These antibodies act by combining with, and neutralizing bacterial toxins, and by coating bacteria to enhance their chances of being phagocytized. These are the cells that effect the cell-mediated immunity that is demonstrated in skin graft or transplant rejection and the 'delayed' hypersensitivity response to tuberculin tests. On a functional basis then, the lymphoid organs are classified as and secondary lymphoid organs. The thymus and the bursa equivalent in man are the primary ones and all others are secondary.
Lymphocytes are present and are produced in the lymphatic tissues.
Monocytes too may be produced here. The interstices of this framework are filled with lymphocytes of various sizes and with plasma cells. The areas between nodules may also be dense but not well organized. Note the lympocyte infiltration into the overlying epithelium. These may not be readily visible.