in and out of TNC, in particular by increasing thymocyte release from TNCs. Thymocytes within TNC Incubation of TNC at 37 °C in tissue culture releases thymocytes (TNC-T) present within it. Incubation of TNC at 4 °C or room temperature inhibits release of TNC-T. Incubation of TNC at 37 °C in presence of 0.1% sodium azide prevents the release of TNC-T from within even though the TNC-T are viable. This suggests that metabolic activity of epithelial thymocyte complex is essential for the release of TNC-T. TNC-T are functionally mature than those external to TNC (ET). Unlike ET, mouse TNC-T cells proliferate following stimulation with alloantigen, mitogen and help B cell make antibody when tested in tissue culture experiments. Chicken TNC-T cells exhibit greater graft vs host reactivity than peripheral blood T cells or ET cells when TNCs from one strain of chicken were placed on egg choriallantoic membrane of another strain of chicken with different MHC antigen. Based on the observation that TNC harbor functionally mature population of TNC-T and the electronmicroscopic studies suggesting that TNCs are localized in close proximity of blood capillaries in both cortex and cortico-medullary region of thymus, Vakharia & Mitchison have hypothesized that TNC-T are potential thymus emigrant cells. Notes Epithelial cells