Lymphocytes In Lymphoid Organs Research Articles

Migration of B lymphocytes in lymphoid organs of lethally irradiated, thymocyte-reconstituted mice.

The migration of radiolabeled intravenously injected B lymphocytes through thymus-dependent areas was studied in lymphoid organs of mice with experimentally defined T cell domains (B cell-deprived mice or "T" mice). In the spleen, B cells were found to enter the peri-arteriolar lymphoid sheath (PALS) by two routes: (i) via the marginal zone, and (ii) via reticulum sheaths surrounding terminal arterioles. B cells migrated through the peripheral and central PALS and initiated the formation of primary follicles in the peripheral PALS 6 h after injection. Distinct primary follicles were noted at 18 h after injection of the labelled B cells. After 24 h small numbers of labelled cells were also noted in the efferent lymphatic vessels of the spleen. The reconstitution of B cell compartments in the mesenteric lymph node was delayed compared to the spleen. B cells entered the nodal stroma across the wall of high endothelial venules in the paracortex and by 6 h were found scattered throughout the paracortex. Isolated clusters of a few labeled cells were noted in the outer cortex at 18 h after cell transfer. Defined primary nodules were seen only 24 h after reconstitution. A minority of labeled cells was found at 24 h in the cortico-medullary junctions and in medullary cords. The present study shows that B lymphocytes traverse T cell domains on their way to their own specific B cell compartments. The immunological significance of this particular migration route is discussed in view of data on the cellular cooperation of B cells, T cells and macrophages during the humoral immune response.

Greater Sensitivity to Inhibition by Anti-Immunoglobulin of Splenic than of Bone Marrow B-Lymphocytes

Abstract Bone marrow derived (B)3 lymphocytes in lymphoid organs represent the precursors of antibody-producing cells and are known to bear immunoglobulin molecules on their cell surface representative of the antibody ultimately to be produced. It has been suggested that B-cells in bone marrow, although at least partially sensitive (1), are more resistant than splenic B-cells to inactivation by incubation with highly radioactive antigen (2). Similarly, induction of tolerance by injection of ultracentrifuged human γ globulin (HGG) occurs much more rapidly in B-cells of the spleen than of the bone marrow (3). In light of these observations and in view of the fact that Ig receptors on the surface of B-cells most probably mediate their interaction with antigen, it seemed interesting to compare the relative sensitivities of mouse bone marrow and spleen precursors of antibody-forming cells to inactivation by anti-Ig antisera.

Studies on Heterologous Anti-Lymphocyte Serum in Mice

Summary Rabbits were immunized with suspensions of lymph node cells from A/Jax mice. The resulting antiserum (RAMLS) contained antibodies to A/Jax lymph node cells, demonstrable as cytotoxins and agglutinins, and antibodies to other mouse tissues and mouse serum proteins demonstrable as precipitins. The RAMLS caused a specific lymphopenia when given to mice. Absorption of antibodies to nonlymphatic mouse tissues and to mouse serum proteins did not alter the cytotoxic or agglutinating effect of the RAMLS on lymphocytes and did not alter the in vivo lymphopenic effect. Chronic administration of RAMLS resulted in sustained lymphopenia during the period of serum treatment without significant morbidity or mortality. Mice chronically treated with RAMLS do not make antibody to rabbit γ-globulin as readily as those given normal rabbit serum. Histologic studies of mice chronically treated with RAMLS show depletion and destruction of tissue lymphocytes in lymphoid organs. A similar state of profound lymphocyte depletion can be achieved by a short, intensive course of RAMLS treatment.