Cellular Adjuvant Properties, Direct Cytotoxicity of Re-differentiated Vα24 Invariant NKT-like Cells from Human Induced Pluripotent Stem Cells

摘要

Highlights ? Human iNKT cell-derived iPSCs have differentiated into Vα24 iNKT-like cells in?vitro ? Re-differentiated iNKT-like (Re-iNKT) cells have functionally recovered properties ? Re-iNKT cells function as an adjuvant to activate antigen-specific CTLs and NK cells ? Re-iNKT cells exert cytotoxic activity via NKG2D- and DNAM-1-dependent mechanism Summary Vα24 invariant natural killer T (iNKT) cells are a subset of T lymphocytes implicated in the regulation of broad immune responses. They recognize lipid antigens presented by CD1d on antigen-presenting cells and induce both innate and adaptive immune responses, which enhance effective immunity against cancer. Conversely, reduced iNKT cell numbers and function have been observed in many patients with cancer. To recover these numbers, we reprogrammed human iNKT cells to pluripotency and then re-differentiated them into regenerated iNKT cells in?vitro through an IL-7/IL-15-based optimized cytokine combination. The re-differentiated iNKT cells showed proliferation and IFN-γ production in response to α-galactosylceramide, induced dendritic cell maturation and downstream activation of both cytotoxic T lymphocytes and NK cells, and exhibited NKG2D- and DNAM-1-mediated NK cell-like cytotoxicity against cancer cell lines. The immunological features of re-differentiated iNKT cells and their unlimited availability from induced pluripotent stem cells offer a potentially effective immunotherapy against cancer. Graphical Abstract Figure options Download full-size image Download as PowerPoint slide prs.rt("abs_end"); Introduction Cytotoxic T lymphocytes (CTLs) play a crucial role in the eradication of cancer cells by precisely recognizing them via tumor antigen-specific T?cell receptors (TCRs) in a peptide-dependent, human leukocyte antigen (HLA)-restricted manner ( Maus et?al., 2014 ). Sometimes, however, cancer cells can proliferate due to absent or dysfunctional CTLs, thus creating demand for immunotherapies. We and another group recently reported the unlimited production of target antigen-specific human CD8+ T lymphocytes from induced pluripotent stem cells (iPSCs) ( Nishimura et?al., 2013 and Vizcardo et?al., 2013 ). This technology has the potential to overcome two important problems currently facing T?cell immunotherapies: a shortage of tumor antigen-specific T?cells and their exhaustion induced by continuous TCR stimulation and overproliferation ( Schietinger and Greenberg, 2014 ). However, other problems in T?cell immunotherapies must also be overcome. One example is the emergence of tumor escape from antigen-specific monoclonal CTLs due to tumor immune-editing involving tumor antigen mutagenesis or HLA depression ( Schreiber et?al., 2011 ). Another problem is local immunosuppression in the tumor microenvironment by instigated immune cells, which supports tumor growth and inhibits CTL activities ( Mittal et?al., 2014 , Motz and Coukos, 2013 and Noy and Pollard, 2014 ). A good approach to overcome these problems would be combination therapy using a cellular adjuvant, i.e., invariant natural killer T (iNKT) cells, as iNKT cells exert helper functions to induce antigen-specific polyclonal CTLs ( Cerundolo et?al., 2009 ), improve the immunosuppressive milieu ( De Santo et?al., 2010 ), and maintain memory CD8+ T?cells ( Hong et?al., 2009 ).