Correlation Between Enhancement of Natural Killer (NK) Activity by an Immunopotentiator (OK-432) and Resistance to Human Hepatoma Cell Implantation in Nude Mice

The relation of between spleen NK activity and the incidence of tumor take of a human hepatoma cell line (HCC-M) was investigated in nude mice. An immunopotentiator (OK-432) was intraperitoneally administered to a group of nude mice (n=7) one and three days prior to the implantation of HCC-M cells. Transplantability was significantly decreased to 42.8%, p<0.005 by pretreatment with OK-432 compared to 100% in an untreated group (n=18). And this effect was abrogated by simultaneous administration with anti-asialo GMI antiserum and complement. It was indicated that treatment of OK-432 was effective to inhibition of tumor bearing because of activation of NK activity. It is demonstrated that peripheral blood NK activity of patients with liver cirrhosis is significantly decreased compared with that of healthy control. So it is expected that administration of OK-432 to patients with liver cirrhosis who consist a high risk group of hepatoma is possibly effective in preventing tumor development.