Lena-Britt Hägg

The restoration of the t-lymphoid system of nude mice. Lower efficiency of nonlymphoid, epithelial thymus grafts.

Abstract The T-cell deficiency of nude mice is due to an abnormal differentiation of the thymus epithelium; it can be persistently corrected by grafting a neonatal thymus. However, grafted adult thymuses or epithelial thymuses are not repopulated by large numbers of host-derived lymphocytes, as is the case when a whole neonatal thymus is grafted. Furthermore, the repopulation of the spleen and lymph nodes by T cells is less pronounced than after whole neonatal thymus transplantation, and the restoration of the reactivity to T-cell mitogens is irregular. Therefore, the integrity and the age of the thymus graft are important for a good restoration of the T-lymphoid system of congenitally athymic animals.

Incomplete restoration of t-cell reactivity in nude mice after neonatal allogeneic thymus grafting.

Abstract Grafting an allogeneic neonatal thymus to a congenitally athymic adult nude mouse allows a sufficient generation of φ-positive lymphocytes to bring their relative and absolute numbers close to the values found in normal mice. However, the T-cell characteristic reactivities of thymus-grafted nudes persistently remain low, especially the responsiveness of lymphoid cell suspensions to T-cell mitogens. In a series of thymus-grafted nudes, significant numbers of thymus donor type lymphocytes were found to persist for long periods of time within the grafted thymus, but their persistence could not be directly correlated with the acceptance of skin of same strain origin as the thymus or with responsiveness to mitogens.

Ontogeny of T Lymphocytes Studied in Athymic and Foetal Mice

Earlier studies on T lineage lymphocytes in congenitally athymic nude mice (1, 2) have been extended to surgically T deprived mice and early stages of embryogenesis. They permit the further characterisation of a new type of lymphocyte and its implication in T cell ontogeny.