Cervical lymph cannulation to investigate the efflux and effects of intracerebroventricular cytokine infusions

It is well documented that there is communication between the cerebral spinal fluid (CSF) and cervical lymphatics. Recently, it has been demonstrated that tumor necrosis factor α (TNF-α) introduced into the CSF appears in the cervical lymph. However, the functional significance of this is less clear. Here we describe a protocol to quantitate the efflux of TNF-α from the CSF into cervical lymph. In addition, we describe a methodology to examine the effects of an intracerebroventricular (i.c.v.) infusion of TNF-α on lymph volume, cellularity and cell phenotype. While TNF-α was recovered in the cervical lymph following infusion of 125-I labeled TNF-α, the dosage of TNF-α used in this study had no effect on cervical lymph flow, cellularity or cell subsets. This protocol can be used to study the efflux of i.c.v. injected macromolecules and their effects on lymphocytes in cervical lymph and the regional lymph nodes.