The immune reactivity of the regional and distant lymph nodes to autochthonous ovine squamous cell carcinomata

Anti-tumor immune reactivity of lymphocytes derived from lymph nodes regional to and distant from tumor growth, as well as that of peripheral blood leucocytes, against autochthonous tumor cells, was investigated. Experiments were carried out in vitro using a 51Cr cytotoxic assay and in vivo by cannulating the afferent and efferent lymphatics of regional and distant lymph nodes and challenging via the afferent lymphatics with 10(7) cultivated autochthonous tumor cells. No anti-tumor cytotoxic reactivity was detected in vitro using lymphocytes derived from any of the sources studied. In vivo, while challenge with autochthonous tumor cells produced no response in the regional lymph node, significant blast cell response was obtained in the distant node. The response at the distant node was associated with the production of antibodies that could bind to tumor cells without causing their demise. The anergy observed at the regional lymph node, and the possibility of a relation between the events occurring at that node and those observed at the distant node, are discussed.