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Updated: Aug 8, 2026
Expansion, Purification, and Functional Assessment of Human Peripheral Blood NK Cells
Published on: February 3, 2011
Effect of heat-pretreatment on interleukin-2-activated killer cells for in vitro purging
1First Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan. m-tanaka@kurume.ktarn.or.jp
Objective:
Lymphokine-activated killer activity is effective in purging residual malignant cells from autologous bone marrow (BM) or leukapheresis collections for peripheral blood progenitor cells (PBPC). In this study, the effect of additional heat pretreatment on IL-2-activated cytotoxicity was examined.
Methods:
Nonadherent mononuclear cells from peripheral blood (PB), PBPC collections or BM were exposed to the desired temperature for 1 h, and successively cultured for 7 days in the presence of 1,000 units/ml of recombinant human interleukin-2 (IL-2). Cytotoxicity of IL-2-activated cells was determined by flow cytometry, using PKH-26-labelled K-562 or Raji target cells, and the cell surface antigens were also analyzed.
Results:
IL-2-activated cells from all specimens showed a distinct generation of cytotoxic activities. The activities were significantly decreased by heat at 42 degrees C, but not changed by heat pretreatment at 40 degrees C. In the surface expression of IL-2-activated cells, the increase of CD56+ cells from PB, PBPC collections and the decrease of CD28 cells from PBPC collections were shown to be significant (p < 0.05), but these changes were not found when the cells were heat-pretreated at 42 degrees C.
Discussion:
These results suggested that a tumor-killing therapeutic temperature (> or =42 degrees C) may lead to a disadvantage in posttransplantation immunity, and that this reduction of IL-2-activated cytotoxicity may partly be due to a lack of the enhancement of CD56+ cells or the reduction of CD28+ cells.
