Scheme of the medullar changes in lymph node after antigen stimulation

Upon antigenic stimulation the reticular cells that line the medullar sinusoids start to phagocytise the antigens (i.e. infective agents) and change from small tiny stellate cells into swollen large cells due to phagocytosis. They detach from the medullar sinus wall. After ten days the situation has been restored to normal appearance. A. normal medulla; B. acute antigen-stimulated medulla (after one to three days, phagocytosis); C. antigen-stimulated medulla (after ten days, recovery) 1. medullary cord; 2. medullary sinus ; 3. endothelial cell (littoral cell) of sinus ; 4. capillary within medullary cord; 5. reticular cell forming a reticular meshwork, and in contact with littoral cells; 6. monocyte; 7. lymphocyte (only few cells); 8. free circulating monocyte; 9. phagocytising littoral cell; 10. phagocytising reticular cell within cord; 11. detached phagocytising reticular cell in sinus (increased activity of reticular cells); 12. lymphocyte (there is an increase in amount of lymphocytes); 13. mature plasma cells (free circulating as well as localized within the cords); 14. young plasma cell