constitute the natural interface between the blood and the underlying tissue. Previous studies have demonstrated an intriguing link between splenic endothelial cells, splenic hamartoma and capillary hemangioma. Splenic endothelial cells have also shown a supportive micro-environment for the development of dendritic cells. Furthermore, rapid destruction of young erythrocytes can occur in spleen due to altered endothelial cell-macrophage interactions. These observations suggest that splenic endothelial cells play more compelling roles in the mononuclear phagocyte system. HSEC from AcceGen Research Laboratories are isolated from human spleen. HSEC are cryopreserved at passage one and delivered frozen. Each vial contains ＆gt;5×10^5 cells in 1 ml volume. HSEC are characterized by immunofluorescence with antibodies specific to VWF/Factor VIII and CD31 （P-CAM）, and by uptake of DiI-Ac-LDL. HSEC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HSEC are guaranteed to further expand for 15 population doublings under the conditions provided by AcceGen Research Laboratories.
