On March 15, 2007, Takeshi Watanabe and colleagues at the RIKEN institute in Japan used implanted artificial lymph nodes into mice. Lymph nodes are part of the lymphatic system which consists of organs, ducts, and nodes that transports a watery clear fluid called lymph. This lymph fluid is used to distribute immune cells called lymphocytes, cells of the immune system that defend the body against both infectious disease and foreign materials, throughout the body. The lymphatic system has many functions. One of the main functions is to collect and return interstitial fluid, including plasma protein to the blood. This helps to maintain fluid balance within the body. Some organs that help make up the lymphatic system include bone marrow, lymph nodes, spleen, and thymus. Human lymph nodes are bean-shaped and vary in size from a few millimeters to about 1 or 2 cm in their normal state. Lymph nodes are important to the body because they provide a place where the lymphocytes can receive initial exposure to a foreign antigen, which will activate the lymphocytes to perform their immune functions. A person dying of AIDS, cancer, or other diseases may have lymph nodes that no longer produce the immune cells necessary to fight of an infection. With the new artificial lymph nodes, the body will be able to produce lymphocytes that could aid in fighting off the disease.
Takeshi Watanabe and her colleagues used a “bioscaffold” made of collagen, and were filled with stromal and dendritic cells that were extracted from the thymus of newborn mice. Wantanabe and her crew then implanted the entire package into mice with healthy immune systems. These surrogate mice had previously been vaccinated against a harmless antigen. In a normal lymph node, stromal cells arrange the various components of the node, and aid in its development. Wantanabe found that the artificial lymph nodes worked the same way. The stomal cells that were implanted into the artificial...