Natural Killer T-Cells

CXCR6 is a receptor for the chemokine CXCL16, which exists as a membrane or soluble form. CXCR6 is a marker for resident memory T (TRM) cells that plays a role in immunosurveillance through their interaction with epithelial cells. The interaction of CXCR6 with CXCL16 expressed at the membrane of certain subpopulations of intratumor dendritic cells (DC) called DC3, ideally positions these CXCR6+ T cells to receive a proliferation signal from IL-15 also presented by DC3. Mice deficient in cxcr6 or blocking the interaction of CXCR6 with its ligand, experience a poorer control of tumor proliferation by CD8+ T cells, but also by NKT cells especially in the liver. Intranasal vaccination induces CXCL16 production in the lungs and is associated with infiltration by TRM expressing CXCR6, which are then required for the efficacy of anti-tumor vaccination. Therapeutically, the addition of CXCR6 to specific CAR-T cells enhances their intratumoral accumulation and prolongs survival in animal models of pancreatic, ovarian and lung cancer. Finally, CXCR6 is part of immunological signatures that predict response to immunotherapy based on anti-PD-(L)1 in various cancers. In contrast, a protumoral role of CXCR6+T cells has also been reported mainly in Non-alcoholic steatohepatitis (NASH) due to a non-antigen specific mechanism. The targeting and amplification of antigen-specific TRM expressing CXCR6 and its potential use as a biomarker of response to immunotherapy opens new perspectives in cancer treatment.

Cell-based immunotherapy has become the new-generation cancer medicine, and "off-the-shelf" cell products that can be manufactured at large scale and distributed readily to treat patients are necessary. Invariant natural killer T (iNKT) cells are ideal cell carriers for developing allogeneic cell therapy because they are powerful immune cells targeting cancers without graft-versus-host disease (GvHD) risk. However, healthy donor blood contains extremely low numbers of endogenous iNKT cells. Here, by combining hematopoietic stem cell (HSC) gene engineering and in vitro differentiation, we generate human allogeneic HSC-engineered iNKT (AlloHSC-iNKT) cells at high yield and purity; these cells closely resemble endogenous iNKT cells, effectively target tumor cells using multiple mechanisms, and exhibit high safety and low immunogenicity. These cells can be further engineered with chimeric antigen receptor (CAR) to enhance tumor targeting or/and gene edited to ablate surface human leukocyte antigen (HLA) molecules and further reduce immunogenicity. Collectively, these preclinical studies demonstrate the feasibility and cancer therapy potential of AlloHSC-iNKT cell products and lay a foundation for their translational and clinical development.

Human natural killer T cells (NKTs) are innate-like T lymphocytes increasingly used for cancer immunotherapy. Here we show that human NKTs expressing the pro-inflammatory cytokine interleukin-12 (IL-12) undergo extensive and sustained molecular and functional reprogramming. Specifically, IL-12 instructs and maintains a Th1-polarization program in NKTs in vivo without causing their functional exhaustion. Furthermore, using CD62L as a marker of memory cells in human NKTs, we observe that IL-12 maintains long-term CD62L-expressing memory NKTs in vivo. Notably, IL-12 initiates a de novo programming of memory NKTs in CD62L-negative NKTs indicating that human NKTs circulating in the peripheral blood possess an intrinsic differentiation hierarchy, and that IL-12 plays a role in promoting their differentiation to long-lived Th1-polarized memory cells. Human NKTs engineered to co-express a Chimeric Antigen Receptor (CAR) coupled with the expression of IL-12 show enhanced antitumor activity in leukemia and neuroblastoma tumor models, persist long-term in vivo and conserve the molecular signature driven by the IL-12 expression. Thus IL-12 reveals an intrinsic plasticity of peripheral human NKTs that may play a crucial role in the development of cell therapeutics.

AbstractCurrent therapies, including autologous chimeric antigen receptor (CAR) T-cell immunotherapy, fail to cure half of infants with KMT2A-rearranged acute lymphoblastic leukemia (KMT2Ar-ALL), a disease characterized by frequent central nervous system involvement, poor treatment response, early relapse, and lineage switching. More effective treatment strategies, including the availability of off-the-shelf immunotherapies, is particularly relevant in infants. PROM1/CD133 is a direct target of KMT2A-fusion oncoproteins and is expressed on leukemic cells. Allogeneic invariant natural killer T (iNKT) cells, "innately" more powerful effectors than T cells, can be deployed off-the-shelf without risk of acute graft-versus-host disease. Here, we equip iNKT cells with CD19- and/or CD133-targeting CARs, and investigate their antileukemia activity against KMT2Ar-ALL in relevant in vitro and in vivo models. Compared with monospecific counterparts and dual, bispecific CAR T cells, bispecific CD19-CD133 CAR-iNKT cells have a more potent antileukemia activity, effectively targeting both CAR antigen-high and -low leukemia. Bispecific CAR-iNKT cells eradicate medullary and, notably, leptomeningeal leukemia, and induce sustained remissions without discernible hematologic toxicity. Mechanistically, the more potent antileukemia effect of CAR-iNKT cells over CAR T cells is mediated by a pronounced CAR-dependent and CAR antigen-dependent upregulation of the innate activating receptor NKG2D on CAR-iNKT cells, and its engagement by its corresponding ligands on KMT2Ar-ALL cells. This ensures effective leukemia targeting even with downregulation of CD133 or CD19. Thus, by engaging with 2 different types of leukemia-associated antigens, that is, CAR antigens and NKG2D ligands, CAR-iNKT cells provide a powerful platform for the treatment of KMT2Ar-ALL. This approach can be readily adapted for other high-risk malignancies, including those with otherwise difficult to target leptomeningeal involvement.