The B cell release antibodies and the T cell release lymphokines and antigen-specific effector T cells. The spleen is a large encapsulate lymphoid organ which filters out antigen from the blood stream. The cortex of the spleen contains packed lymphocytes with germinal centers and a medulla containing a variety of cell types. Basically there are two types of tissues in the spleen referred to as the lymphoid, or white pulp, of the cortex and the erythoid or red pulp, of the medulla. The T cells are diffusely packed in the white pulp, with the follicles primarily composed of B cells.
Most lymphocytes enter and leave the spleen by way of the bloodstream.
The red pulp is involved in removing old red blood cells and is reserve site for hemopoiesis during pathological states. Lymph Nodes Lymph nodes are small, bean-shaped organs that act as filters. They are located at major junctions of the network of lymphatic channels. They consist of an outer cortex and an inner medulla. If antigens enter the body via the respiratory or gastrointestinal tracts, they must pass through the lymph nodes.