A novel v-erb-B-transformed cell-line co-expressing lymphoid and myeloid surface-markers

We have generated a novel hematopoietic cell line which co-expresses lymphoid and myeloid cell surface markers. This cell line, termed E6-2TH, was derived from thymus tissue of a mouse which developed leukemia following lethal irradiation and reconstitution with retrovirally infected bone marrow progenitor cells. Infection was effected with a recombinant murine retrovirus containing v-erb-B. The cells which grew out from the thymus tissue were initially dependent on WEHI-3B conditioned medium as a source of exogenous growth factor, but progressed in culture to become growth factor independent. Flow cytometric analysis using lineage-specific surface markers demonstrated that the initial growth factor dependent cells co-expressed myeloid and B lymphoid antigens, while the derived growth factor independent cells expressed only antigens specific to the B lymphoid lineage. This result indicates a mixed lymphoid/myeloid phenotype in this cell line and subsequent lineage specialisation during in vitro tumor progression.