NKT Cells Research Articles

Abstract 6659: Oncolytic herpes simplex virus expressing XCL1 and FLT3L modulate the intratumoral immune response and improve the anti-tumor efficacy in a metastatic breast tumor model

Abstract Patients with metastatic breast cancer (MBC) have a dismal prognosis, with a 5-year survival rate of only 26%. The inadequate infiltration of immune cells targeting the tumor microenvironment (TME) is a key factor contributing to this low survival rate. Immune effector cells, including CD8+ cytotoxic T cells, NKT cells, and NK cells, play a crucial role in targeting tumor cells. The activation of immune effector cells relies on the presence of conventional type I dendritic cells (cDC1), which present tumor-specific antigenic peptides on their surface. Recent studies have identified the chemokine XCL1 and growth factor FLT3L as critical factors involved in the intratumoral recruitment and expansion of dendritic cells. To enhance the activity of cDC1 in the TME we designed an oncolytic herpes simplex virus (oHSV) expressing XCL1 and FLT3L. The recombinant oHSV, rQ1-XF, was generated by incorporating LoxP sites into the viral genome through recombination with a carrier plasmid carrying the polycistronic cassette. To enhance the intratumoral penetration of oHSV injected intravenously in primary tumors and MBC lesions in the lung, we employed the cancer drug ganetespib, which can increase the permeability of tumor blood vessels. In comparison to untreated mice, ganetespib combined with rQ1-XF reduced the size of primary tumors and induced a short but significant increase in the survival of mice. Additionally, compared to the ganetespib alone treatment, ganetespib combined with rQ1-XF reduced MBC burden in the lung. The flow cytometry analysis of immune cells revealed an increased infiltration of CD11c+CD11b- dendritic cells in primary tumors treated with oHSV combination therapy compared to the ganetespib only control. A similar trend was also observed in CD4 T cells and CD8 T cells in primary tumors. As expected, there was a negative correlation between tumor burden and the infiltration of CD4+ T cells and CD8+ T cells in primary tumors. Ganetespib combined with oHSV also reduced the infiltration of CD4+ regulatory T cells (Tregs) in primary tumors, however the number of Tregs increased with primary tumor size as well as tumor burden in the lung. This could potentially lead to reduced efficacy of tumor-infiltrating dendritic cells in activating effector T cells in tumors treated with ganetespib and rQ1-XF. Moreover, the combination therapy did not yield significant alterations in the populations of DCs, CD4+ T cells, and CD8+ T cells in lungs with metastatic lesions. Further studies are underway to investigate whether the depletion of Treg cells in combination with rQ1-XF enhances effector T cell activation against metastatic breast tumor cells. The findings of this study will provide valuable insights into the effectiveness of using XCL1 and FLT3L-armed oncolytic viruses in patients with MBC. Citation Format: Himanshu Soni, Liqun Gu, Sylvie Roberge, Heena Kumra, Hiroshi Nakashima, E. Antonio Chiocca, Yves Boucher. Oncolytic herpes simplex virus expressing XCL1 and FLT3L modulate the intratumoral immune response and improve the anti-tumor efficacy in a metastatic breast tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6659.

Abstract 4110: Identification of tumor peptides for therapeutic mRNA vaccination in a mouse multiple myeloma model

