Assay of lymphokine-activated killer activity generated from bone marrow
cells of children with acute lymphoblastic leukemia
MX Zhou, HW Findley , R Davis and AH Ragab
Division of Pediatric Hematology/Oncology, Emory University, Atlanta, GA
30322.
We recently reported that low molecular weight B-cell growth factor
(LMW-BCGF) plus recombinant interleukin-2 (rIL-2) synergistically induced
lymphokine-activated killer (LAK) activity from the bone marrow (BM) cells
of children with acute lymphoblastic leukemia (ALL). The kinetics of cell
growth, antigenic phenotype, and lytic activity of the generated effector
cells were further analyzed in this study. BM cells from ALL patients with
active disease and in complete remission (CR) were cultured with a
combination of LMW-BCGF and rIL-2. Monoclonal antibodies (anti-CD3 and
anti-Leu 19) and immunomagnetic beads were used to separate LAK cells into
three subsets: CD3+/Leu 19-, CD3+/Leu 19+, and CD3-/Leu 19+. Cytotoxicity
assays with different subsets were performed versus K562, Raji, and
autologous leukemic cells, using a 3- hour 51Cr release test. There was a
significant cell expansion of 54- fold (mean value) for CD3+ cells and
15-fold for Leu 19+ cells in culture with LMW-BCGF plus rIL-2 for 7 to 14
days, whereas no cell expansion was observed in culture with rIL-2 alone.
Although NK activity (K562) was generated from leukemic BM cells in culture
with rIL-2 alone, it is only about one third of that generated in culture
with rIL-2 plus LMW-BCGF. Analysis of lytic activity of cells generated in
the latter cultures demonstrated that CD3-/Leu 19+ cells expressed highest
lytic activity against NK-sensitive K562 cells as well as against
NK-resistant Raji cells. CD3+/Leu 19+ cells showed median cytotoxicity, and
CD3+Leu 19- cells mediated only minimal cytotoxic activity. Also, lytic
activity of CD3-/Leu 19+ cells against autologous leukemic blasts was noted
in patients with active disease. Our results demonstrate that LAK activity
generated from BM cells by LMW-BCGF and r- IL2 is mediated mainly by two
types of Leu 19+ cells: CD3-/Leu 19+ NK cells and CD3-/Leu 19+ T cells.
Although CD3+ T cells (both Leu 19+ and Leu 19-) mediated less antitumor
cytotoxicity than CD3-/Leu 19+ cells, the former cells were the major
expanding cell population in culture with LMW-BCGF and rIL-2. The new
culture system may be effective in generation of cells with LAK activity
for therapeutic use.
Volume 75,
Issue 1,
pp. 160-165,
01/01/1990
Copyright © 1990 by The American Society of Hematology
