Augmentation of antitumor effect on syngeneic murine solid tumors by an interleukin 2 slow delivery system, the IL-2 mini-pellet.
We evaluated the antitumor effect of an interleukin 2 (IL-2) slow delivery system, the IL-2 mini-pellet, in two murine solid tumor models, and also investigated the enhancement of its therapeutic effect by serial administration. The IL-2 mini-pellet contains 1 x 10(6) units of IL-2 and releases it slowly in vivo. In our experiment, the IL-2 mini-pellet was administered subcutaneously near the tumor site in combination with the intravenous injection of lymphokine-activated killer (LAK) cells. When this regimen was given on days 8 and 11 after the subcutaneous inoculation of Meth A fibrosarcoma into BALB/c mice, tumor growth was significantly inhibited (p less than 0.05) compared to tumor growth in untreated controls. Moreover, the IL-2 mini-pellet alone was also effective in inhibiting tumor growth. In another experiment, MH134 hepatoma was inoculated into C3H/He mice. Both administration of the IL-2 mini-pellet alone and in combination with LAK cells resulted in complete tumor regression in four of five mice. In a third experiment, serial administration of the IL-2 mini-pellet at 3- or 5-day intervals prolonged the suppression of Meth A fibrosarcoma growth in BALB/c mice. These results suggested that the IL-2 mini-pellet could be applied to cancer immunotherapy and that its antitumor effect could be prolonged by serial administration.
Fujiwara
T
T
First Department of Surgery, Okayama University Medical School, Japan.
Sakagami
K
K
Matsuoka
J
J
Shiozaki
S
S
Fujioka
K
K
Takada
Y
Y
Uchida
S
S
Onoda
T
T
Orita
K
K
D000818:Animals; D003692:Delayed-Action Preparations; D004357:Drug Synergism; D005260:Female; D005354:Fibrosarcoma / Q000276:immunology / Q000628:therapy*; D007376:Interleukin-2 / Q000008:administration & dosage / Q000627:therapeutic use*; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology; D008114:Liver Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D014184:Transplantation, Homologous
D003692:Delayed-Action Preparations; D007376:Interleukin-2