Abstract Background: Multiple myeloma (MM) is a plasma cell cancer for which immunotherapy holds the promise of durable control. To date, cancer vaccines mainly focused on tumor-associated antigens with survivin eliciting protective T-cell responses in both preclinical and clinical studies. Given the success of mRNA vaccines in medicine, we developed Galsomes, lipid nanoparticles containing mRNA and α-galactosyl ceramide to activate both CD8+ T cells and invariant natural killer (iNK) T cells, both potential anti-MM effectors. Materials and Methods: Mouse 5T33MM cells were studied by PCR and flow cytometry (FCM) for expression of survivin and CD1d, respectively. Intravenous (IV) prime-boost Galsome vaccination was performed with a 7-day interval in C57BL6/KalwRij mice that received an IV injection of 5x106 5T33MM cells 3 days earlier. As a control, mice were injected with saline. After 2 weeks, MM burden was studied by serum electrophoresis and FCM, incl. expression of CD1d and PD-L1 on MM cells. Activation of iNKT cells and survivin-specific T cells was studied by measuring IFN-γ secretion in ELISA and dextramer staining. Immunopeptidomics was used to identify new vaccine candidates for which Galsome vaccination is ongoing. Result: The 5T33MM cells showed expression of survivin and CD1d, making it a suitable model for Galsome vaccination. Two weeks following prime-boost vaccination, the serum M-protein was reduced, though not significantly. In contrast, MM cells were significantly reduced in bone marrow and spleen. Expression of CD1d and PD-L1 on MM cells was high but unchanged by Galsome vaccination. Activation of iNKT cells and survivin-specific T cells following prime vaccination was shown. However, following boost vaccination these cell populations reduced significantly compared to control. We repeated prime-boost vaccination in healthy mice, observing a similar outcome. This suggests that the negative effect of the boost Galsome vaccination was not related to immune dysfunctionality due to MM progression. So, we studied the impact of survivin mRNA in the vaccine, as survivin is also expressed in activated T cells, making them a potential target. We observed that iNKT cells and ovalbumin-specific T cells were more reduced when ovalbumin mRNA was paired with survivin mRNA in the Galsomes. To identify other vaccine candidates, we studied peptides eluted from MHC-I/peptide complexes on 5T33MM cells. We selected 4 vaccine candidates including the MM idiotype based on immunogenicity, pathway classification and abundance. mRNA and Galsomes were prepared, and the efficacy of these Galsomes in 5T33MM mice is currently under evaluation. Conclusion: These data show that Galsome vaccination has the potential to reduce MM cell levels. To reach higher efficacy, careful selection of the vaccine antigen is required. Moreover, combination with other immunotherapies might be needed to reach durable disease control. Citation Format: Arne Van der Vreken, Fabien Thery, Sofie Meulewaeter, Karin Vanderkerken, Elke De Bruyne, Kim De Veirman, Lorenzo Franceschini, Rein Verbeke, Francis Impens, Ine Lentacker, Karine Breckpot, Eline Menu. Identification of tumor peptides for therapeutic mRNA vaccination in a mouse multiple myeloma model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4110.

The central role of natural killer cells in mediating acute myocarditis after mRNA COVID-19 vaccination

Vaccine-related acute myocarditis is recognized as a rare and specific vaccine complication following mRNA-based COVID-19 vaccinations. The precise mechanisms remain unclear. We hypothesized that natural killer (NK) cells play a central role in its pathogenesis. Samples from 60 adolescents with vaccine-related myocarditis were analyzed, including pro-inflammatory cytokines, cardiac troponin T, genotyping, and immunophenotyping of the corresponding activation subsets of NK cells, monocytes, and Tcells. Results were compared with samples from 10 vaccinated individuals without myocarditis and 10 healthy controls. Phenotypically, high levels of serum cytokines pivotal for NK cells, including interleukin-1β (IL-1β), interferon α2 (IFN-α2), IL-12, and IFN-γ, were observed in post-vaccination patients with myocarditis, who also had high percentage of CD57+ NK cells in blood, which in turn correlated positively with elevated levels of cardiac troponin T. Abundance of the CD57+ NK subset was particularly prominent in malesand in those after the second dose of vaccination. Genotypically, killer cell immunoglobulin-like receptor (KIR) KIR2DL5B(-)/KIR2DS3(+)/KIR2DS5(-)/KIR2DS4del(+) was a risk haplotype, in addition to single-nucleotide polymorphisms related to the NK cell-specific expression quantitative trait loci DNAM-1 and FuT11, which also correlated with cardiac troponin T levels in post-vaccination patients with myocarditis. Collectively, these data suggest that NK cell activation by mRNA COVID-19 vaccine contributed to the pathogenesis of acute myocarditis in genetically and epidemiologically vulnerable subjects. This work was funded by the Hong Kong Collaborative Research Fund (CRF) 2020/21 and the CRF Coronavirus and Novel Infectious Diseases Research Exercises (reference no. C7149-20G).

