Ultrastructural, cell membrane, and cytogenetic characteristics of B-cell leukemia, a murine model of chronic lymphocytic leukemia.

A murine model of a spontaneous, transplantable BALB/c B-cell leukemia (BCL1) is described. Extreme leukemia and splenomegaly develop in H-2d-compatible recipients of tumor cells. Tumor cells are medium to large lymphocytes that can be transformed into plasmacytoid cells following in vitro stimulation with lipopolysaccharide. Karyotypic analysis of transformed tumor cells reveals 36 chromosomes with several monosomies and 7 markers chromosomes. The ultrastructure of the tumor cells was studied using transmission and scanning electron microscopy. Although the appearance of tumor cells seems normal by morphological criteria, an impaired capping ability was documented using the fluorescein-conjugated concanavalin A-binding test. Impaired capping ability was documented before leukemia was overt as early as 1 to 3 days following inoculation of tumor cells. The B-cell leukemia (BCL1) provides a useful murine model for the study of various aspects of human bone marrow-derived malignant disorders.