Nemeth-Kellner Lymphoma Is a Valid Experimental Model in Testing Chemical Agents for Anti-Lymphoproliferative Activity*

Scheme of detection and investigation of antitumor activity of chemical substances by use of experimental murine Nemeth-Kellner lymphoma (NK/Ly) are described. It includes monitoring of growth of NK/Ly ascites by everyday weighting of animals in course of intraperitoneal application of tested substance in 24 or 48 hours after inoculation of 107 tumor cells. The inhibitory effect became distinct on the 6th-8th day of experiment, and 3 types of response were observed: 1) complete suppression of ascites development, corresponding to high antitumor activity of tested substance; 2) partial suppression of ascites growth (weak antitumor activity); 3) insignificant effect on ascites growth (lack of activity, at least towards hematoblastoses). As compared with leukemia L1210 or P388 lymphoma NK/Ly provides more distinct daily increment of body weight due to tumor growth. Clinical pattern of tumor development was supported by cytomorphological investigations of tumor cells which included: 1) cells count in ascites; 2) measuring cell dimensions and ratio of enlarged cells in a population (diameter over 17 μm in case of NK/Ly); 3) quantitative evaluation of tumor cells damage by smears count after staining with azure-eosin, bromophenol blue and hematoxylin. In case of complete suppression of ascites growth the cytological investigation was conducted by delayed application of tested agent to animals with the developed ascites. After treatment with vinblastine or doxorubicin NK/Ly cells represent a convenient object for fractionation of cell population, as demonstrated by separation of giant and small tumor cell subpopulations.