Abstract 1331: MiNK-215, an IL-15 armored FAP-targeting CAR iNKT cell therapy, effectively treats human organoid models of treatment-refractory MSS colorectal cancer (CRC) liver metastases

Abstract The presence of liver metastases in patients with microsatellite-stable (MSS) or mismatch repair proficient (pMMR) colorectal cancer (CRC) is associated with poor response to current pharmacological treatments, including immune checkpoint blockade (ICB). The tumor microenvironment (TME) of CRC liver metastases is characterized by a highly immunosuppressive phenotype that includes poor immunogenicity, a paucity of dendritic cells, elimination of tumor-specific effector T cells, and an abundance of immunosuppressive intrahepatic Kupffer cells and myeloid-derived suppressor cells. This underscores the urgent need for innovative therapeutic approaches targeted specifically to patients with CRC liver metastases. Here we describe MiNK-215, an IL-15 armored FAP-targeting CAR iNKT cell therapy, derived from the AgenT-797 allogeneic iNKT platform, as a potential novel therapeutic approach for patients with CRC liver metastases. To better model ICB refractory human MSS CRC liver metastases, we developed an ex vivo human organoid model that recapitulates the histological and immunological features of human disease. Organoids were comprised of MSS CRC cells engineered to express nuclear GFP and HLA-A2-NY-ESO-1, hepatocytes, Kupffer cell-enriched non-parenchymal cells, and HLA-matched peripheral blood mononuclear cells (PBMCs) supplemented with NY-ESO-1-reactive T cells. Organoid models of CRC lung metastases, which are traditionally more responsive to ICB therapy were also developed to compare the models to clinical experience and further validate their usefulness. Models were treated with Fc-enhanced anti-CTLA-4 (botensilimab) and anti-PD-1 (balstilimab) antibodies, or MiNK-215 to assess tumor killing and immune activation. Botensilimab and balstilimab enhanced T cell activation and cytotoxicity of CRC tumor cells in the absence of “normal” liver cells and in lung organoids. However, they were less effective in organoid models of CRC with liver metastases consistent with clinical observations. In contrast, MiNK-215 potently enhanced tumor killing by T cells in models of CRC with liver metastases. Tumor killing in CRC liver organoid models by MiNK-215 was associated with depletion of immune suppressive FAP-expressing stellate cells and increased CD8+ T cell infiltration. Our findings demonstrate that in treatment-refractory CRC-liver metastatic organoid models, MiNK-215 overcomes the limitations of ICB therapy to home to sites of disease, reprogram the TME, recruit tumor-reactive T cells and enhance tumor killing. Ex-vivo human CRC liver and lung metastatic organoid models are a novel platform that can be leveraged to rapidly identify new therapeutic approaches for potential clinical evaluation. Citation Format: Shanmugarajan Krishnan, Bishnu Joshi, Justin Keith, Ryan Frazier, Barbara Kalinowska, Jin San Choi, Stephanie Sanders, Shannon Boi, Olivier Le Tonqueze, Nick Kushner, Kah Teong Soh, Robert Stein, Tyler J. Curiel, Marc A. van Dijk, Enoch Kim, Eleni Chantzoura, Nils-Petter Rudqvist, Dhan Chand. MiNK-215, an IL-15 armored FAP-targeting CAR iNKT cell therapy, effectively treats human organoid models of treatment-refractory MSS colorectal cancer (CRC) liver metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1331.

Abstract P297: Associations Between Short-Term Outdoor Heat Measures and Markers of Immune Response and Inflammation

Introduction: Extreme-heat events increase mortality, and excessive deaths due to heat waves are overwhelmingly cardiovascular in origin. However, many previous studies only consider ambient temperature, which fails to capture the actual heat stress experienced by populations. Hot weather can interfere with a variety of biological processes including the promotion of systemic inflammatory responses, which play a critical role in the progression of cardiovascular disease (e.g., atherosclerosis). Our objective was to assess how short-term heat exposures are related to markers of inflammation and the immune response using physiologically-relevant heat metrics that capture additional meteorological conditions. Methods: Adult participants, aged 20-70 years, were recruited from a neighborhood in Louisville, KY during the summer months of 2018 and 2019. Circulating cytokines and immune cells were measured in 624 participants at baseline. Heat metrics, including temperature, net effective temperature, and Universal Thermal Climate Index (UTCI) were calculated as the 24hr mean on the day of participants’ clinical visit. Linear regression models were used to estimate associations between heat metrics and each biomarker, adjusting for socio-demographic and behavioral factors. Results: Participants were predominantly female (59%) and White (77%), with an average age of 49.5 years. The median daily temperature during study visits was 24.5 degrees C (IQR=3.8 degrees). The mean daily UTCI was positively associated with total circulating monocytes (4.2% per IQR; 95% CI: 0.3, 8.3), and classical monocytes (CD14 hi CD16 lo ), while nonclassical monocytes (CD14 lo CD16 hi ) displayed a negative association. We also observed positive associations with eosinophils 9.5% per IQR (95% CI: 0.6, 19.1) and Natural Killer T-Cells 9.9% per IQR (95% CI:2.8, 17.5), and a negative association with B-cells -6.8% per IQR (95% CI: -12.1, -1.1). In our cytokine analysis, UTCI was positively associated with TNF-alpha 7.0% per IQR (95% CI:2.8, 11.4) as well as IL-5 and MIP-1α. Similar, but attenuated associations were observed using daily temperature and other heat metrics. Conclusion: Short-term heat exposure may trigger an inflammatory response characterized by innate immune activation as evidenced by our results of higher total monocytes, classical monocytes, and TNF-alpha. Moreover, short-term heat exposure may impair adaptive immune response. These results suggest that exposure to high temperatures may increase susceptibility to infectious agents, environmental exposures, and accelerate the progression of cardiovascular disease.

