[Cell-mediated immune responses of patients with gastro-intestinal cancer to allogenic tumor-associated antigens].

Soluble tumor extract was prepared from cancer tissue of 172 patients with gastrointestinal cancer by the methods of hypertonic salt extraction (HSE) and 3M-KCL salt extraction (3M-KCL). Lymphocyte proliferative (LP) response and skin test was assessed with these tumor extracts. The LP response of cancer patients could be induced on 4 day-incubation in 10 micrograms.protein/ml of the extracts. The allogenic tumor extract induced the LP response with a close correlation to an autologous extract (p less than 0.001). Both HSE and 3M-KCL extracts induced a positive LP response as well as delayed hypersensitivity of the skin in 20 to 30% with a good correlation (p less than 0.001). The clinical stage related closely to a responsibility of LP response and of skin test to the tumor extracts except in stage IV. Gel filtration with Sephadex G-200 revealed the 5th graduated fraction (M.W. less than 10,000) responsible for the activity of LP test. The LP cancer could be demonstrated by LP response and skin test with the tumor extract prepared by HSE and 3M-KCL methods. Thus, it was concluded that the LP response and skin test is a useful parameter of tumor-specific immune response.