Lymphocyte Function Research Articles

Ganoderma lucidum dry extract supplementation modulates T lymphocyte function in older women.

Ganoderma lucidum (a mushroom used in traditional Chinese medicine) compounds may attenuate ageing-related physiological changes and restore normal immunity. However, studies on the physiological effects of Ganoderma lucidum dry extract food supplements are few. Therefore, here, we aimed to investigate the effects of Ganoderma lucidum dry extract food supplement on the lymphocyte function of older women. This was a double-blind clinical trial (n 60) with a final 39 older volunteers, divided into two groups Ganoderma lucidum (n 23) and placebo (n 16). The Ganoderma lucidum group received 2000 mg/d of Ganoderma lucidum dry extract for 8 weeks. We used flow cytometry to determine the lymphocyte profile. CD4+ lymphocyte gene expression was evaluated by real-time polymerase chain reaction. We observed that in the Ganoderma lucidum group, concanavalin A stimulation increased lymphocyte proliferation. Further, we observed an increase in expression of Forkhead box P3, transforming growth factor-beta, IL-10, IL-6, retinoic acid receptor-related orphan receptor gamma, GATA-binding protein 3 and interferon gamma genes in the Ganoderma lucidum group. Furthermore, in the Ganoderma lucidum group, ionomycin and phorbol 12-myristate 13-acetate stimulation led to decrease in Th17+ cells and increase in Th2+ cells. Thus, in older women, Ganoderma lucidum regulates T lymphocyte function leading to a predominant anti-inflammatory action but does not induce T lymphocyte proliferation through CD28 signalling pathway.

Granulocyte Colony Stimulating Factor-Mobilized Peripheral Blood Mononuclear Cells: An Alternative Cellular Source for Chimeric Antigen Receptor Therapy.

Lymphocyte collection by apheresis for CAR-T production usually does not include blood mobilized using granulocyte colony stimulating factor (G-CSF) due to the widespread knowledge that it causes a decrease in the number and functionality of lymphocytes. However, it is used for stem cell transplant, which is a common treatment for hematological malignancies. The growing demand for CAR therapies (CAR-T and NK-CAR), both in research and clinics, makes it necessary to evaluate whether mobilized PBSC products may be potential candidates for use in such therapies. This review collects recent works that experimentally verify the role and functionality of T and NK lymphocytes and the generation of CAR-T from apheresis after G-CSF mobilization. As discussed, T cells do not vary significantly in their phenotype, the ratio of CD4+ and CD8+ remains constant, and the different sub-populations remain stable. In addition, the expansion and proliferation rates are invariant regardless of mobilization with G-CSF as well as the secretion of proinflammatory cytokines and the cytotoxic ability. Therefore, cells mobilized before apheresis are postulated as a new alternative source of T cells for adoptive therapies that will serve to alleviate high demand, increase availability, and take advantage of the substantial number of existing cryopreserved products.

Identification and Functional Analysis of a de novo IKZF3 Mutation in a Pediatric Patient with Combined Immunodeficiency.

AIOLOS, a vital member of the IKAROS protein family, plays a significant role in lymphocyte development and function through DNA binding and protein-protein interactions. Mutations in the IKZF3 gene, which encodes AIOLOS, lead to a rare combined immunodeficiency often linked with infections and malignancy. In this study, we evaluated a 1-year-4-month-old female patient presenting with recurrent infections, diarrhea, and failure to thrive. Laboratory investigations revealed decreased T lymphocyte and immunoglobulin levels. Through whole-exome and Sanger sequencing, we discovered a de novo mutation in IKZF3 (NM_012481; exon 5 c.571G > C, p.Gly191Arg), corresponding to the third DNA-binding zinc finger region of the encoded protein AIOLOS. Notably, the patient with the AIOLOS G191R mutation showed reduced recent thymic emigrants in naïve CD4+T cells compared to healthy counterparts of the same age, while maintaining normal levels of Th1, Th2, Th17, Treg, and Tfh cells. This mutation also resulted in decreased switched memory B cells and lower CD23 and IgM expression. In vitro studies revealed that AIOLOS G191R does not impact the expression of AIOLOS but compromises its stability, DNA binding and pericentromeric targeting. Furthermore, AIOLOS G191R demonstrated a dominant-negative effect over the wild-type protein. This case represents the first reported instance of a mutation in the third DNA-binding zinc finger region of AIOLOS highlighting its pivotal role in immune cell functionality.

