Lymphoid tissue architecture. Experimental analysis of the origin and distribution of T-cells and B-cells.

The distribution of bone marrow-derived cells, thymus-derived cells and tissue-bound immunoglobulin was examined using indirect immunofluorescence. It was demonstrated that primary follicle small lymphocytes are bone-marrow derived in the absence of the thymus, they lack thymus-associated antigens, and bear high concentrations of surface-associated immunoglobulins. Thymus-antigen positive cells make up the majority of, if not all, diffuse cortex lymphocytes, do not bear concentrations of surface immunoglobulin detectable in this system, are found as rare cells in primary follicles, and are present in germinal centres. A mechanism is proposed for the thymus—bone marrow interaction in the immune response.