Cytokine-induced Memory-like NK Research Articles

Cytokine-induced memory-like (CIML) NK cells and association with circulating immune microenvironment.

e18042 Background: Cytokine-induced memory-like (CIML) NK cells are attractive for adoptive cell therapeutic approaches due to their key characteristics which include anti-tumor responses, prolonged proliferation and persistence in vivo. Several NK cell subsets have been reported in human and mice, but their heterogeneity and trajectories in human peripheral blood remains poorly characterized. We aimed to evaluate the developmental trajectories and prognosis outcomes of several CIML NK subsets between HPV+ and HPV- HNSC patients. Methods: A publicly available scRNA-seq dataset (only CD45+PBMC data sets were used) (Kürten et al., 2021) was obtained and stratified by two definitions of CIML NKs: (1) increased granzyme B mRNA expression and (2) preactivated with iterleukin-12 (IL-12), IL-15 and IL-18. Single-cell analysis was performed, followed by sub-clustering of NK populations. Results: 4,794 NK cells from 6 HPV+ and 11 HPV- HNSC patients were analyzed in our study. Expression profiles showed that these NK cells were CD56dimCD16+CD57-NKs. Further investigation showed that these cell populations exhibit a cytokine-induced memory-like phenotype, including increased granzyme B mRNA and preactivated with IL-12, IL-15 and IL-18. Transcriptomic profiles demonstrated that CIML NK cells can be classified into three subsets, including Bl1, Bl2, and Bl3, where Bl1 and Bl3 were found to be consistent with the previous studies, Bl2 was a newly identified NK cluster in this study. Pseudotime analyses suggested that CIML NK cells transitioned from Bl3 (is in cytolytic state) to Bl2, and then (maintains intermediate cell states) to Bl1 (supports cytotoxic activity), regardless of HPV status. There were 20, 60, and 26 Up-regulated genes in Bl, Bl2, and Bl3 in HPV+ patient compared to HPV- patients, respectively. Biocarta pathway analyses showed that NK cell pathway was highly enriched in all NK subsets from HPV+ patients, instead of HPV- patients, indicating a developmental independent characteristic. Survival analyses showed poor prognosis outcomes for high expressed CIML NK signatures in no matter HPV+ or HPV- patients. Conclusions: We investigated CIML NK cells in human peripheral blood and found that Bl1, Bl2, and Bl3 NK clusters showing the developmental patterns of increased cytotoxicity independent of HPV status. The Bl2 is a novel NK cell cluster which presents intermediate cell states. The cluster signatures were correlated with poor clinical outcomes, highlighting its’ potential clinical values for CIML NK-targeted immunotherapies.

Abstract SY30-02: NK cells remember: Engineering NK cell memory-like responses for cancer immunotherapy

Abstract Natural killer (NK) cells are innate lymphoid cells that protect against infection and mediate anti-tumor immune responses. NK cell immunotherapy is a promising cellular therapy approach for leukemia, lymphoma, and other cancers. Multiple laboratories have advanced our understanding of innate NK cell memory and memory-like responses over the past decade, with a unifying definition of enhanced response to re-stimulation after an initial activation event. We identified that human cytokine-induced memory-like (memory) NK cells differentiate after a brief activation with IL-12, IL-15, and IL-18 and mediate enhanced responses against leukemia and other cancer targets. Pre-clinical studies have demonstrated their enhanced anti-tumor potential in vitro, and in vivo in syngeneic murine models and human xenografts. We translated this concept into a first-in-human clinical trial that demonstrated safe adoptive transfer of donor memory NK cells for patients with relapsed or refractory acute myeloid leukemia (AML) resulting in complete remissions. Correlative mass cytometry from this phase 1 study revealed the memory NK cell multidimensional phenotype and identified NKG2A as a major checkpoint for memory NK cell response to AML. Additional clinical trials of donor memory NK cells the HCT setting have demonstrated safety and anti-leukemia activity the immune compatible setting and has provided insights into persistence. Memory NK cells functionally persist for more than 60 days with a unique multidimensional phenotype in two clinical trials in leukemia patients. Further, CITE-seq single cell profiling reveals a unique memory NK cell transcriptomic signature. We have also developed approaches to gene edit and engineer memory-like NK cells with chimeric antigen receptors, expanding the spectrum of cancers for memory-like NK cellular therapy. CAR memory NK cells exhibit enhanced responses, compared with CAR conventional NK cells. Further, pairing with tumor targeting monoclonal antibodies can result in CAR-like responses via CD16/FcγRIIIa, providing additional activating signals that direct memory NK cell response. These studies identify a promising memory NK cell platform for cancer immunotherapy and highlight the importance of correlative studies during clinical trials to advance our understanding of human immunology. Citation Format: Todd A. Fehniger. NK cells remember: Engineering NK cell memory-like responses for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr SY30-02.