Ex vivo characterization of acute myeloid leukemia patients undergoing hypomethylating agents and venetoclax regimen reveals a venetoclax-specific effect on non-suppressive regulatory T cells and bona fide PD-1+TIM3+ exhausted CD8+ T cells.

Acute myeloid leukemia (AML) is an aggressive heterogeneous disease characterized by several alterations of the immune system prompting disease progression and treatment response. The therapies available for AML can affect lymphocyte function, limiting the efficacy of immunotherapy while hindering leukemia-specific immune reactions. Recently, the treatment based on Venetoclax (VEN), a specific B-cell lymphoma 2 (BCL-2) inhibitor, in combination with hypomethylating agents (HMAs) or low-dose cytarabine, has emerged as a promising clinical strategy in AML. To better understand the immunological effect of VEN treatment, we characterized the phenotype and immune checkpoint (IC) receptors' expression on CD4+ and CD8+ T cells from AML patients after the first and second cycle of HMA in combination with VEN. HMA and VEN treatment significantly increased the percentage of naïve CD8+ T cells and TIM-3+ CD4+ and CD8+ T cells and reduced cytokine-secreting non-suppressive T regulatory cells (Tregs). Of note, a comparison between AML patients treated with HMA only and HMA in combination with VEN revealed the specific contribution of VEN in modulating the immune cell repertoire. Indeed, the reduction of cytokine-secreting non-suppressive Tregs, the increased TIM-3 expression on CD8+ T cells, and the reduced co-expression of PD-1 and TIM-3 on both CD4+ and CD8+ T cells are all VEN-specific. Collectively, our study shed light on immune modulation induced by VEN treatment, providing the rationale for a novel therapeutic combination of VEN and IC inhibitors in AML patients.

Regulation of T Lymphocyte Functions through Calcium Signaling Modulation by Nootkatone.

Recent advancements in understanding the intricate molecular mechanisms underlying immunological responses have underscored the critical involvement of ion channels in regulating calcium influx, particularly in inflammation. Nootkatone, a natural sesquiterpenoid found in Alpinia oxyphylla and various citrus species, has gained attention for its diverse pharmacological properties, including anti-inflammatory effects. This study aimed to elucidate the potential of nootkatone in modulating ion channels associated with calcium signaling, particularly CRAC, KV1.3, and KCa3.1 channels, which play pivotal roles in immune cell activation and proliferation. Using electrophysiological techniques, we demonstrated the inhibitory effects of nootkatone on CRAC, KV1.3, and KCa3.1 channels in HEK293T cells overexpressing respective channel proteins. Nootkatone exhibited dose-dependent inhibition of channel currents, with IC50 values determined for each channel. Nootkatone treatment did not significantly affect cell viability, indicating its potential safety for therapeutic applications. Furthermore, we observed that nootkatone treatment attenuated calcium influx through activated CRAC channels and showed anti-proliferative effects, suggesting its role in regulating inflammatory T cell activation. These findings highlight the potential of nootkatone as a natural compound for modulating calcium signaling pathways by targeting related key ion channels and it holds promise as a novel therapeutic agent for inflammatory disorders.

