Biomaterial Database

Thymic control of proliferation of T cell precursors in bone marrow. 1979

J J Cohen, and S S Fairchild

The activity of T lymphocyte precursors (pre-T cells) in the bone marrow of mice was measured by the concanavalin A response synergy assay. Pre-T cell levels were low in marrow of neonatally thymectomized mice and could be restored to control values by treatment in vivo with an extract of mouse thymus. Levels of activity were also low in aging mice and again could be restored by thymic extract treatment. The most profound fall with aging was in the proliferating pre-T cell compartment as detected by tritiated thymidine suicide; and this compartment was restored by thymic extract treatment. Irradiation to the thymus, with the bone marrow shielded, caused a fall in resting pre-T cells in the bone marrow and a concomitant rise in proliferating cells. These results are consistent with a model of control of pre-T cell maturation in which the thymus senses the number of developing lymphocytes within it and responds to a fall in this number by increasing production of hormone. The hormone acts on resting pre-T cells in the marrow, stimulating some of them to proliferate, leave the bone marrow, and repopulate the thymus.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D001854	Bone Marrow Cells	Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.	Bone Marrow Cell,Cell, Bone Marrow,Cells, Bone Marrow,Marrow Cell, Bone,Marrow Cells, Bone
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D005246	Feedback	A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.	Feedbacks
D006410	Hematopoiesis	The development and formation of various types of BLOOD CELLS. Hematopoiesis can take place in the BONE MARROW (medullary) or outside the bone marrow (HEMATOPOIESIS, EXTRAMEDULLARY).	Hematopoiesis, Medullary,Haematopoiesis,Medullary Hematopoiesis
D000375	Aging	The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.	Senescence,Aging, Biological,Biological Aging
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000831	Animals, Newborn	Refers to animals in the period of time just after birth.	Animals, Neonatal,Animal, Neonatal,Animal, Newborn,Neonatal Animal,Neonatal Animals,Newborn Animal,Newborn Animals
D013601	T-Lymphocytes	Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.	T Cell,T Lymphocyte,T-Cells,Thymus-Dependent Lymphocytes,Cell, T,Cells, T,Lymphocyte, T,Lymphocyte, Thymus-Dependent,Lymphocytes, T,Lymphocytes, Thymus-Dependent,T Cells,T Lymphocytes,T-Cell,T-Lymphocyte,Thymus Dependent Lymphocytes,Thymus-Dependent Lymphocyte
D013934	Thymectomy	Surgical removal of the thymus gland. (Dorland, 28th ed)	Thymectomies