Natural Killer Function Research Articles

Toll-like receptor 8 agonists improve NK-cell function primarily targeting CD56brightCD16− subset

BackgroundToll-like receptors (TLRs) are pattern-recognition sensors mainly expressed in innate immune cells that directly recognize conserved pathogen structures (pathogen-associated molecular patterns-PAMPs). Natural killer (NK) cells have been described to express...

Natural killer cells in liver transplantation: Can we harness the power of the immune checkpoint to promote tolerance?

The roles that natural killer (NK) cells play in liver disease and transplantation remain ill‐defined. Reports on the matter are often contradictory, and the mechanisms elucidated are complex and dependent on the context of the model tested. Moreover, NK cell attributes, such as receptor protein expression and function differ among species, make study of primate or rodent transplant models challenging. Recent insights into NK function and NK‐mediated therapy in the context of cancer therapy may prove applicable to transplantation. Of specific interest are immune checkpoint molecules and the mechanisms by which they modulate NK cells in the tumor micro‐environment. In this review, we summarize NK cell populations in the peripheral blood and liver, and we explore the data regarding the expression and function of immune checkpoint molecules on NK cells. We also hypothesize about the roles they could play in liver transplantation and discuss how they might be harnessed therapeutically in transplant sciences.

Advancement of chimeric antigen receptor-natural killer cells targeting hepatocellular carcinoma.

With the advance of genome engineering technology, chimeric antigen receptors (CARs)-based immunotherapy has become an emerging therapeutic strategy for tumors. Although initially designed for T cells in tumor immunotherapy, CARs have been exploited to modify the function of natural killer (NK) cells against a variety of tumors, including hepatocellular carcinoma (HCC). CAR-NK cells have the potential to sufficiently kill tumor antigen-expressing HCC cells, independent of major histocompatibility complex matching or prior priming. In this review, we summarize the recent advances in genetic engineering of CAR-NK cells against HCC and discuss the current challenges and prospects of CAR-NK cells as a revolutionary cellular immunotherapy against HCC.

Migration, Distribution, and Safety Evaluation of Specific Phenotypic and Functional Mouse Spleen-Derived Invariant Natural Killer T2 Cells after Adoptive Infusion

Herein, the migration distribution and safety of specific phenotypic and functionally identified spleen-derived invariant natural killer T2 (iNKT2) cells after adoptive infusion in mice were studied. The proliferation and differentiation of iNKT cells were induced by intraperitoneal injection of α-galactosylceramide (α-GalCer) in vivo. Mouse spleens were isolated in a sterile environment. iNKT cells were isolated by magnetic-activated cell sorting columns (MS columns). Cytometric bead array (CBA) assay was used to detect cytokine secretion in the supernatant stimulated by iNKT cells. The basic life status of the mice was observed, and systematic quantitative scoring was conducted after injecting spleen-derived iNKT cells through the tail vein. An in vivo imaging system was used to trace the migration and distribution of iNKT cells in DBA mice. The percentage of the iNKT2 subgroup was the highest in 3 days after intraperitoneal injection of α-GalCer, and iNKT2 subsets accounted for more than 92% after separation and purification by magnetic-activated cell sorting (MACS). Anti-inflammatory cytokine IL-4 was mainly found in the supernatant of cell cultures. The adoptive infusion of iNKT cells into healthy mice resulted in no significant change in the basic life status of mice compared with the noninjected group. iNKT cells were detected in the lung, spleen, and liver, but no fluorescence was detected in lymph nodes and thymus. After dissecting the mice, it was found that there were no significant abnormalities in the relevant immune organs, brain, heart, kidney, lung, and other organs. Intraperitoneal injection of α-GalCer results in a large number of iNKT2 cells, mainly secreting anti-inflammatory cytokine IL-4, from the spleen of mice. After adoptive infusion, the iNKT2 cells mainly settled in the liver and spleen of mice with a satisfactory safety profile.

