EFFECT OF LYMPHOCYTES-T ON NORMAL HEMATOPOIESIS - STUDIES IN CONGENITALLY ATHYMIC NUDE-MICE

The germ-free nude mouse represents a most useful animal for investigating the effects of a congenital deficiency of T-lymphocytes on various physiological processes, including haemopoiesis. Nude mice (nu/nu) of the CBA strain, nonmutant inbred CBA mice, and inbred C3H mice were reared in germ-free isolators and used to compare (1) the haematological parameters of nu/nu mice and CBA mice at different ages and (2) the labelling pattern of circulating leucocytes at various times after a single intraperitoneal injection of3H-thymidine into 3-month-old nu/nu and C3H mice. The data suggest that the deficiency of T-lymphocytes in nu/nu mice may lead to a disturbance of haemopoiesis in 2 to 6-month-old animals which is characterised by a mild macrocytosis and a very marked reduction in the proportion of labelled leucocytes which can be seen in the blood after an injection of3H-thymidine. Despite these perturbations, unstressed nu/nu mice were able to maintain adequate numbers of blood cells (other than lymphocytes) in their circulation. Nine-month-old nu/nu mice did not show a macrocytosis and the disappearance of the macrocytosis at this age was associated with an increase both in the blood lymphocyte count and in the mass of lymphoid tissue in the spleen and mesenteric lymph nodes. © 1979 Springer-Verlag.