Use of the popliteal lymph node enlargement assay to measure rat T cell function in immunotoxicologic testing

Modifications to the host vs graft response assay (HvGR) which render this technique suitable as an in vivo screen of cell-mediated immune function are described. This method utilizes mitotically inactivated spleen cells from normal heterozygous "nude" rats as stimulator population. We injected these cells into the left hind foot pad of unsensitized Charles River CD rats. Within one week, the recipients are sacrificed and both popliteal lymph nodes removed and weighed. The difference in weight between the challenged and unchallenged node represents the primary T cell response to the injected antigen sequestered in the draining lymph node. Using the immunosuppressive agents cyclophosphamide and dexamethasone we demonstrate the applicability of this assay to detect impaired cell-mediated immune function.