Surface modification of T-lymphocytes observed during rosetting.

Scanning electron microscopy has been used to characterize alterations of lymphocyte surface topology that occur on contact with erythrocytes during the rosetting reaction. Molt-4 cells, a line of leukemic human lymphocytes, defined as T-cells through their ability to form rosettes with sheep erythrocytes, were used for this. Unreacted Molt-4 cells exhibit surfaces that are virtually smooth and carry few microvilli. In contrast, Molt-4 cells in rosettes display a time-dependent modification of surface topology, characterized by the emergence of numerous, long microvilli, particularly in areas of red cell contact.