Kidins220 and Aiolos promote thymic iNKT cell development by reducing TCR signals.

Development of T cells is controlled by the signal strength of the TCR. The scaffold protein kinase D-interacting substrate of 220 kilodalton (Kidins220) binds to the TCR; however, its role in T cell development was unknown. Here, we show that T cell-specific Kidins220 knockout (T-KO) mice have strongly reduced invariant natural killer T (iNKT) cell numbers and modest decreases in conventional T cells. Enhanced apoptosis due to increased TCR signaling in T-KO iNKT thymocytes of developmental stages 2 and 3 shows that Kidins220 down-regulates TCR signaling at these stages. scRNA-seq indicated that the transcription factor Aiolos is down-regulated in Kidins220-deficient iNKT cells. Analysis of an Aiolos KO demonstrated that Aiolos is a downstream effector of Kidins220 during iNKT cell development. In the periphery, T-KO iNKT cells show reduced TCR signaling upon stimulation with α-galactosylceramide, suggesting that Kidins220 promotes TCR signaling in peripheral iNKT cells. Thus, Kidins220 reduces or promotes signaling dependent on the iNKT cell developmental stage.

GD2-targeting therapy: a comparative analysis of approaches and promising directions.

Disialoganglioside GD2 is a promising target for immunotherapy with expression primarily restricted to neuroectodermal and epithelial tumor cells. Although its role in the maintenance and repair of neural tissue is well-established, its functions during normal organism development remain understudied. Meanwhile, studies have shown that GD2 plays an important role in tumorigenesis. Its functions include proliferation, invasion, motility, and metastasis, and its high expression and ability to transform the tumor microenvironment may be associated with a malignant phenotype. Structurally, GD2 is a glycosphingolipid that is stably expressed on the surface of tumor cells, making it a suitable candidate for targeting by antibodies or chimeric antigen receptors. Based on mouse monoclonal antibodies, chimeric and humanized antibodies and their combinations with cytokines, toxins, drugs, radionuclides, nanoparticles as well as chimeric antigen receptor have been developed. Furthermore, vaccines and photoimmunotherapy are being used to treat GD2-positive tumors, and GD2 aptamers can be used for targeting. In the field of cell therapy, allogeneic immunocompetent cells are also being utilized to enhance GD2 therapy. Efforts are currently being made to optimize the chimeric antigen receptor by modifying its design or by transducing not only αβ T cells, but also γδ T cells, NK cells, NKT cells, and macrophages. In addition, immunotherapy can combine both diagnostic and therapeutic methods, allowing for early detection of disease and minimal residual disease. This review discusses each immunotherapy method and strategy, its advantages and disadvantages, and highlights future directions for GD2 therapy.

A Humanized Mouse Model Coupled with Computational Analysis Identifies Potent Glycolipid Agonist of Invariant NKT Cells.

Invariant natural killer T (iNKT) cells play an important role in many innate and adaptive immune responses, with potential applications in cancer immunotherapy. The glycolipid KRN7000, an α-galactosylceramide, potently activates iNKT cells but has shown limited anticancer effects in human clinical trials conducted so far. In spite of almost three decades of structure-activity relationship studies, no alternative glycolipid has yet emerged as a superior clinical candidate. One reason for the slow progress in this area is that standard mouse models do not accurately reflect the specific ligand recognition by human iNKT cells and their requirements for activation. Here we evaluated a series of KRN7000 analogues using a recently developed humanized mouse model that expresses a human αTCR chain sequence and human CD1d. In this process, a more stimulatory, previously reported but largely overlooked glycolipid was identified, and its activity was probed and rationalized via molecular simulations.

