Influences of operative stress on cell‐mediated immunity and on tumor metastasis and their prevention by nonspecific immunotherapy: Experimental studies in rats

Abstract

Influences of operative stress on nonspecific cell-mediated immunity and on liability to tumor metastasis and preventive effects thereon of a nonspecific immunopotentiator OK-432 were examined. Syngeneic female SD rats were inoculated SC with 200 mg of a transplantable mammary carcinoma MRMT-1 at the dorsal flank. After 2 weeks the tumor was surgically excised simply or combined with 30-min laparotomy. It was revealed by follow-up examination that the laparotomy stress significantly increased incidence of postoperative lung metastasis. It was found that PHA-induced blastogenesis of peripheral lymphocytes was markedly reduced in the early period following laparotomy. Preoperative or post-operative (especially the former) administration of OK-432 was effective for preventing both the postlaparotomy facilitation of lung metastasis and the postlaparotomy reduction in PHA lymphoblastogenesis.