Scanning electron microscopic study of bovine leukemic cells.

Scanning electron microscopic observation of (i) leukemic cells in peripheral blood and tumor tissues of 11 cattle with bovine leukosis (adult form, n = 5; calf form, n = 2; and thymic form, n = 4) and (ii) peripheral lymphocytes from 2 cattle with persistent lymphocytosis and from 3 healthy cattle revealed morphologic differences of cell surface structures among various forms of bovine leukosis. These differences indicated an interrelationship of cell surface morphologic features between peripheral lymphocytes and tumor cells. Leukemic cells from cattle with the thymic and calf forms characteristically had a smooth surface. In cells from cattle with the adult form, the majority of abnormal cells in the peripheral blood, possessed numerous elongated microvilli on the cell surface, whereas tumor cells in the tissue were pleomorphic with a long villous, plicated surface or had stubby projections. Most of the peripheral lymphocytes from cattle with persistent lymphocytosis were characterized by a dense arrangement of elongated microvilli on the cell surface.