Establishment of a hemopoietic stimulating factor producing murine leukemia cell lines: pathogenesis of granulocytosis in L8313 bearing mice.

Thy 1.2+ cells of L8313 leukemia bearing mice were previously shown to produce granulocyte macrophage colony stimulating activity (GM-CSA) and interleukin-3 (IL-3). Cell lines with the Thy 1.2+ phenotype were established from spleen cells of the leukemic mice, and were designated STIL-3 C5 and STIL-3 D10. They produced and released GM-CSA and IL-3 activities in culture supernatant. C5 cells were phenotypically Thy 1.2+ and Lyt 2.1+ with rearrangement of the T-cell receptor beta chain gene also being identified. D10 was Thy 1.2+ and L3T4+ with T-cell receptor beta chain gene rearrangement not detectable. Since the same sized rearranged bands were observed between C5 and L8313 leukemic mouse spleen cells, it is indicated that C5 cells are derived from the leukemic cells. Inoculation of these cells into mice induced granulocytosis. These results indicated that L8313, which was thought to be a "granulocytic leukemia", is actually a T-cell leukemia, whose granulocytosis is a leukemoid reaction induced by normal hemopoietic cells responding to the hemopoietic stimulating factors, GM-CSA and IL-3, produced by the leukemic T cells. Thus, L8313 should be known as a T-cell leukemia associated with granulocytosis.