AUTOCRINE IL-2-DEPENDENT GROWTH OF A NEWLY ESTABLISHED CD3(-), CD56(+), CD57(+), J(H)(-), TCR-BETA(-), TCR-GAMMA(-) LEUKEMIA-CELL LINE (NOI-90)(), CD16()

Leukemic cells from a 45-year-old male patient with a CD3(+), CD56(+), CD57(+), CD7(+) acute lymphoblastic leukemia were cultured in vitro i n the absence of any added growth factor for up to 6 years and a conti nuous lymphoblastoid cell line (NOI-90) was established. NOI-90 cells have the same phenotype and karyotype as initial leukemic cells. South ern blot of DNA from NOI-90 cells showed that TCR beta, TCR gamma, and J(H) were in germ line. Two and 25% of NOI-90 cells were positive whe n stained with the IOT14 and 7G7/B6 moAbs, which recognize the CD25 mo lecule (IL-2R alpha chain); moreover, 4% and 13% of the cells were pos itive when stained with the TU-27 and mik beta 3 moAbs which recognize the CD122 molecule (IL-PR beta chain). Equilibrium binding experiment s with radiolabelled IL-2 revealed the presence of a small number of h igh affinity IL-2R on both fresh and continuously growing cells. Media conditioned by NOI-90 cells could induce proliferation of an Il-2-dep endent cell line and this IL-2 activity could be detected by a sensiti ve immunoenzymatic assay using antibodies recognizing distinct epitope s of IL-2. Moreover, IL-2 activity could be adsorbed by immunoaffinity on anti-ii-a polyclonal purified IgG and the retained molecule displa yed a m.w. of 14.5 kDa in SDS-PAGE. In addition, IL-2 immunoreactive m olecules could be revealed in the cytoplasm of the cells. Finally, IL- 2 fixed on the cell membrane could be detected by indirect immunofluor escence. Although added IL-2 could not induce cell proliferation, mono clonal antibodies against CD25, CD122 and IL-2 could specifically inhi bit spontaneous cell proliferation in a dose-dependent manner. NOI-90 cells failed to demonstrate any cytotoxic activity against the K-562, Raji or Daudi cells. These findings indicate that NOI-90 cells are of non-T, non-B, origin lacking NK activity but proliferate under an auto crine pathway which involves, at least partly, the IL-2/IL-2R system.