Heterotransplantation of human cell lines from Burkitt's tumors and acute leukemia into newborn rats

The heterotransplantability of 22 human cell lines was studied by intravenous inoculation into newborn rats. The cell lines included nine derived from Burkitt (African) lymphoma, one from reticulum cell sarcoma, ten from leukemia, one from infectious mononucleosis and one from a normal lymph node. All were cultivated in vitro as suspension cultures. The usual inoculum for each rat was 50 or 10 or 2 million cells. At the two higher doses four of the Burkitt tumor lines (EB‐2, EB‐3, SL1, B35M), three of the leukemia lines (SK‐L2, SK‐L5, SK‐L9), the infectious mononucleosis line C566, and the cell line from a normal lymph node (SK‐LN1) propagated and caused lethal lesions in approximately half of the recipients. Inocula containing 2 million cells of lines EB‐2 or SL1 grew in a few rats but none of the other cell lines grew at this dose. Brain, eye and kidney were the most common sites of growth. Lung, adrenal, liver, and interscapular fat pad were less frequently involved, and other tissues rarely. The results are discussed in relation to the biologic significance of heterotransplantability and differences in the tissue distribution of implants of these and previously studied human cell lines.