Determining the relevance of HLA/KIR matching/mismatching on kidney and liver transplantation rejection: A meta-analysis

Abstract. Batuan B, Cajayon CJ, Castro BA, Austria ML, Co DN, Ebreo SK, Clemente B, Tiongco RE. 2021. Determining the relevance of HLA/KIR matching/mismatching on kidney and liver transplantation rejection: A meta-analysis. Nusantara Bioscience 13: 211-218. The kidney and liver are solid organs commonly transplanted nowadays. However, there are cases wherein graft rejection occurs due to foreign Human Leukocyte Antigen (HLA) proteins. Furthermore, the function of Natural Killer (NK) cells and their receptors in solid organ transplantation is not yet fully elucidated. This study aims to determine the relevance of matching HLA/Killer cell Immunoglobulin-like Receptors (KIR) with kidney and liver transplantation outcomes. Articles were screened according to the inclusion and exclusion criteria provided, which garnered eight definitive studies. Next, data were tabulated using a standardized extraction form. A meta-analysis was conducted to formulate conclusions regarding significance of HLA/KIR matching and mismatching in kidney and liver transplantations. Fixed- and random-effects models were utilized to compute and establish 95% CI and pooled ORs wherein a p-value of less than 0.05 is considered significant. A combination of Chi-square based Q test and I2 statistics were used to identify heterogeneity, which was resolved with a funnel plot. In this meta-analysis, only the HLA-Bw4/KIR3DL1 combination was found significant to lower the risk of allograft rejection (OR=0.73; PA=0.009; PH=0.42). Other combinations which include HLA-C1 and KIR2DL2/3, HLA-C1 and KIR2DS2/3, HLA-C2 and KIR2DL1/DS2, and HLA-Bw4/KIR3DS1 were found to be insignificant; hence, these do not influence the allograft rejections. In conclusion, the role of HLA/KIR combinations on solid organ transplantation rejection is only significant in HLA-Bw4/KIR3DL1 interaction which is correlated with decreased odds of allograft rejection. Factors including KIR allele variations, insufficient data and journals related to the topic, and unestablished association of HLA/KIR in other organ transplantations affected the results of this meta-analysis; thus, these are recommended to be considered in future studies.

A Novel Strategy for Off-the-Shelf T Cell Therapy Which Evades Allogeneic T Cell and NK Cell Rejection

