From here they drain into the thoracic duct which empties into the subclavian artery, and around they go again. The cells in lymph are not just T and B cells but there are also various kinds of phagocytic cells, which are generally described as monocytes by morphology. At intervals along the lympatic vessels there are nodes or swellings where incomming cells are filtered over a bed of previous antigenic experiences. Inside the node T and B cells are sorted into separate areas. Somewhat surprising is that there is quite a strong migration of T cells from blood vessels that wind through the node and in fact the higest concentration of T cells is in the area that surrounds the post capillary venules.
B cells tend to accumulate in clusters called follicles.
After an strong antigenic encounter the local area of intense cellular proliferation is called a germinal center, and after the immune response has long gone, these germinal centers remain as shrunked cores that can be reactivated very quickly if the same antigen is encountered a second time. The blood also has a kind of node, but it is one big one for the entire blood supply, and it is called the spleen. The spleen is a generalized dump for junk in blood that should be filtered out and recycled-aged erythrocytes in particular. The center of the spleen is usually called the red pulp because of all the blood there, and the outer parts under the capsule are called the white pulp. There are again separate T and B areas.