Ultrastructural expression of virus-like particles in human leukaemic cells growing in vitro

Viral-like characteristics of particle aggregates in a lymphoblastic cell line

A lymphoblastic cell line (K45) established from a child with acute lymphoblastic leukemia (ALL) is characterized by a profusion of intracytoplasmic particle aggregates (PA) similar in morphology to those occurring in fresh childhood ALL cells. The PA in K45 cells were examined for morphology and capacity for nucleic acid synthesis to test the hypothesis that they are identical to those in fresh ALL cells, and also to identify characteristics which might distinguish PA from cell organelles and which might determine if they are viral-like. In contrast to cell organelles, the PA in both K45 and ALL cells were found to be characterized by a localized thickening of the particle wall. Furthermore, autoradiography of K45 cells showed uptake by PA of 3H uridine rather than 3H thymidine indicating an RNA composition. The presence of PA in profusion was associated with, but preceded necrotic death of K45 cells. These combined features suggest that the PA in K45 and in ALL cells are identical, that they are distinct from cell organelles, are not formed as a consequence of the initiation of cell death and that, while their exact nature remains unknown, a viral origin cannot be excluded.

Establishment and characterization of a new permanent cell line (GDM-1) from a patient with myelomonoblastic leukemia

The GDM-1 permanent cell line was established from the peripheral blood of a patient with a Philadelphia chromosome negative myeloproliferative disorder, after transformation to acute myelomonoblastic leukemia. The GDM-1 cells exhibited the same characteristics as those isolated from the peripheral blood of the patient prior to death: cells contained non-specific esterase sensitive to fluoride, myeloperoxidase, lysozyme (muramidase), and exhibited both Fc and complement (C3) receptors but lacked B- and T-cell surface markers including T-associated antigens. E-rosetting capacity, surface and intracytoplasmic immunoglobulins and EBV determined nuclear antigen (EBNA). The GDM-1 cells bore the 1a receptor and the myeloid leukemia antigen (M-1). The karyotype of the cultured leukemic cells showed the same specific chromosomal abnormalities present in the monoblasts obtained from the peripheral blood prior to death, indicating that the cell line was derived from the original leukemic cells.

Characteristics of a cell line established from a child with familial acute myeloid leukaemia

The properties of an unusual new cell line from a child with acute myeloid leukaemia (AML) is described. The patient, his mother and grandmother all died within 2 years of AML. Karyotypic analysis suggests that the cells which grow in vitro represent a proliferation of the child's leukaemic cells. The presence of myeloid alkaline phosphatase in these cells suggests that they represent a proliferation of malignant myeloblasts. During the first year in culture a significant percentage of the cells formed E-rosettes, but the cells failed to react with monoclonal anti-T-cell antibodies. The cells are SmIg, Fc, C3 and EBNA negative. Ultrastructural examination of the cells revealed cytoplasmic inclusion bodies which contained virus-like particles. These inclusion bodies and particles were similar to those observed by us in two other human leukaemic cell lines and not unlike those in fresh human leukaemic cells, as reported by others.