A first-in-class ex vivo combination between cytokine-induced memory like (CIML) NK cells and a CD38 targeting antibody recruiting molecule (ARM) as a novel approach to target NK cells without cellular engineering for the treatment of multiple myeloma.

8523 Background: Cytokine-induced memory-like (CIML) NK cells differentiate after a brief preactivation with interleukin-12 (IL-12), IL-15, and IL-18 and exhibit enhanced responses to cytokine or activating receptor restimulation for several weeks to months. Antibody Recruiting Molecules (ARM) are bifunctional molecules that simultaneously bind a given tumor marker and engage endogenous IgG antibodies, therefore binding and activating NK cells via their FcR and targeting them to kill tumors cells. A first in class therapy that has the potential to improve the activity of CIML NK cells by combining them with KP1237, a CD38-ARM is presented for the treatment of newly diagnosed multiple myeloma (MM) patients who are minimal residual disease positive (MRD+) and eligible for autologous stem cell transplant (ASCT). Methods: Specific killing of CD38 expressing MOLP-8 cells by CIML NK cells alone or in combination with KP1237 was measured. Additionally, NK and CIML NK cells from healthy volunteers and MM patients at various stages of the disease were tested for activity against autologous and allogeneic tumor cell targets. In these experiments, surface phenotype and activation status of NK cells were determined. Results: A statistically significant increase in specific killing was observed when KP1237 was used in combination with CIML NK cells in an ADCC assay against CD38 expressing MOLP-8 (p = 0.0105, mean 61.8 ± SD 9.1 and mean 83.7 ± SD 13.58 for CIML NK alone and CIML NK+KP1237, respectively). This effect was accompanied by an increase in plasma membrane retention of CD107a. Surface phenotype of NK and CIML NK cells from healthy volunteers and MM patients was compared since the functional activity of NK cells from such patients is debated. We report surface expression of CD56, CD16, CD57, NKG2D, Nkp44, Nkp46, CD107a, KIR2DL2/3/DS2, and CD69 as well as frequencies of CD57hi CD56+ mature versus CD57lo CD56+ immature NK cell subsets. Further, autologous CIML NK cells + KP1237 exhibit cytotoxicity towards patient plasma cells. Conclusions: The activity of CIML NK cells towards CD38 expressing MM target cells is improved by the addition of KP1237 avoiding the need for cellular engineering with chimeric antigen receptors. This led to the development of the combination drug product consisting of patient autologous CIML NK cells, KP1237 and IVIG. Clinical development is under way for (MRD+) MM patients eligible for ASCT.

Human Cytokine-Induced Memory-Like (CIML) NK Cells Exhibit Potent Anti-Leukemia Cytotoxicity and Maintain Memory-Like Functionality After Adoptive Transfer Into Immunodeficient NOD-SCID-Gc-/- (NSG) Mice

