We have established a cell line (ICI 101) from blood taken from a patient with lymphoblastic leukaemia and stored at -70°C. A comparative morphological, virological and immunological study of this line and the fresh cells have been made. Virus particles, resembling murine leukaemia viruses, were detected in the fresh cells and found in samples from the cultures. The antigenic activity of the lymphoblasts, as demonstrated by immune adherence with the patient's serum, was present in the cultured cells. The antigenicity of the cultured cells was greater with the fresh cells (in immune adherence and fluorescence). This phenomenon is under study. This lymphoblastic line (ICI 101) which has retained its virus content and antigenic marker, is an excellent material for the study of human leukaemia. Finally, the isolation of this line from frozen cells shows that freezing of the original cells to -70°C is not an obstacle to the establishment of continuous cell lines. © 1969.
