Lymphokine-activated tumor inhibition in vivo. I. The local administration of interleukin 2 triggers nonreactive lymphocytes from tumor-bearing mice to inhibit tumor growth.
CE-2 is a chemically induced tumor of low immunogenicity in syngeneic BALB/c mice. Nylon wool columns eluting lymphocytes from the spleen of mice bearing clinically evident (5-mm mean diameter) CE-2 tumors (CE-2 TB lymphocytes) do not react with CE-2 cells in vitro, nor are they able to affect their growth in vivo in a Winn-type neutralization assay at 5:1 lymphocyte:tumor cell ratio. However, they become able to inhibit CE-2 tumor growth when 20 U of interleukin 2 (IL 2) in 0.4 ml are injected daily for 10 days at the challenge site. In contrast, mice injected with CE-2 cells and IL 2 only display tumor takes and growth that are not significantly different from those in controls challenged with CE-2 cells alone. This lymphokine-activated tumor inhibition (LATI) is not a peculiarity of the CE-2 tumor-host combination, because different tumors can be inhibited in this way and various TB lymphocytes can initiate it. In these experiments, IL 2-rich 25,000 to 30,000 m.w. fractions were obtained routinely from the culture supernatants of a clone of EL-4 thymoma stimulated with phorbol myristic acetate. Equally active IL 2-rich preparations were obtained from rat spleen cells stimulated with concanavalin A, or from MLA 144 gibbon lymphosarcoma spontaneously releasing IL 2. Treatment of CE-2 TB lymphocytes with various antibody and C, with 2000 rad gamma-irradiation, or fractionation on Percoll density gradients suggested that radioresistant functions of Thy-1.2+, Lyt-1.2+, Lyt-2.2- and of asialo GM1+ cells are independently involved in LATI induction. These lymphocytes inhibit tumor growth by recruiting the radiosensitive effector mechanisms of the recipient mice required for ultimate tumor destruction. CE-2 tumor inhibition by LATI leaves a specific delayed-type hypersensitivity and an immunologic memory, resulting in rejection of a second lethal CE-2 challenge in a significant number of mice.
D000230:Adenocarcinoma / Q000276:immunology; D000818:Animals; D005260:Female; D007279:Injections, Subcutaneous; D007376:Interleukin-2 / Q000008:administration & dosage* / Q000627:therapeutic use; D007518:Isoantibodies / Q000502:physiology; D008175:Lung Neoplasms / Q000276:immunology; D008213:Lymphocyte Activation; D017710:Lymphocyte Transfusion; D008214:Lymphocytes / Q000145:classification / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D012513:Sarcoma, Experimental / Q000276:immunology / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors
D007376:Interleukin-2; D007518:Isoantibodies; C029805:Lyt antibodies