Introduction. Despite the success of autologous chimeric antigen receptor (CAR)-T cells, barriers to a more widespread use of this potentially curative therapy include manufacturing failures and the high cost of individualized production. There is a strong desire for an immediately available cell therapy option; however, development of “off-the-shelf” T cells is challenging. Alloreactive T cells from unrelated donors can cause graft versus host disease (GvHD) for which researchers have successfully used nucleases to reduce expression of the endogenous T cell receptor (TCR) in the allogeneic product. The recognition of allogeneic cells by the host is a complex issue that has not been fully solved to date. Some approaches utilize prolonged immune suppression to avoid immune rejection and increase persistence. Although showing responses in the clinic, this approach carries the risk of infections and the durability of the adoptive T cells is uncertain. Other strategies include deletion of the B2M gene to remove HLA class I molecules and avoid recognition by host CD8 T cells. However, loss of HLA class I sends a “missing-self” signal to natural killer (NK) cells, which readily eliminate B2Mnull T cells. To overcome this, researchers are exploring insertion of the non-polymorphic HLA-E gene, which can provide partial but not full protection from NK cell-mediated lysis. Because activated T cells upregulate HLA class II, rejection by alloreactive CD4 T cells should also be addressed.Methods. Here, we developed an immunologically stealth “off-the-shelf” T cell strategy by leveraging our CRISPR/Cas9 platform and proprietary sequential editing process. To solve the issue of rejection by alloreactive CD4 and CD8 T cells, we knocked out (KO) select HLA class I and class II expression with a sequential editing process. Additionally, we utilize potent TCR-α and -β constant chain (TRAC, TRBC) gRNAs that achieve >99% KO of the endogenous TCR, addressing the risk of GvHD. An AAV-mediated insertion of a CAR or TCR into the TRAC locus is used in parallel with the TRAC KO step to redirect the T cells to tumor targets of interest. Alloreactivity by CD4 and CD8 T cells, NK killing, GvHD induction and T cell function was assessed in vitro and/or in vivo.Results. By knocking out select HLA class I and class II proteins, we were able to avoid host CD4- and CD8-T cell-mediated recognition. Edited T cells were protected from host NK cells, both in vitro and in an in vivo model engrafted with functional human NK cells. TRAC edited donor T cells did not induce GvHD in an immune compromised mouse model over the 90-day evaluation period. Using our proprietary T cell engineering process, we successfully generated allogeneic T cells with sequential KOs and insertion of a tumor-specific TCR or CAR with high yield. Importantly, these allogeneic T cells had comparable functional activity to their autologous T cell counterparts in in vitro assays (tumor cell killing and cytokine release) as well as in vivo tumor models. With a relatively small bank of donors, we can provide an “off-the-shelf” CAR or TCR-T cell solution for a large proportion of the population.Conclusions. We have successfully developed a differentiated “off-the-shelf” approach, which is expected to be safe and cost-effective. It is designed to provide long-term persistence without the need for an immune suppressive regimen. This promising strategy is being applied to our T cell immuno-oncology and autoimmune research candidates. DisclosuresZhang: Intellia Therapeutics: Current Employment. Goel: Intellia Therapeutics: Current Employment. Prodeus: Intellia Therapeutics: Current Employment. Jetley: Intellia Therapeutics: Current Employment. Tan: Intellia Therapeutics: Current Employment. Averill: Intellia Therapeutics: Current Employment. Ranade: Intellia Therapeutics: Current Employment. Balwani: Intellia Therapeutics: Current Employment. Dutta: Intellia Therapeutics: Current Employment. Sharma: Intellia Therapeutics: Current Employment. Venkatesan: Intellia Therapeutics: Current Employment. Liu: Intellia Therapeutics: Current Employment. Roy: Intellia Therapeutics: Current Employment. O′Connell: Intellia Therapeutics: Current Employment. Arredouani: Intellia Therapeutics: Current Employment. Keenan: Intellia Therapeutics: Current Employment. Lescarbeau: Intellia Therapeutics: Current Employment. Schultes: Intellia Therapeutics: Current Employment.

Making a Killer: Selecting the Optimal Natural Killer Cells for Improved Immunotherapies.

Over the past 20 years natural killer (NK) cell-based immunotherapies have emerged as a safe and effective treatment option for patients with relapsed or refractory leukemia. Unlike T cell-based therapies, NK cells harbor an innate capacity to eliminate malignant cells without prior sensitization and can be adoptively transferred between individuals without the need for extensive HLA matching. A wide variety of therapeutic NK cell sources are currently being investigated clinically, including allogeneic donor-derived NK cells, stem cell-derived NK cells and NK cell lines. However, it is becoming increasingly clear that not all NK cells are endowed with the same antitumor potential. Despite advances in techniques to enhance NK cell cytotoxicity and persistence, the initial identification and utilization of highly functional NK cells remains essential to ensure the future success of adoptive NK cell therapies. Indeed, little consideration has been given to the identification and selection of donors who harbor NK cells with potent antitumor activity. In this regard, there is currently no standard donor selection criteria for adoptive NK cell therapy. Here, we review our current understanding of the factors which govern NK cell functional fate, and propose a paradigm shift away from traditional phenotypic characterization of NK cell subsets towards a functional profile based on molecular and metabolic characteristics. We also discuss previous selection models for NK cell-based immunotherapies and highlight important considerations for the selection of optimal NK cell donors for future adoptive cell therapies.

P34.02 The Inhibitory Effect of Cisplatin, Paclitaxel, and Pemetrexed on the Growth of PC9GR Cells During the COVID-19 Pandemic

Lung cancer patients have a significantly higher risk of contracting COVID-19, and interactions with the healthcare system during cancer therapy can put patients at risk. Preliminary studies in COVID-19 patients with severe disease found a reduction in the number and function of natural killer (NK) cells. Other studies in COVID-19 patients reported acute respiratory distress syndrome (ARDS) due to the extreme release of inflammatory cytokines. Besides, adverse effects of chemotherapy, such as chemotherapy resistance and the escalation of cellular senescence can worsen the condition of patients with COVID-19.

