Human Bone Marrow Lymphocytes

Abstract

Abstract Lymphocytes from the bone marrow and peripheral blood of the same normal individuals were assayed simultaneously for blast transformation as well as polyclonal activation with differentiation to antibody-forming cells after stimulation with pokeweed mitogen. Blastogenic responses were measured by tritiated thymidine incorporation and antibody-forming cells were enumerated by a newly described hemolysis-in-gel plaque-forming cell assay. There was no significant difference between the blastogenic responses of lymphocytes in the peripheral blood compared to the bone marrow of the same individuals. However, differentiation to antibody-forming cells measured by the plaque-forming cell response was significantly greater in lymphocytes in the bone marrow as compared to peripheral blood of the same individuals. These studies demonstrate that the lymphocytes in human bone marrow are at a stage of differentiation whereby they can be readily induced to differentiation toward antibody production by polyclonal activation, even more so than peripheral blood lymphocytes. This supports the concept that the bone marrow is a major source of immunoglobulin production in man.