High Glucose Alters Endoplasmic Reticulum Ca2+ Stores in T Lymphocytes Revealing Potential Novel Therapeutic Targets for Diabetic-Induced Immune Dysfunction

The objective of this study was to examine the effects of high glucose stress on endoplasmic reticulum (ER) Ca2+ stores in T lymphocytes. Our hypothesis is that T lymphocytes exposed to chronic high glucose undergo an ER “stress” response due to impairment of Sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pump-mediated Ca2+ transport and dysregulated T cell ER Ca2+ signaling. To examine ER Ca2+ signaling events we conducted both intact and permeabilized cell Ca2+ assays using Ca2+ sensitive fluorescence dyes. Western Blot and RT-qPCR experiments were performed to detect SERCA expression levels. Our study found: 1. Incubation of T cells for an “early” phase (7-10 days) in high glucose resulted in differential changes in the SERCA 2b and SERCA 3 regulated Ca2+ stores, as revealed by our specific Ca2+ release protocol using thapsigargin and 2,5-di-( tert-butyl)-1,4-hydroquinone SERCA inhibition. 2. The early phase high glucose exposure increases Ca2+ release from the SERCA 2b-regulated Ca2+ pool whereas no change is observed in the SERCA 3-regulated pool. 3. We observed an increase in SERCA 2b expression levels during the early phase high glucose exposure but no change in SERCA 3 expression. 4. Long term high glucose exposure (>11 days) resulted in the loss of the augmented Ca2+ release response from SERCA 2b sensitive Ca2+ stores. 5. Treatment of T cells with the SERCA activator CDN1163 restored the augmented Ca2+ release response from the SERCA 2b store. 6. Treatment of T cells in the ER stress phase with the chemical chaperone TUDCA protected T cells from high glucose induced loss in viability. Summary: High glucose exposure (as an in vitro mimic of a diabetic hyperglycemia state) perturbs ER Ca2+ stores in T lymphocytes resulting in increased expression of SERCA 2b and augmented Ca2+ storage whereas no apparent change is observable in the SERCA 3 Ca2+ pool. Longer-term high glucose exposure results in the loss of the augmented SERCA 2b-sensitive store response, yet pharmacological SERCA 2b activation was able to restore enhanced Ca2+ release from this pool. Conclusion: Our results are consistent with our hypothesis that high glucose exposure imposes a stress condition on T cell ER Ca2+ stores with changes in SERCA-mediated Ca2+ uptake activity. The findings in this study reveal an intriguing differential effect with the SERCA 2b pump isoform targeted for increased expression and augmented Ca2+ storage whereas the SERCA 3-regulated Ca2+ pools appear unaffected. Our experiments with the SERCA activator CDN1163 suggest a potential novel strategy to restore critical ER Ca2+ signaling and T lymphocyte function in patients suffering from diabetic hyperglycemia. This work was supported by a SEED grant from the Jie Du Center, University of the Pacific. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Distance changes of lymphocyte quantity and function in patients with COVID-19

Distance changes of lymphocyte quantity and function in patients with COVID-19

Perforin production by T cells and Natural Killer cells in CMV-reactivated allogeneic cell transplant patients is associated with early post-transplant death

Abstract Introduction: Cytomegalovirus (CMV) is a prevalent herpesvirus that poses a serious risk to immunocompromised patients, particularly hematopoietic stem cell transplant (HSCT) recipients. CMV reactivation increases the risk of mortality due to secondary infections. CMV infection has been shown to epigenetically induce immune exhaustion and decrease non-specific immunity. Methods: We reviewed flow cytometry data from CMV seropositive HSCT recipients to determine if CMV reactivation predicted mortality via modulation of lymphocyte function. Peripheral blood mononuclear cells (PBMCs) were collected from recipients 30 days following transplant and stimulated with CMV-specific peptide pools of pp65 and staphylococcal enterotoxin B (SEB) to assess CMV-specific and non-specific immune function. Results: Non-specific, SEB-induced, polyfunctionality of CD4 and CD8 T cells was diminished in deceased CMV seropositive HSCT recipients. In deceased individuals, T-bet and perforin expression were elevated, with decreased IFNγ, TNFα, or IL2 SEB-induced production. Discussion: Mortality in CMV reactivated HSCT recipients was associated with non-specific immune exhaustion phenotypes, but it remains unclear whether this was a result of a higher pathogenic burden, recurrent CMV reactivation, or chemotherapy and myeloablation.

