title: [Immunological surveillance mechanism of a rat brain tumor model--study of time-lapse changes in the concomitant immunity of peripheral blood lymphocytes by microcytotoxicity assays (author's transl)].
abstract: A rat brain tumor model was prepared by semi-stereotactically implanting 1 x 10(6) RG--C6 tumor cells (chemically induced and maintained in vitro) in the right caudate nucleus of inbred WKA rat by a new method "Soft Agar Technique" which we developed. The tumor grew at a nearly fixed rate. We measured the maximum tumor area and the whole brain area of the rat brain which were sectioned coronary in series. We regarded the percentage of the tumor area to the whole area of the same section as tumor growth index. Microcytotoxicity assays of peripheral blood lymphocytes were performed at various stages of the tumor growth. RG--C6 cells were used as target cells, and they mixed with lymphocytes by Takasugi and Klein's method. Cytotoxicity index was higher in 22 cases (80.00 +/- 16.67; tumor growth index, 0--10) than in 28 cases of the control group (67. 25 +/- 19.68) and then gradually decreased with tumor growth (Fig. 2). At last cytotoxicity index went down to 41.55 +/- 24.94 in 11 cases (tumor growth index, over 31). These observations have a strong resemblance to other animal tumor models and suggest that the rat having brain tumor intra-axially have concomitant immunity especially in the first stage of tumor bearing.
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000139:chemically induced / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D004195:Disease Models, Animal; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D009368:Neoplasm Transplantation / Q000379:methods; D009374:Neoplasms, Experimental / Q000276:immunology; D009603:Nitroso Compounds; D051381:Rats; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: D009603:Nitroso Compounds