Granulysin-mediated reduction of PDZRN3 induces Cx43 gap junctions activity exacerbating skin damage in trichloroethylene hypersensitivity syndrome

Trichloroethylene (TCE)-induced hypersensitivity syndrome (THS) has been a concern for many researchers in the field of environmental and occupational health. Currently, there is no specific treatment for THS, leaving patients to contend with severe infections arising from extensive skin lesions, consequently leading to serious adverse effects. However, the pathogenesis of severe skin damage in THS remains unclear. This study aims to investigate the specific danger signals and mechanisms underlying skin damage in THS through in vivo and in vitro experiments. We identified that cell supernatant containing 15 kDa granulysin (GNLY), released from activated CD3-CD56+NK cells or CD3+CD56+NKT cells in PBMC induced by TCE or its metabolite, promoted apoptosis in HaCaT cells. The apoptosis level decreased upon neutralization of GNLY in the supernatant by a GNLY-neutralizing antibody in HaCaT cells. Subcutaneous injection of recombinant 15 kDa GNLY exacerbated skin damage in the THS mouse model and better mimicked patients’ disease states. Recombinant 15 kDa GNLY could directly induce cellular communication disorders, inflammation, and apoptosis in HaCaT cells. In addition to its cytotoxic effects, GNLY released from TCE-activated NK cells and NKT cells or synthesized GNLY alone could induce aberrant expression of the E3 ubiquitin ligase PDZRN3, causing dysregulation of the ubiquitination of the cell itself. Consequently, this resulted in the persistent opening of gap junctions composed of connexin43, thereby intensifying cellular inflammation and apoptosis through the “bystander effect”. This study provides experimental evidence elucidating the mechanisms of THS skin damage and offers a novel theoretical foundation for the development of effective therapies targeting severe dermatitis induced by chemicals or drugs.

Distinct disease-modifying therapies are associated with different blood immune cell profiles in people with relapsing-remitting multiple sclerosis

Disease modifying therapies (DMTs) used for treating people with relapsing-remitting multiple sclerosis (pwRRMS) target the immune system by different mechanisms of action. However, there is a lack of a comprehensive assessment of their effects on the immune system in comparison to treatment-naïve pwRRMS. Herein, we evaluated the numbers of circulating B cells, CD4+ and CD8+ T cells, regulatory T cells (Tregs), natural killer (NK) cells and NKT cells, and their subsets, in pwRRMS who were treatment-naïve or treated with different DMTs. Compared to treatment-naïve pwRRMS, common and divergent effects on immune system cells were observed on pwRRMS treated with different DMTs, with no consistent pattern across all therapies in any of the cell populations analysed. PwRRMS treated with fingolimod, dimethyl fumarate (DMF), or alemtuzumab have reduced numbers of CD4+ and CD8+ T cells, as well as Treg subsets, with fingolimod causing the most pronounced decrease in T cell subsets. In contrast, teriflunomide and interferon (IFN) β have minimal impact on T cells, and natalizumab marginally increases the number of memory T cells in the blood. The effect of DMTs on the B cell, NKT and NK cell subsets is highly variable with alemtuzumab inducing a strong increase in the number of the most immature NK cells and its subsets.This study comprehensively evaluates the magnitude of the effect of different DMTs on blood immune cells providing a better understanding of therapy outcome. Furthermore, the lack of a discernible pattern in the effects of DMTs on blood immune cells suggests that multiple immune cells can independently modulate the disease.

Role of sulfatide-reactive vNKT cells in promoting lung Treg cells via dendritic cell modulation in asthma models

Our previous studies have showed that sulfatide-reactive type II NKT (i.e. variant NKT, vNKT) cells inhibit the immunogenic maturation during the development of mature lung dendritic cells (LDCs), leading todeclined allergic airway inflammation in asthma. Nonetheless, the specific immunoregulatory roles of vNKT cells in LDC-mediated Th2 cell responses remain incompletely understood. Herein, we found that administration of sulfatide facilitated the generation of CD4+FoxP3+ regulatory T (Treg) cells in the lungs of wild-type mice, but not in CD1d−/− and Jα18−/− mice, after ovalbumin or house dust mite exposure. This finding implies that the enhancement of lung Treg cells by sulfatide requires vNKT cells, which dependent on invariant NKT (iNKT) cells. Furthermore, the CD4+FoxP3+ Treg cells induced by sulfatide-reactive vNKT cells were found to be associated with PD-L1 molecules expressed on LDCs, and this association was dependent on iNKT cells. Collectively, our findings suggest that in asthma-mimicking murine models, sulfatide-reactive vNKT cells facilitate the generation of lung Treg cells through inducing tolerogenic properties in LDCs, and this process is dependent on the presence of lung iNKT cells. These results may provide a potential therapeutic approach to treat allergic asthma.

