[Electron microscopic analysis of lymphocyte fibrillar elements during the redistribution of surface receptors]

Filaments 5 nm thick, located throughout the cytoplasm mainly along the surface, are observed in intact lymphocytes. In the control glycerinized lymphocytes, besides the above filaments aggregations of filaments nearly 3 nm in diameter were found. After the treatment of cells by antimurine serum or ferritin-conjugated concanavalin A, some fibrillar structures are observed mainly in the cap region in the form of filaments 5-6 nm of thickness, radially directed towards the plasma membrane. After glycerinization, three types of filaments are observed being, respectively, near 3, 5-6 and almost 8 nm in diameter. Two latter types of filaments are decorated by S1-myosine fragments which indicates their actine nature. Differences in the character and distribution of myofibrils in the cytoplasm of intact cells and cells with caps may witness in favour of their involvement in the processes associated with redistribution of surface receptors.