Differentiation of progressive versus regressive Rous virus-induced avian sarcomas according to tumor and infiltrating lymphocyte fine structure.
Electron microscope examination of progressing and regressing Rous virus-induced sarcomas in an inbred line of White Leghorns revealed that regressing tumors contained moderate to marked lymphocyte infiltration, frequent contact between lymphocytes and tumor cells, and extensive areas of necrosis. Lymphocytes infiltrating regressing tumors exhibited a polar accumulation of organelles at the point of contact between lymphocyte and target cell. On the other hand, progressing tumors contained low to moderate numbers of lymphocytes, infrequent lymphocyte-tumor cell interaction and less evidence of tumor cell degeneration. Lymphocytes from progressing tumors lacked the polar organization of organelles. This experimental system is offered as a means of studying the role of lymphocytes in tumor regression.
D000818:Animals; D002645:Chickens; D008214:Lymphocytes / Q000648:ultrastructure*; D009365:Neoplasm Regression, Spontaneous; D011201:Poultry Diseases / Q000473:pathology*; D001357:Sarcoma, Avian / Q000648:ultrastructure*