Update on T-Cell Lymphoma Epidemiology.

T-cell lymphomas (TCLs) are a group of rare subtypes of non-Hodgkin lymphoma derived from mature T-lymphocytes. Recent updates in lymphoma classification based on the cell-of-origin pathogenesis have shed new light on TCL epidemiology and outcomes. Contemporary regional consortia and international studies, including those conducted recently in Asia and South America, have provided an updated delineation of the major subtypes across various global regions. Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), remains the most common subtype globally except in Asia, where extra-nodal NK-T cell lymphoma (ENKTL) has emerged as the most prevalent. Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype globally except in South America where its incidence falls behind adult T-cell leukemia/lymphoma (ATLL) and ENKTL. ALK-negative anaplastic large cell lymphoma (ALCL) has been recognized as the second most common subtype in some parts of South America. Studies on the newly classified breast implant-associated ALCL (BIA-ALCL) are beginning to reveal its distribution and risk factors. Deciphering the epidemiology of TCLs is a challenging endeavor due to the rarity of these entities and ongoing refinement in classification. Collaborative efforts on prospective registries based on the most current WHO classifications will help capture the true epidemiology of TCL subtypes to better focus resources for diagnostic, prognostic, and therapeutic efforts.

Comprehensive Insight into the Functional Roles of NK and NKT Cells in HTLV-1-Associated Diseases and Asymptomatic Carriers.

Human T cell leukemia virus type 1 (HTLV-1) is the first human oncogenic retrovirus to be discovered and causes two major diseases: a progressive neuro-inflammatory disease, termed HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and an aggressive malignancy of T lymphocytes known as adult T cell leukemia (ATL). Innate and acquired immune responses play pivotal roles in controlling the status of HTLV-1-infected cells and such, the outcome of HTLV-1 infection. Natural killer cells (NKCs) are the effector cells of the innate immune system and are involved in controlling viral infections and several types of cancers. The ability of NKCs to trigger cytotoxicity to provide surveillance against viruses and cancer depends on the balance between the inhibitory and activating signals. In this review, we will discuss NKC function and the alterations in the frequency of these cells in HTLV-1 infection.

Pooled analysis of pralatrexate single-agent studies in patients with relapsed/refractory peripheral T-cell lymphoma

AbstractPatients with relapsed or refractory (R/R) mature natural killer cell and T-cell lymphoma have limited treatment options. To evaluate pralatrexate’s performance and factors influencing its safety and efficacy in R/R peripheral T-cell lymphoma (PTCL), we performed a pooled analysis of data from 4 similarly designed, regulatory-mandated prospective clinical trials. Of 221 patients (median age, 59 years; 67.0% male) in the study population, 48.9% had PTCL not otherwise specified (PTCL-NOS), 21.3% angioimmunoblastic T-cell lymphoma, and 11.8% ALK-negative anaplastic large cell lymphoma (ALCL). Patients received pralatrexate for a median of 2.56 months (range, 0.03-24.18) and had a 40.7% objective response rate with a median duration of response of 9.1 months, progression-free survival 4.6 months, and overall survival 16.3 months. The most common treatment-related all-grade adverse events were stomatitis, thrombocytopenia, white blood cell count decrease, pyrexia, and vomiting. Subgroup exploratory analyses suggest improved efficacy with 1 prior line of chemotherapy vs 2 or ≥4 prior lines; PTCL-NOS or ALCL vs transformed mycosis fungoides; chemotherapy and transplant before pralatrexate vs chemotherapy alone or chemotherapy with other nontransplant treatments. In conclusion, these pooled analysis results further support using pralatrexate in patients with R/R PTCL. Prospective studies are needed to confirm the findings of subgroups analyses.

