Immunological analysis of enhanced spontaneous metastasis in WKA rats following cryosurgery
Shibata, T.; Suzuki, K.; Yamashita, T.; Takeichi, N.; Mark, M.; Hosokawa, M.; Kobayashi, H.; Arisue, M.
Anticancer Research 18(4a): 2483-2486
1998
ISSN/ISBN: 0250-7005 PMID: 9703896 Document Number: 491413
We have previously reported that inhibition of antitumor immune responses and enhancement of metastatic tumor growth occurred in rats following cryosurgery of the transplantable 3-methylcholanthrene-induced rat fibrosarcoma KMT-17. In this study, to elucidate the immunological responses in rats following cryosurgery, we examined whether rat serum obtained from rats which underwent cryosurgery (c-serum) might affect the in vivo neutralizing activity of the Winn assay. In this assay, c-serum did not reduce the anti-tumor immunity, though spleen cells obtained from rats undergoing surgical excision indicated strong anti-tumor immunity as compared with cryosurgery. Thus, we examined the anti-tumor responses of spleen cells. Macrophages were obtained from the glass adherent fraction of rat spleen cells following cryosurgery and these macrophages were used for cytostatic activity against KMT-17 cells. Cytostatic activity was not reduced by cryosurgery. The spleen cells obtained from rats receiving cryosurgery were intravenously transferred into other rats that were previously immunized with 80 Gy-irradiated KMT-17 cells, and an alteration of tumor growth modulated by this adoptive cell transfusion was observed. The anti-tumor resistance of rats was diminished by the adoptive transfusion of spleen cells treated with cryosurgery, though this diminution disappeared following anti-T serum and immune complement treatment of spleen cells. These results suggest that immuno-suppression following cryosurgery may be mainly caused by suppressor T cells.