DIMINUTION OF CYCLOPHOSPHAMIDE-INDUCED SUPPRESSION OF ANTI-TUMOR IMMUNITY BY AN IMMUNOMODULATOR PS-K AND COMBINED THERAPEUTIC EFFECTS OF PS-K AND CYCLOPHOSPHAMIDE ON TRANSPLANTED TUMOR IN RATS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (12) , 5176-5180
Abstract
An immunomodulator PS-K diminished the cyclophosphamide (CY)-induced suppression of specific antitumor transplantation resistance in WKA rats immunized with X-irradiated KMT-17 tumor cells when PS-K was given before treatment of CY. In the immunochemotherapy of transplanted KMT-17 tumor in WKA rats by a combination of CY and PS-K, an enhanced therapeutic effect was also observed when PS-K was given before treatment of CY, with different doses of CY and at different days of CY treatment. However, when PS-K was given just after treatment of CY, the therapeutic effect was rather diminished in comparison with the group having CY treatment alone. By means of the Winn assay, spleen cells obtained from KMT-17-bearing rats (TBR) treated with PS-K followed by CY inhibited the admixed tumor cells more strongly than did spleen cells obtained from TBR treated with CY alone. Recovery of thymus weight from the damage caused by CY was accelerated in TBR treated with PS-K followed by CY and was delayed in TBR treated with CY followed by PS-K. Diminution of CY-induced immunosuppression by PS-K possibly results in an enhanced therapeutic effect in WKA rats treated with PS-K followed by CY.