Distribution and consequences of cell suspensions following intralymphatic infusion

The fate and consequences of intralymphatic injections of cells was investigated in dogs. The distribution of intact radiolabeled cells was determined in vivo by whole body gamma scanning. Comparison of distributions resulting from intralymphatic, subcutaneous, intradermal and intravenous routes of administration showed that the distribution and duration of radiolabel in various organs varied with the route of administration. Following intralymphatic injection, radiolabel was concentrated in first echelon lymph nodes draining the site of injection and was retained in these nodes for over 4 weeks. Histologic studies showed intense cortical and paracortical lymphopoiesis to be associated with the retention of intralymphatically injected tumor cells by first echelon lymph nodes. Serial histologic examination of lymph nodes from intralymphatically injected inbred beagles revealed that the consequent lymphopoiesis persisted for 5 weeks. In vitro evaluation of peripheral blood and lymph node lymphocyte cytotoxicity to the injected cells indicated that retention and nodal lymphopoiesis was associated with the development of direct lymphocyte cytotoxicity. The effects of concommitant tumor burden, cytotoxic drugs and ionizing radiation were also investigated and suggest that the therapeutic potential for use of the intralymphatic route has not yet been realized.