Functions of NK and iNKT cells in pediatric and adult CVID, ataxia telangiectasia and agammaglobulinemia patients

Primary immune deficiencies (PID) are known to be more than 400 genetic defects caused by the impairment in development and/or functions of the immune system. Common Variable Immunodeficiency (CVID), Ataxia Telangiectasia (AT) and Agammaglobulinemia (AG) are examples of the most common immunodeficiency syndrome. Natural killer (NK) cells are a component of innate immune system and play a major role in the host-rejection of both tumors and virally infected cells. iNKT cells have a role in autoimmune and infectious diseases and controlling of tumor rejection. In this study, NK and iNKT cells and their functions, and intracellular cytokine amount are aimed to determine in patients that suffer CVID, AT and AG. NKp30, NKp46, NKG2D, perforin and granzyme mRNA expression levels were analyzed using RT-PCR. Receptors, cytokine amount of NK cell subset and iNKT were analyzed by flow cytometry. Decreased CD3+ T and elevated NK cell subset in pediatric AT were found. Expression of NKp44 was decreased in adult AG, but not in pediatric patients. Low NKp44 expression in CD3−CD16+CD56dim NK cell subset was found in pediatric AT patients. High HLA-DR, perforin and granzyme expression were found in CD3−CD16+CD56dim NK cell subset of pediatric CVID and AT patients. Alteration of the number of NK subsets, NK receptor expression and cytokine production were observed in pediatric patients compared to healthy subjects.

Finding the best haematopoietic stem cell transplant regimen for GATA2 haploinsufficiency: how close are we?

Finding the best haematopoietic stem cell transplant regimen for GATA2 haploinsufficiency: how close are we?

Functional NK Cell Activation by Ovalbumin Immunization with a Monophosphoryl Lipid A and Poly I:C Combination Adjuvant Promoted Dendritic Cell Maturation.

Natural killer (NK) cells are one of the types of innate immune cells to remove pathogen-infected cells and modulate inflammatory immune responses. Recent studies have revealed that NK cells could enhance vaccine efficacy by coordinating the innate and adaptive immune responses. In this study, we have evaluated the efficacy of intranasal ovalbumin (OVA) immunization with a monophosphoryl lipid A (MPL) and polyriboinosinic polyribocytidylic acid (poly I:C) combination adjuvant in promoting NK cell recruitment, differentiation, and activation. The frequencies of NK cells were positively correlated with those of dendritic cells (DCs) at the site of immunization. Moreover, the activated NK cells and DCs by the MPL + poly I:C combination adjuvant induced activations of each other cells in vitro. Taken together, this study suggested that the MPL and poly I:C combination adjuvant in OVA vaccination mediated NK cell activation and cellular crosstalk between NK cells and DCs, suggesting a promising vaccine adjuvant candidate for promoting cellular immune responses.

Perforin, COVID-19 and a possible pathogenic auto-inflammatory feedback loop.

During COVID‐19 infection, reduced function of natural killer (NK) cells can lead to both compromised viral clearance and dysregulation of the immune response. Such dysregulation leads to overproduction of cytokines, a raised neutrophil/lymphocyte ratio and monocytosis. This in turn increases IL‐6 expression, which promotes scar and thrombus formation. Excess IL‐6 also leads to a further reduction in NK function through downregulation of perforin expression, therefore forming a pathogenic auto‐inflammatory feedback loop. The perforin/granzyme system of cytotoxicity is the main mechanism through which NK cells and cytotoxic T lymphocytes eliminate virally infected host cells, as well as being central to their role in regulating immune responses to microbial infection. Here, we present epidemiological evidence suggesting an association between perforin expression and resistance to COVID‐19. In addition, we outline the manner in which a pathogenic auto‐inflammatory feedback loop could operate and the relationship of this loop to genes associated with severe COVID‐19. Such an auto‐inflammatory loop may be amenable to synergistic multimodal therapy.

