The tonsils are part of the lymphatic system and are located in the pharynx. The tonsils are the immune system’s first defense against foreign pathogens and help to prevent respiratory and gastrointestinal infections. Tonsil endothelial cells (TEC) line the blood vessels and actively participate in fluid balance, cellular transport, and immunity. TEC also perform specialized functions for the tonsils including recruiting lymphocytes from the blood. Studies have shown that TEC express proteins that aid in lymphocyte adhesion and extravasation. Morphological and physiological changes in human TEC (HTEC) can lead to the development of tonsillitis. HTEC are a useful model for studying inflammation in the tonsils. HTEC from ScienCell Research Laboratories are isolated from human tonsil. HTEC are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HTEC are characterized by immunofluorescence with antibodies specific to vWF/Factor VIII and/or CD31 (PECAM1). HTEC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast, and fungi. HTEC are guaranteed to further expand for 10 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Endothelial Cell Medium (ECM, Cat. #1001) for culturing HTEC in vitro.