Significant Ex-Vivo Expansion and Functional Activation of Cord Blood (CB) Natural Killer (NK) Cells with A Concomittant Significant Decrease in CB T Cells Following Stimulation with Genetically Engineered K562 Cells (K562-mb15-41BBL)

• Published in: Blood 2009-11, Vol.114 (22), p.499-499
• Main Authors: Hochberg, Jessica, Ayello, Janet, VandeVen, Carmella, Gold, Jeremy, Cairo, Evan, Zhao, Frances, Cairo, Mitchell S.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V114.22.499.499

Abstract 499 CD56+ NK subsets exhibit differential NK receptors (NKR) such as cytotoxicity profiles including killer-Ig-like receptors (KIR), C-lectin (NKG2) and natural cytotoxicity receptors (NCR) involved with tumor target recognition, which, in part, may play a role in adoptive cellular immunotherapy (ACI) for malignancies (Farag et al Blood, 2002). NK cell activation and NK mediated cytolysis is induced by triggering receptors such as NCR (i.e. NKp46), and NKG2 surface receptors like NKG2D (Moretta et al, Curr Opin in Immunol, 2004, Marcenaro et al, Eur J Immunol, 2003). The major limitations of the use of NK cells in ACI include lack of tumor recognition and/or limited numbers of viable and functionally active NK cells (Shereck/Cairo et al. PBC, 2007). To circumvent these limitations, methods to expand and activate PB NK cells by genetic reengineering have been developed (Imai/Campana et al. Blood, 2005). It has been demonstrated that PB NK cells expanded with modified K562 cells expressing membrane bound IL-15 and 4-1BBL (K562-mb15-41BBL; Imai et al Blood, 2005) are significantly increased in number and maintain heterogeneous KIR expression (Fusaki/Campana et al, BJH, 2009) .We have previously reported the ex-vivo expansion, activation and cytolytic activity of CB NK cells with a cocktail of antibody and cytokines (Ayello/Cairo et al, BBMT, 2006; Ayello/Cairo, Exp Hem, 2009, In Press). In this study, we compared CB NK expansion and activation following stimulation with genetically engineered K562 cells (K562-mb15-41BBL, generously supplied by D.Campana, St Jude's Children's Hospital, Memphis, TN) with wild-type (WT) K562 cells and NK cell characterization expressing inhibiting and activating KIRs, c-lectin, NCRs and NK cytolytic activation. Methods: Following irradiation with 100Gy, K562-mb15-41BBL or WTK562 were incubated at a 1:1 ratio with fresh CB MNCs at 37C, 5% CO2 for 7 days in RPMI-1640+10IU IL-2. NKR expression (KIR2DS4, NKG2D, NKG2A, CD94, KIR3DL1, KIR2DL2, Nkp46) and LAMP-1 (CD107a) receptor expression and NK cell phenotype (CD56 dim and bright subsets) were determined by flow cytometry. Results: On Day 0, NK cells population was 3.9±1.3%. After 7 days in culture, CB NK cells were significantly increased compared to WTK562 and media alone (72±3.9 vs 43±5.9 vs 9±2.4%, p