Characterization of Epstein-Barr virus-carrying cell lines established from chronic lymphocytic leukemia

Attempts were made to establish lymphoid cell lines from the cultured peripheral blood lymphocytes of six patients with chronic lymphocytic leukemia. In only one case was cell growth obtained following the addition of exogenous transforming Epstein-Barr virus, and those cell cultures proved not to have acquired the ability to proliferate permanently. In the same case, cell lines were established spontaneously from the peripheral blood without addition of Epstein-Barr virus. The cells which grew spontaneously were large, were occasionally weakly surface adherent, and grew in suspension as loose clumps or as single cells. They were negative for surface immunoglobulins and spontaneous rosette formation with sheep erythrocytes and positive for intracytoplasmic immunoglobulins (Fc and C3 receptors). At an early passage, the spontaneous lines had an aneuploid karyotype with some triploid and some tetraploid cells. Structural chromosomal aberrations include a 14q+. Electron microscopy of the chronic lymphocytic leukemia lines revealed relatively smooth surfaces with numerous mitochondria, widespread vacuolization, and numerous unusual "myelin" figures. Five to 10% of the cells were phagocytic as detected by internalization of latex particles; however, they were Epstein-Barr nuclear antigen positive. The nature of these cells and their possible relationship to the etiology of chronic lymphocytic leukemia are discussed.