Mechanism and endoscopic-treatment-induced evolution of biliary non-anastomotic stricture after liver transplantation revealed by single-cell RNA sequencing.

Biliary complications, especially non-anastomotic stricture (NAS), are the main complications after liver transplantation. Insufficient sampling and no recognized animal models obstruct the investigation. Thus, the mechanisms and alterations that occur during endoscopic treatment (ET) of NAS remain unclear. Samples were obtained with endoscopic forceps from the hilar bile ducts of NAS patients receiving continuous biliary stent implantation after diagnosis. Retrospective analysis of multiple studies indicated that the duration of ET for NAS was approximately 1-2 years. Thus, we divided the patients into short-term treatment (STT) and long-term treatment (LTT) groups based on durations of less or more than 1 year. Samples were subjected to single-cell RNA sequencing. Transcriptomic differences between STT and normal groups were defined as the NAS mechanism. Similarly, alterations from STT to LTT groups were regarded as endoscopic-treatment-induced evolution. In NAS, inflammation and immune-related pathways were upregulated in different cell types, with nonimmune cells showing hypoxia pathway upregulation and immune cells showing ATP metabolism pathway upregulation, indicating heterogeneity. We confirmed a reduction in bile acid metabolism-related SPP1+ epithelial cells in NAS. Increases in proinflammatory and profibrotic fibroblast subclusters indicated fibrotic progression in NAS. Furthermore, immune disorders in NAS were exacerbated by an increase in plasma cells and dysfunction of NK and NKT cells. ET downregulated multicellular immune and inflammatory responses and restored epithelial and endothelial cell proportions. This study reveals the pathophysiological and genetic mechanisms and evolution of NAS induced by ET, thereby providing preventive and therapeutic insights into NAS. For the first time, single-cell transcriptome sequencing was performed on the bile ducts of patients with biliary complications. scRNA-seq analysis revealed distinct changes in the proportion and phenotype of multiple cell types during Nonanastomotic stricture (NAS) and endoscopic treatment. A reduction in bile acid metabolism-related SPP1+ epithelial cells and VEGFA+ endothelial cells, along with explosive infiltration of plasma cells and dysfunction of T and NK cells in NAS patients. SPP1+ macrophages and BST2+ T cells might serve as a surrogate marker for predicting endoscopic treatment.

High-Dimensional Analyses Reveal IL15 Enhances Activation of Sipuleucel-T Lymphocyte Subsets and Reverses Immunoresistance.

Sipuleucel-T (sip-T) is the only FDA-approved autologous cellular immunotherapy for metastatic castration-resistant prostate cancer (mCRPC). To elucidate parameters of the response profile to this therapy, we report high-dimensional analyses of sip-T using cytometry by time of flight (CyTOF) and show a lymphoid predominance, with CD3+ T cells constituting the highest proportion (median ∼60%) of sip-T, followed by B cells, and natural killer (NK) and NKT cells. We hypothesized that treatment of sip-T with homeostatic cytokines known to activate/expand effector lymphocytes could augment efficacy against prostate tumors. Of the cytokines tested, IL15 was the most effective at enhancing activation and proliferation of effector lymphocytes, as well as augmenting tumor cytotoxicity in vitro. Co-culture of sip-T with IL15 and control or prostate-relevant antigens showed substantial activation and expansion of CD8+ T cells and NKT cells in an antigen-specific manner. Adoptive transfer of IL15-treated sip-T into NSG mice resulted in more potent prostate tumor growth inhibition compared with control sip-T. Evaluation of tumor-infiltrating lymphocytes revealed a 2- to 14-fold higher influx of sip-T and a significant increase in IFNγ producing CD8+ T cells and NKT cells within the tumor microenvironment in the IL15 group. In conclusion, we put forward evidence that IL15 treatment can enhance the functional antitumor immunity of sip-T, providing rationale for combining IL15 or IL15 agonists with sip-T to treat patients with mCRPC.

Benidipine impairs innate immunity converting sublethal to lethal infections in a murine model of spotted fever rickettsiosis.