Promoting the Effector Function of Natural Killer (NK) Cells with a Focus on Bispecific Redirecting Antibodies

Promoting the Effector Function of Natural Killer (NK) Cells with a Focus on Bispecific Redirecting Antibodies

NK Cells in a Tug-of-War With Cancer: The Roles of Transcription Factors and Cytoskeleton.

Natural killer (NK) cells are innate immune cells which play a key role in shaping the immune response against cancer. Initially hailed for their potential to recognise and eliminate tumour cells, their application has been greatly hindered by the immunosuppressive tumour microenvironment (TME) which suppresses NK functions (e.g., cytotoxicity). This dysfunctional state that is accompanied by phenotypic changes such as upregulation of inhibitory receptors and downregulation of activating receptors, forms the basis of what many researchers have referred to as ‘exhausted’ NK cells. However, there is no consensus on whether these phenotypes are sufficient to define an exhausted state of the NK cell. While recent advances in checkpoint inhibition appear to show promise in early-stage pre-clinical studies, much remains to be fully explored and understood in the context of the TME. The TME is where the NK cells are subjected to interaction with various cell types and soluble factors, which could exert an inhibitory effect on NK cytotoxicity. In this review, we provide an overview of the general markers of NK cell exhaustion viz, the surface activating and inhibitory receptors. We also highlight the potential role of T-box transcription factors in characterising such a dysfunctional state and discuss the often-overlooked mechanism of cell cytoskeletal dynamics in regulating NK cell function. These aspects may further contribute to NK exhaustion or NK revival in cancer and may open new avenues to explore cancer treatment strategies.

Can anesthetic effects and pain treatment influence the long-term prognosis of early-stage lymph node-negative breast cancer after breast-conserving surgery?

BackgroundBreast cancer is currently the leading cause of women’s death. It is crucial to further improve the approach to treatment and the long-term survival rate of breast cancer patients, and to reduce the rates of recurrence and metastasis. It has been reported that the possibility of tumor metastasis depends on the metastatic potential of the tumor and the host defense against tumor metastasis, in which cellular immunity and the function of natural killer (NK) cells are critical to maintaining this balance. Surgical stress response and postoperative pain inhibit perioperative immune function in patients and increase the likelihood of dissemination and metastasis of cancer cells after cancer surgery. The study aims to investigate the effect of anesthetic factors and pain treatment on the long-term prognosis of patients with early stage lymph node negative breast preservation surgery.MethodsA total of 337 patients with early-stage lymph node negative breast cancer (ASA I-II) who had undergone successful breast-conserving surgery in our hospital were included in this retrospective analysis. Cases were divided into general anesthesia with postoperative analgesia group (GA + PCA), general anesthesia without postoperative analgesia group (GA), epidural anesthesia with postoperative analgesia group (EA + PCA), and epidural anesthesia without postoperative analgesia group (EA). The 5-year survival rate and 5-year disease-free survival were recorded in the 4 groups.ResultsThe general condition and length of hospital stay of the patients were not statistically different between the 4 groups. However, the 5-year survival rate and 5-year disease-free survival rate of the 4 groups were statistically different. The 5-year survival rate and 5-year disease-free survival rate were the lowest in the GA group, while the EA + PCA group had the highest 5-year disease-free survival rate. The 5-year survival rate and 5-year disease-free survival rate in the GA + PCA group were significantly higher than those in the GA group. The 5-year disease-free survival rate in EA group was significantly higher than GA group.ConclusionsEpidural anesthesia and postoperative pain treatment maybe beneficial to the long-term prognosis of patients with early-stage lymph node-negative breast cancer.

