Lymph nodes also contain macrophages , which are large cells that engulf bacteria and other foreign particles. Thus, lymph nodes function as filters that trap cancer cells, bacteria, and viruses. Lymph nodes play an important role in fighting infection, primarily in their roles in antibody production and lymphocyte storage. Lymphocytes Lymphocytes are a group of white blood cells that are the most important part of the human immune system. Lymphocytes come from bone marrow and from lymph glands.
Lymphocytes protect against the growth of tumors.
Lymphocytes also cause tissue-rejection during organ transplants. The effectiveness of vaccines is based on this memory function of lymphocytes. These plasma cells secrete vast quantities of immunoglobins or antibodies that are tailor-made to attack the specific antigens of the particular bacteria, leading to its destruction. T-cells , which are derived from white cells that the thymus gland transformed to perform a specialized function. T-cells secrete more than fifty different types of powerful chemical substances called lymphokines that contribute significantly to the functioning of the immune system.