KINETICS OF THE DISTRIBUTION OF THYMUS AND MARROW CELLS IN THE PERIPHERAL LYMPHOID ORGANS OF THE MOUSE : ECOTAXIS.

The differences between the fate of mouse thymus and marrow cells labelled in vitro with [³H]adenosine following intravenous injection into syngeneic recipients are defined. Thymus cells home predominantly to the thymus-dependent territory in the recipient's peripheral lymphoid organs, whereas the majority of bone marrow cells is found in thymus-independent sites. In addition, it is shown that a marrow inoculum contains a variety of sub-populations able to discriminate microenvironmental differences within the thymus-independent territory itself in general, cell populations behave as if they have the ability to distinguish and home towards what is probably their usual environment. The word `ecotaxis' is offered to define this phenomenon, and the mechanisms that may be involved in determining it are discussed. [ABSTRACT FROM AUTHOR]