Macrophages and fibroblasts underpin skin immune responses

There are various types of skin immune responses including inflammatory skin diseases and skin malignancy. Macrophages and fibroblasts are skin resident cells that had been overlooked in terms of immunological research targets. In this review, cross talk among macrophages, fibroblasts, and migratory immune cells in skin diseases such as atopic dermatitis (AD), contact hypersensitivity, psoriasis, systemic sclerosis, melanoma, and cutaneous T-cell lymphoma is described. Macrophages are important in AD by antigen-presenting phagocytosis, production of inflammatory cytokines, removal of apoptotic cells, and mediating clusters between dendritic cells (DCs) and T cells. They are also increased in lesional skin of psoriasis, especially in stable plaques, and an increased ratio of M1/M2 macrophages and tumor necrosis factor-α production by macrophages are essential for development of psoriasis. The progression of skin malignancy is mediated by macrophages through promotion of tumor survival pathways via expression of cytokines and growth factors, interaction with regulatory T cells (Tregs) and myeloid-derived suppressor cells, and suppression of function of tumor-infiltrating T cells by immunosuppressive cytokines and programmed death-ligand (PD-L)1. Fibroblasts play important roles in development and maintenance of AD lesions through expression of CC chemokine ligand (CCL)17, CCL11, CCL26, C-X-C motif chemokine ligand (CXCL)12, CCL19, and periostin, interacting with T helper (Th)2 cells, natural killer T (NKT) cells, DCs, and keratinocytes. They also play important roles in psoriasis, expressing interleukin (IL)-8 and vascular endothelial growth factor, production of fibronectin, and changes in the proteomic profiles. Fibroblasts have a critical role in the progression skin malignancy via expression of cytokines, suppression natural killer (NK) functions, and establishment of Th2-dominant microenvironment. Thus, cross talk among macrophages, fibroblasts, and migratory immune cells including T cells, DCs, and NK cells in skin diseases is important and those skin-resident cells are attracting therapeutic targets in the near future.

Role of Toll‑like receptors in natural killer cell function in acute lymphoblastic leukemia (Review)

Natural killer (NK) cells are specialized lymphocytes primarily involved in the response to infection and tumors. NK cells are characterized by the presence of specific surface molecules, as well as a wide repertoire of receptors that impart microenvironment-dependent effector functions. Among these receptors, Toll-like receptors (TLRs) can be activated to condition the NK response to either a cytotoxic or immunoregulatory phenotype. However, cellular function is frequently impaired during disorders such as cancer. In the last decade, it has become increasingly evident that the stimulation of NK cells is a requirement for their increased cytotoxic activity. TLR activation has been suggested as an alternative route for reestablishing the antitumor activity of NK cells. The present review summarizes the characteristics of NK cells, their receptors, the expression and function of NK cell TLRs, and their functional status in cancer, primarily acute lymphoblastic leukemia.

Radium-223 dichloride causes transient changes in natural killer cell population and cytotoxic function

Rationale Natural killer (NK) cells play an important role in both the innate and adaptive arms of the immune system. While previous studies have demonstrated the effects of ionizing radiation on cytotoxic function of NK cells, little is known about how a chronic exposure to high LET alpha particles emitted by radionuclides will affect both NK population size and function. This study was conducted to determine the effects of 223RaCl2 on splenic NK cell population size and function in Swiss Webster mice. Methods Swiss Webster mice were administered intravenously with 0, 50, or 600 kBq/kg 223RaCl2. Spleens were harvested at 5, 12, and 19 days post-administration. The numbers of splenocytes per spleen were enumerated and flow cytometry was used to assess changes in the distribution of splenocyte subpopulations of B, CD4 and CD8 T lymphocytes, and NK cells. NK functional activity was quantified using YAC-1 target cells and the 51Cr-release assay. Results The total number of splenocytes was unaffected by 223RaCl2. However, significant changes in the distribution of splenocyte subpopulations were observed for NK cells and CD8 T lymphocytes. NK functional activity was enhanced substantially relative to controls at 12 days post-administration, but decreased markedly by day 19. Conclusion NK functional activity is both diminished and enhanced by 223RaCl2 depending on both administered activity and time post-administration. These results suggest that there may be an optimum window of time to combine the 223RaCl2-induced antitumor NK cell response with other cancer therapies that elicit immune activation.

Transcriptome and Function of Novel Immunosuppressive Autoreactive Invariant Natural Killer T Cells That Are Absent in Progressive Multiple Sclerosis.

