lymphocytes bone lymph nodes. The organs of the immune system either make the cells that participate in the immune response or act as sites for immune function.These organs include the lymphatic vessels, lymph nodes, tonsils, thymus, Peyer's patch, and spleen.The lymph nodes are small aggregations of tissues interspersed throughout the lymphatic system. White blood cells (lymphocytes) that function in the immune response are concentrated in the lymph nodes.Lymphatic fluid circulates through the lymph nodes via the lymphatic vessels. As the lymph filters through the lymph nodes, foreign cells of microorganisms are detected and overpowered.he lymph nodes are small aggregations of tissues interspersed throughout the lymphatic system. White blood cells (lymphocytes) that function in the immune response are concentrated in the lymph nodes. Lymphatic fluid circulates through the lymph nodes via the lymphatic vessels.