Splenectomy abolishes antitumor effect of immunotherapy with streptococcal preparation, OK-432, on mouse liver tumors.
In the present study, we investigated the therapeutic effects of oral and subcutaneous administration of OK-432 prior to or following the transplantation of murine liver tumors. In addition, the effect of splenectomy on the antitumor activity of OK-432 was investigated. Mice which received OK-432 orally prior to tumor transplantation exhibited significantly lower tumor weight and significantly improved survival, when compared to the control mice. Prior subcutaneous injection of OK-432 did not show any antitumor activity. On the other hand, both oral and subcutaneous administration of OK-432, subsequent to tumor transplantation, led to a significant improvement of survival and a decrease in the number of lung metastases, although tumor weight was not affected. The anti-tumor effect of OK-432 required the presence of the spleen, since the survival of the mice with liver tumors was not improved by OK-432 if splenectomy and tumor transplantation were performed simultaneously. These results suggest that immunotherapy with OK-432 may beneficial in the treatment of liver tumors and that these effects are dependent on the presence of the spleen.
Imai
S
S
First Department of Surgery, Kyoto University Faculty of Medicine, Japan.
Nio
Y
Y
Shiraishi
T
T
Tsubono
M
M
Morimoto
H
H
Tseng
C C
CC
Kawabata
K
K
Masai
Y
Y
Tobe
T
T
D000818:Animals; D007167:Immunotherapy; D008114:Liver Neoplasms, Experimental / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D010844:Picibanil / Q000008:administration & dosage / Q000627:therapeutic use*; D013154:Spleen / Q000502:physiology*; D013156:Splenectomy; D015996:Survival Rate
D010844:Picibanil