Background and ObjectiveThe aim of this study was to determine whether natural killer T (NKT) cells, including invariant (i) NKT cells, have clinical value in preventing the progression of multiple sclerosis (MS) by examining the mechanisms by which a distinct self-peptide induces a novel, protective invariant natural killer T cell (iNKT cell) subset.MethodsWe performed a transcriptomic and functional analysis of iNKT cells that were reactive to a human collagen type II self-peptide, hCII707-721, measuring differentially induced genes, cytokines, and suppressive capacity.ResultsWe report the first transcriptomic profile of human conventional vs novel hCII707-721–reactive iNKT cells. We determined that hCII707-721 induces protective iNKT cells that are found in the blood of healthy individuals but not progressive patients with MS (PMS). By transcriptomic analysis, we observed that hCII707-721 promotes their development and proliferation, favoring the splicing of full-length AKT serine/threonine kinase 1 (AKT1) and effector function of this unique lineage by upregulating tumor necrosis factor (TNF)-related genes. Furthermore, hCII707-721–reactive iNKT cells did not upregulate interferon (IFN)-γ, interleukin (IL)-4, IL-10, IL-13, or IL-17 by RNA-seq or at the protein level, unlike the response to the glycolipid alpha-galactosylceramide. hCII707-721–reactive iNKT cells increased TNFα only at the protein level and suppressed autologous-activated T cells through FAS-FAS ligand (FAS-FASL) and TNFα-TNF receptor I signaling but not TNF receptor II.DiscussionBased on their immunomodulatory properties, NKT cells have a potential value in the treatment of autoimmune diseases, such as MS. These significant findings suggest that endogenous peptide ligands can be used to expand iNKT cells, without causing a cytokine storm, constituting a potential immunotherapy for autoimmune conditions, including PMS.

A HER2 Tri-Specific NK Cell Engager Mediates Efficient Targeting of Human Ovarian Cancer.

Simple SummaryHER2 is a marker known to be over-expressed on breast cancer, rendering it one of the most useful solid tumor targets for antibody-based therapies. Despite expression on ovarian cancer, results targeting HER2 in this setting have been disappointing, thus requiring more aggressive approaches. Natural killer (NK) cells are known as principal mediators of cancer cell killing, but cancer cells find ways to deter them. We devised a tri-specific biological drug containing antibody fragments that simultaneously binds NK cells and cancer cells and at the same time delivers a natural cytokine signal that triggers robust NK cell expansion. In vitro studies show the drug augments NK cell killing of a number of HER2-positive human cell lines, while enhancing NK cell activation and proliferation. Studies in mice engrafted with human ovarian cancer showed the drug has anti-tumor efficacy, clearly demonstrating its ability to bolster NK cells in their ability to contain tumor cell growth. Clinical studies validated antibodies directed against HER2, trastuzumab, and pertuzumab, as useful methodology to target breast cancer cases where HER2 is expressed. The hope was that HER2 targeting using these antibodies in ovarian cancer patients would prove useful as well, but clinical studies have shown lackluster results in this setting, indicating a need for a more comprehensive approach. Immunotherapy approaches stimulating the innate immune system show great promise, although enhancing natural killer (NK) function is not an established mainstream immunotherapy. This study focused on a new nanobody platform technology in which the bispecific antibody was altered to incorporate a cytokine. Herein we describe bioengineered CAM1615HER2 consisting of a camelid VHH antibody fragment recognizing CD16 and a single chain variable fragment (scFv) recognizing HER2 cross-linked by the human interleukin-15 (IL-15) cytokine. This tri-specific killer engager (TriKETM) showed in vitro prowess in its ability to kill ovarian cancer human cell lines. In addition, we demonstrated its efficacy in inducing potent anti-cancer effects in an in vivo xenograft model of human ovarian cancer engrafting both cancer cells and human NK cells. While previous approaches with trastuzumab and pertuzumab faltered in ovarian cancer, the hope is incorporating targeting and cytokine priming within the same molecule will enhance efficacy in this setting.