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Immunologic Mechanisms of Tumor Regression in the T1699 Murine Mammary Adenocarcinoma Model

出版	Medical University of South Carolina, 1979
URL	http://books.google.com.hk/books?id=FLy9tgAACAAJ&hl=&source=gbs_api

註釋The spontaneous regression of the T1699 mammary adenocarcinoma in the syngeneic DBA/2 mouse was studied. Tumor regression appeared to be under immunological control since immunosuppressive treatment of tumor-bearing mice by thymectomy, sublethal irradiation, or by administration of the macrophage toxins silica and trypan blue, abrogated the potential for tumor regression. Immunohistological analysis of tumor sections obtained at various intervals during the growth and regression of tumors, revealed the presence of humoral antibody and effector cells, particularly macrophages in similar distributions, and phagocytosis of tumor cells was observed in these immunoglobulin-positive areas. Analysis of experiments in which tumor-bearing mice was pulsed with 3H-thymidine revealed that many phagocytosed tumor cells had incorporated this nuclear label and were thus apparently viable just prior to the time of phagocytosis. macrophages isolated from tumors were cytotoxic to the in vitro line of T1699 in the presence of serum derived from tumor-bearing animals but not in the presence of non-immune mouse serum. The removal of cells from such cytotoxicity assays at timed intervals revealed macrophages containing both intact tumor cells and tumor cells at various stages of degeneration. Furthermore the decrease in the number of free tumor cells was paralleled by increased numbers of phagocytosed tumor cells suggesting that free tumor cells were removed by phagocytosis. The data obtained both in vitro and in vitro, support the hypothesis that one important mechanism of tumor regression in the T1699 tumor system is mediated through antibody-dependent phagocytosis of tumor cells by macrophages.