ABSTRACT
T lineage cells are found in the spleen of neonatal nu/nu mice born from nu/nu x nu/nu matings, and also in old, healthy nude mice obtained from the usual nu/+ x nu/nu matings. Their presence in neonatal nude mice which were never in contact with mother or normal littermate thymus products shows that commitment of stem cells towards the T lineage does not require the influence of the thymus.
Subject(s)
T-Lymphocytes , Aging , Animals , Animals, Newborn , Cell Count , Homozygote , Mice , Mice, NudeABSTRACT
Lymphocytes belonging to the T lineage were described in athymic nude mice. We showed previously that they were distinguished from usual peripheral lymphocytes by their low density of theta antigen, their slow electrophoretic mobility and their absence of recirculation through the thoracic duct. We now report that they also express the TL antigen, have a life span of 1 to 2 days, are produced in the bone marrow and are under the homeostatic influence of the thymus. Indeed they appear rapidly in surgically T-deprived mice and their production is blocked in both surgically or congenitally athymic mice receiving a thymus graft. This homeostatic control may be mediated via a humoral factor. Cells with similar characteristics are present in the thymus at early stages of embryogenesis. The characteristics of these T lineage lymphocytes strongly suggest that they may represent "pre-thymocytes", i.e. cells already committed to the T pathway independently of thymic influence but needing the thymus microenvironment to differentiate further.
Subject(s)
Isoantigens/analysis , Mice, Nude/immunology , T-Lymphocytes/immunology , Animals , Bone Marrow/immunology , Bone Marrow Cells , Cell Differentiation , Cell Survival , Female , Gestational Age , Male , Mice , Mice, Inbred BALB C , Receptors, Antigen, B-Cell/analysis , Spleen/immunology , T-Lymphocytes/cytology , Thymus Gland/embryology , Thymus Gland/immunologySubject(s)
Mice, Nude/immunology , T-Lymphocytes/immunology , Animals , Female , Homozygote , Male , MiceABSTRACT
The simultaneous detection of Ig and theta on the surface of mouse lymphocytes permits the detection of four cell types (Ig-theta-, Ig-theta+, Ig+theta-, and Ig+theta+) which also have distinct electrophoretic profiles. All types are present in variable proportions in all lymphoid organs studied. Results obtained in congenitally athymic nude mice and in T-deprived mice define a new type of lymphocyte, the Ig-theta+weak. This cell is non-recirculating, Ig-, with a low density of theta and a slow electrophoretic mobility. It is a candidate for a T-committed prethymic cell.