“…Long-term and presumably permanent lines of human lymphoid cells have been obtained from bone marrow (Benyesh-Melnick at al., 1963), lymph nodes (Trujillo et al, 1966(Trujillo et al, , 1967Ponten, 1967;Sinkovics et al, 1967), Burkitt tumors and peripheral blood (Brooke and Osgood, 1959;Pulvertaft, 1964;Epstein et al, , 1966Stewart et al, 1965;Foley et a/., 1965; Rabson et a/., 1966; Fahey et a/., 1966; Tanigaki et a/., 1966; Armstrong, 1966;Moore etal., 1967;Clarkson etal., 1967). The chain of events with three distinct phases is characteristic only of bone marrow and lymph node cell.…”