Immune response in draining lymph nodes and Spleen After Intraventricular Injection of Antigen

Both Fischer 344 and Sprague Dawley rats showed significant numbers of antibody forming cells (PFC) in deep cervical lymph nodes after intraventricular injection of antigens, including trinitrophenylated (TNP)-hemocyanin, TNP-B. abortus and sheep erythrocytes. This indicated that particular as well as soluble antigens drained to these lymph nodes from the spinal fluid. Other lymph nodes examined did not show increased PFC over background, but levels of PFC in the spleen were significantly elevated after intraventricular injection of each of these antigens. Comparison with dose responses in the spleen after intravenous antigen injection suggested that approximately 20% of the intraventricularly injected immunogens drained to the peripheral blood. The relevance of these findings with respect to the brain as an immunologically privileged site is discussed.