Antibody formation in mouse bone marrow

lymphoid organs are generally subdivided into two groups according to their contribution to antibody formation: 'primary 1 and 'secondari lymphoid organs. In mammals bone marrow and thymus are considered to be 'primar/ because these organs are involved in the generation of lymphocytes: B cells and T cells respectively. These lymphocytes can ieave t·heir place of origin and provide for antibody formation in secondary lymphoid organs: sp!een, lymph nodesr Peyer1s patches and other gut-associated lymphoid tissue. After antigenic stimulation B cells can potentialfy differentiate into antibody producing plasma cells. T cells play a principal role in cell-mediated immune responses, which include delayed hypersensitivity, contact sensitivity, graft rejection, graft-versus-host responses and acquired resistance to some microbes. In addition to be involved in cell-mediated immunity T cells cooperate with B cells in antibody formation to most antigens. Thereby T cells can enhance and suppress the response of the B cells to the antigen. Antigens which reguire cooperation of B cells and T celfs to evoke antibody formation are called 1thymus-dependent1 antigens in contrast to 1thymus-independent1 antigens which do not require T cells for antibody formation. There are suggestions in the I iterature that antibody formation in mammals can take place not only in secondary lymphoid organs but also in bone marrow: