Ex vivo expansion of CD56+ cytotoxic cells from human umbilical cord blood.

Abstract

The immune-mediated effect of natural killer (NK) and cytotoxic T cells against residual tumor cells previously was shown to prevent relapse and reinduce remission after bone marrow transplantation. Human umbilical cord blood is a rich source of cytotoxic CD56+ cells including fetal NK cells (CD16(-)CD56+1) with high lytic capabilities upon activation with interleukin-2 (IL-2). Cord blood transplantations are reported to be associated with lower risk of graft-vs-host disease, which may jeopardize the graft-vs-leukemia effect. Therefore, our goal was to expand and amplify, ex vivo, cord blood-derived CD56+ cell-mediated cytotoxic activity. Cord blood-derived CD56+ cells were separated using anti-CD56 monoclonal antibody and immunomagnetic beads. The cells were expanded in the presence of irradiated feeder cells and various concentrations of IL-2. Maximal fold expansion (152 +/- 29) was achieved on day 22 by culturing the cells in the presence of irradiated autologous lymphocytes. Irradiated murine stromal cells yielded 42 +/- fourfold expansion (p < 0.05). FACS analysis at the peak of expansion revealed that the cells were 96% +/- 1% CD56+. Interferon-gamma levels significantly decreased throughout the culture period (from 1,034 +/- 34 pg/mL to 21 +/- 8 pg/mL) as did IL-6 levels (from 11,535 +/- 1,452 pg/mL to 323 +/- 161 pg/mL) whereas tumor necrosis factor-alpha levels did not change. The expanded cells manifested potent lytic capabilities against K562 and Colo-205 cell lines (70.9% +/- 2.0% and 48.2% +/- 4.0%, respectively) (n = 5) (effector-to-target ratio 25:1). Coculturing the expanded NK cells with fresh ALL blasts resulted in 85% +/- 1% inhibition of colony growth in methylcellulose (n = 2). In addition, the CD56+ expanded cells induced 44% +/- 7.5% apoptosis of K562 target cells (n = 3). It is possible to effectively expand cord blood-derived CD56+ cells, ex vivo, while maintaining their antileukemic capablilities.

• Authors: R Condiotti, Y B Zakai, V Barak, A Nagler
• Journal: Experimental hematology (Exp Hematol) Vol. 29 Issue 1 Pg. 104-13 (Jan 2001) ISSN: 0301-472X [Print] Netherlands
• PMID: 11164111 (Publication Type: Journal Article)

Chemical References

• CD56 Antigen
• Interleukin-2
• Interleukin-6
• Tumor Necrosis Factor-alpha
• Interferon-gamma

Topics

• Animals
• Apoptosis
• CD56 Antigen (analysis)
• Cell Culture Techniques (methods)
• Cell Division (drug effects)
• Cells, Cultured (drug effects)
• Coculture Techniques
• Colonic Neoplasms (pathology)
• Cytotoxicity Tests, Immunologic
• Fetal Blood (cytology)
• Flow Cytometry
• Humans
• Immunomagnetic Separation
• Immunophenotyping
• Infant, Newborn
• Interferon-gamma (metabolism)
• Interleukin-2 (pharmacology)
• Interleukin-6 (metabolism)
• K562 Cells (pathology)
• Killer Cells, Natural (chemistry, cytology, drug effects, metabolism)
• Leukemia-Lymphoma, Adult T-Cell (pathology)
• Mice
• Precursor Cell Lymphoblastic Leukemia-Lymphoma (pathology)
• Stromal Cells (cytology, radiation effects)
• Tumor Cells, Cultured
• Tumor Necrosis Factor-alpha (metabolism)