Cervical lymph nodes play the role of regional lymph nodes in brain tumourimmunity in rats

Recent physiological and anatomical studies have demonstrated that a major fraction of brain interstitial and cerebrospinal fluid drains into cervical lymph nodes (CLN) in a number of experimental animals, To investigate the role of CLN in brain tumour immunity, temporal profiles of MHC class II mol ecule expression and T lymphocyte subsets in brain tumours, CLN and other l ymphoid tissues were analysed by immunocytochemistry. A total of 64 Wistar rats weighing 250 g were used. Two weeks after the transplantation of C6 gl ioma cells (10(6) cells/l mu l) into a rat brain, expression of MHC class I I molecules was induced in the brain and all systemic lymphoid tissues exam ined. However, the subsequent appearance of CD4 or CD8 positive cells was s trictly confined to CLN, and coincided with the infiltration of such cells into the brain tumour 2 weeks after transplantation. In the group of animal s in which cervical lymphadenectomy was followed by intracerebral transplan tation of C6 glioma cells, infiltration of CD4 or CDS positive cells into t he brain tumour was delayed until 3 weeks after the transplantation, and th e production of such cells was by the spleen. These results suggest that CL N act as regional lymph nodes in brain tumour immunity.