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Cytotoxic functions and susceptibility to apoptosis of human CD56 bright NK cells differentiated in vitro from CD34 + hematopoietic progenitors
Author(s) -
Zamai Loris,
Del Zotto Genny,
Buccella Flavia,
Galeotti Laura,
Caico Barbara,
Luchetti Francesca,
Papa Stefano
Publication year - 2012
Publication title -
cytometry part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.316
H-Index - 90
eISSN - 1552-4930
pISSN - 1552-4922
DOI - 10.1002/cyto.a.22025
Subject(s) - perforin , granzyme , cytotoxic t cell , granzyme b , interleukin 12 , interleukin 21 , haematopoiesis , biology , progenitor cell , microbiology and biotechnology , cd34 , in vitro , cancer research , stem cell , immunology , biochemistry
Cytotoxic functions and susceptibility to apoptosis are crucial aspects of NK cells suitable to counter cancer after infusion in oncologic patients. To test the feasibility and the usefulness of infusing in vitro generated NK cells, these two features were investigated in NK cells developed in vitro from CD34 + hematopoietic progenitors. Purified CD34 + cells were cultured for 15–30 days with FLT‐3 ligand (FLT3‐L) and IL‐15 with or without IL‐21. To induce terminal differentiation, NK cells were cultured for further 15 days with IL‐15, IL‐21, or their combination. A CD56 dim /CD16 + NK subset, expressing high level of perforin, granzymes, and LFA‐1, appeared early in cultures with FLT3‐L, IL‐15, and IL‐21, but it quickly died, indicating its predisposition to apoptosis. On the contrary, CD56 bright NK cells generated after 30 days of culture with FLT3‐L plus IL‐15 did not show a considerable apoptosis, nevertheless only a subset of these cells expressed granzyme‐B, perforin, LFA‐1, and CD94‐CD159a heterodimer, indicating a functional immaturity. Interestingly, further 15 days of culture with IL‐21 plus IL‐15 did not induce the generation of CD56 dim cells from the CD56 bright subset and actually inhibited IL‐15‐induced maturation/activation of this latter subset. In fact, IL‐15 alone upregulated granzyme‐B, TRAIL, Fas ligand, CD94‐CD159a, LFA‐1, CD16, KIRs, and TRAIL‐R2 on CD56 bright NK cells. Our results suggest that during differentiation CD56 bright NK cells, similarly to mature activated NK cells, become highly cytotoxic and are relatively resistant to apoptosis induced by TNF family members. © 2012 International Society for Advancement of Cytometry.