Background Allogeneic NK cells are anti-leukemia immune effector lymphocytes, with evidence of activity in patients in adoptive transfer clinical studies. What is the optimal approach to prepare allogeneic NK cells for maximal effector function remains an open question for adoptive NK cell therapy. Recently described cytokine-induced memory-like (CIML) NK cells are generated following a brief (16 hour) pre-activation with a combination of IL-12+IL-15+IL-18 in both mice and humans. Following weeks or months of rest, CIML NK cells exhibit an enhanced recall IFN-g response when restimulated with K562 cells or cytokines. However, their anti-leukemic cytotoxic activity and identification of key supporting cytokines for survival and sustained functionality have not been reported. We hypothesized that CIML NK cells may have enhanced effector function against AML, providing a potential rationale for future clinical studies of CIML NK cells in AML patients. To test this hypothesis we investigated the CIML NK cell response to myeloid leukemia, including primary AML blasts, and evaluated their function following transfer into NSG mice. Methods Normal human donor NK cells (>95% purity) were cultured with low dose (1 ng/mL) IL-15 alone (control) or pre-activated with IL-12 (10 ng/ml) + IL-15 (1 ng/ml) + IL-18 (50 ng/ml) for 16 hours. After washing, the cells were cultured for 7 days in low dose IL-15 (to support survival). Following this prolonged rest period in vitro, NK cell responses were assessed after 6-hour re-stimulation with K562 leukemia cells or primary AML blasts. NK cell functional responses assessed include IFN-g production and cytotoxicity (using flow based killing assays). For adoptive transfer experiments, 5-8 x 106 human CIML NK cells or control cells were injected into sub-lethally irradiated NSG mice, and assessed for persistence, expansion and function of the adoptively transferred CIML NK or control NK cell. Additional experiments included evaluating CIML NK cells for cytokine receptor expression and effector proteins after the 7 day rest period. Results As described previously, CIML NK cells had a significantly increased IFN-g response to K562 leukemia cells (15.5 ± 3% vs. 7 ± 1%, P=0.03). CIML NK cells also exhibited a more potent IFN-g response to primary blasts from untreated, newly diagnosed AML patients (N=4 AML samples, P< 0.0001). Further, CIML NK cells demonstrated a significantly greater cytotoxic response, compared to control NK cells, upon co-incubation with K562 leukemia cells (Figure 1). Consistent with this enhanced cytotoxicity, CIML NK cells had significantly increased expression of granzyme A (P=0.005) and granzyme B (P=0.006) proteins. Further, we noted a marked induction of CD25 (IL-2Ra) after IL-12+IL-15+IL-18 pre-activation, which via the IL-2Rabg resulted in enhanced functional responses to picomolar concentrations of IL-2. This included enhanced cytotoxicity against leukemia cells, IFN-g production in response to co-stimulation with IL-12, and proliferation. To assess persistence and expansion upon adoptive transfer, NSG mice were injected with control or CIML NK cells. After 7 days (during which 75,000IU of IL-2 was injected qOD) there was a preferential expansion of the CIML NK cells in blood (11±2.6 vs. 5±1.3, P=0.01) and bone marrow (0.6±0.14 vs. 0.21±0.06, P= 0.03) in these mice as assessed by the ratio of human to mouse CD45 positive cells. Further, CIML NK cells supported in vivo in NSG mice exhibited enhanced IFN-g responses upon re-stimulation with K562 leukemia cells (10±1.5% vs. 2.5±1% IFN-g positive, P= 0.03) or IL-12+IL-15 (15±2% vs. 2±0.5%, P= 0.001). Conclusions Brief (16 hour) pre-activation with a combination of IL-12+IL-15+IL-18 results in the generation of CIML NK cells that have an enhanced IFN-g and cytotoxic response to K562 leukemia cells and primary allogeneic AML blasts. Further, CD25 is induced on CIML NK cells, which in the context of the high affinity IL-2Rabg confers selective responsiveness to low concentrations of IL-2 for proliferation, enhanced cytotoxicity, and enhanced IFN-g production. CIML NK cells may develop in vivo in NSG xenografts, and CIML NK cells appear to be selectively supported by exogenous low dose IL-2 in this context. These pre-clinical data support CIML NK cells as a novel optimization approach for NK cell adoptive immunotherapy. Disclosures: No relevant conflicts of interest to declare.