Spotted fever group rickettsiae are tick-borne obligate intracellular bacteria that infect microvascular endothelial cells. Humans and mammalian infection results in endothelial cell barrier dysfunction and increased vascular permeability. We previously demonstrated that treatment of Rickettsia parkeri-infected cells with the calcium channel blocker benidipine significantly delayed vascular barrier permeability. Thus, we hypothesized that benidipine, known to be safe and effective for other clinical processes, could reduce rickettsia-induced vascular permeability in vivo in an animal model of spotted fever rickettsiosis. Based on liver, lung and brain vascular FITC-dextran extravasation studies, benidipine did not reliably impact vascular permeability. However, it precipitated a deleterious effect on responses to control sublethal R. parkeri infection. Animals treated with benidipine alone had no clinical signs or changes in histopathology and splenic immune cell distributions. Benidipine-treated infected animals had marked increases in tissue and blood bacterial loads, more extensive inflammatory histopathologic injury, and changes in splenic architecture and immune cell distributions potentially reflecting diminished Ca2+ signaling, reduced innate immune cell activation, and loss of rickettsial propagation control. Impaired T cell activation by R. parkeri antigen in the presence of benidipine was confirmed in vitro with the use of NKT cell hybridomas. The unexpected findings stand in stark contrast to recent discussions of the benefits of calcium channel blockers for viral infections and chronic infectious or inflammatory diseases. A role for calcium channel blockers in exacerbation of human rickettsiosis and acute inflammatory infections should be evaluated by a retrospective review of patient's outcomes and medications.

IL-27 regulates the differentiation of follicular helper NKT cells via metabolic adaptation of mitochondria

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that express an invariant T cell receptor α chain and contribute to bridging innate and acquired immunity with rapid production of large amounts of cytokines after stimulation. Among effecter subsets of iNKT cells, follicular helper NKT (NKTFH) cells are specialized to help B cells. However, the mechanisms of NKTFH cell differentiation remain to be elucidated. In this report, we studied the mechanism of NKTFH cell differentiation induced by pneumococcal surface protein A and α-galactosylceramide (P/A) vaccination. We found that Gr-1+ cells helped iNKT cell proliferation and NKTFH cell differentiation in the spleen by producing interleukin-27 (IL-27) in the early phase after vaccination. The neutralization of IL-27 impaired NKTFH cell differentiation, which resulted in compromised antibody production and diminished protection against Streptococcus pneumoniae infection by the P/A vaccine. Our data indicated that Gr-1+ cell-derived IL-27 stimulated mitochondrial metabolism, meeting the energic demand required for iNKT cells to differentiate into NKTFH cells. Interestingly, Gr-1+ cell-derived IL-27 was induced by iNKT cells via interferon-γ production. Collectively, our findings suggest that optimizing the metabolism of iNKT cells was essential for acquiring specific effector functions, and they provide beneficial knowledge on iNKT cell-mediated vaccination-mediated therapeutic strategies.

Anti-Vα24Jα18 TCR Antibody Tunes iNKT Cell Responses to Target and Kill CD1d-negative Tumors in an FcγRII (CD32)-dependent Manner.

Our findings unveiled that iNKT cells recognize and kill CD1d-negative target tumors via the anti-iNKT TCR mAb bound to CD32 at the tumor site, thereby bridging iNKT cells and CD1d-negative tumors. These findings shed light on the therapeutic potential of anti-iNKT TCR mAbs in NKT cell-based immunotherapy to treat CD1d-negative CD32+ cancers.

Insights into the heterogeneity of iNKT cells: tissue-resident and circulating subsets shaped by local microenvironmental cues.

Invariant natural killer T (iNKT) cells are a distinct subpopulation of innate-like T lymphocytes. They are characterized by semi-invariant T cell receptors (TCRs) that recognize both self and foreign lipid antigens presented by CD1d, a non-polymorphic MHC class I-like molecule. iNKT cells play a critical role in stimulating innate and adaptive immune responses, providing an effective defense against infections and cancers, while also contributing to chronic inflammation. The functions of iNKT cells are specific to their location, ranging from lymphoid to non-lymphoid tissues, such as the thymus, lung, liver, intestine, and adipose tissue. This review aims to provide insights into the heterogeneity of development and function in iNKT cells. First, we will review the expression of master transcription factors that define subsets of iNKT cells and their production of effector molecules such as cytokines and granzymes. In this article, we describe the gene expression profiles contributing to the kinetics, distribution, and cytotoxicity of iNKT cells across different tissue types. We also review the impact of cytokine production in distinct immune microenvironments on iNKT cell heterogeneity, highlighting a recently identified circulating iNKT cell subset. Additionally, we explore the potential of exploiting iNKT cell heterogeneity to create potent immunotherapies for human cancers in the future.