Correlation of in vitro immune response with clinical course of malignant neoplasia in dogs.

An attempt was made to quantify the host antitumor immune response in 16 dogs with progressively growing tumors by evaluating the in vitro reactivity of their lymph node or peripheral blood lymphocytes to their own tumor cells. Serum from dogs with the same histologic type of neoplasm inhibited allogenic lymphocyte cytotoxicity, whereas serum from normal dogs, and a dog clinically free of osteosarcoma 17 months after limb amputation, did not significantly block cell-mediated reactivity. Low ratios of sensitized lymphocytes to tumor cells often stimulated tumor cell growth in vitro. Autologous serum from dogs with progressively growing neoplasms appeared to potentiate the stimulation of tumor growth above a simple blocking of lymphocyte-mediated cytotoxicity. An attempt was made to correlate the in vitro immune reactivity of the dog to the clinical behavior of its neoplasm. There was fair to good correlation in 12 dogs and no correlation in the remaining 4 dogs.