The role of CMKLR1 in lymphocyte activation and localization within the CNS during West Nile Virus Encephalitis

Abstract Continued West Nile virus (WNV) outbreaks causing neuroinvasive disease in the US highlight the urgent need to decipher CNS viral control mechanisms. DCs are pivotal in recruiting and reactivating CNS-infiltrating lymphocytes for viral clearance. However, the molecular mechanisms that regulate DC recruitment and activation remain unknown. In CNS-related autoimmune disorders, CMKLR1, a chemokine receptor expressed by a DC subset, aids their recruitment and activation via its ligand, chemerin. To investigate the role of CMKLR1 during WNND, we infected WT and CMKLR1-/- mice with WNV. CMKLR1-/- mice exhibited a slight increase in mortality but elevated clinical scores accompanied by increased CNS viral loads compared to WT. We hypothesize that CMKLR1 restricts WNV neuropathogenesis by regulating the activation and localization of antiviral T cells within the CNS during WNV encephalitis. Determining the role of CMKLR1 in effector T cell activation and migration may provide insights into local molecular mechanisms controlling lymphocyte function and fate within the CNS during WNV.

Immunological Response against Breast Lineage Cells Transfected with Human Papillomavirus (HPV).

Breast cancer is the most common neoplasm worldwide. Viral infections are involved with carcinogenesis, especially those caused by oncogenic Human Papillomavirus (HPV) genotypes. Despite the detection of HPV in breast carcinomas, the virus's activity against this type of cancer remains controversial. HPV infection promotes remodeling of the host's immune response, resulting in an immunosuppressive profile. This study assessed the individual role of HPV oncogenes in the cell line MDA-MB-231 transfected with the E5, E6, and E7 oncogenes and co-cultured with peripheral blood mononuclear cells. Immunophenotyping was conducted to evaluate immune system modulation. There was an increase in CD4+ T cell numbers when compared with non-transfected and transfected MDA-MB-231, especially in the Treg profile. Pro-inflammatory intracellular cytokines, such as IFN-γ, TNF-α, and IL-17, were impaired by transfected cells, and a decrease in the cytolytic activity of the CD8+ and CD56+ lymphocytes was observed in the presence of HPV oncogenes, mainly with E6 and E7. The E6 and E7 oncogenes decrease monocyte expression, activating the expected M1 profile. In the monocytes found, a pro-inflammatory role was observed according to the cytokines released in the supernatant. In conclusion, the MDA-MB-231 cell lineage transfected with HPV oncogenes can downregulate the number and function of lymphocytes and monocytes.

Therapeutic Applications of Aggregatibacter actinomycetemcomitans Leukotoxin.

Aggregatibacter actinomycetemcomitans is a Gram-negative oral bacterium that has been primarily studied for its role in causing periodontal disease. The bacterium has also been implicated in several systemic diseases such as endocarditis and soft tissue abscesses. Leukotoxin (LtxA) is perhaps the best studied protein virulence factor from A. actinomycetemcomitans. The protein can rapidly destroy white blood cells (WBCs), helping the bacterium to subvert the host immune system. The functional receptor for LtxA is lymphocyte function associated antigen-1 (LFA-1), which is expressed exclusively on the surfaces of WBCs. Bacterial expression and secretion of the protein are highly regulated and controlled by a number of genetic and environmental factors. The mechanism of LtxA action on WBCs varies depending on the type of cell that is being killed, and the protein has been shown to activate numerous cell death pathways in susceptible cells. In addition to serving as an important virulence factor for the bacterium, because of its exquisite specificity and rapid activity, LtxA is also being investigated as a therapeutic agent that may be used to treat diseases such as hematological malignancies and autoimmune/inflammatory diseases. It is our hope that this review will inspire an increased intensity of research related to LtxA and its effect on Aggressive Periodontitis, the disease that led to its initial discovery.

PGE2 inhibits TIL expansion by disrupting IL-2 signalling and mitochondrial function

Expansion of antigen-experienced CD8+ T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer1. Interleukin-2 (IL-2) acts as a key regulator of CD8+ cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability2,3. Therefore, it is essential to comprehend mechanistic barriers to IL-2 sensing in the tumour microenvironment to implement strategies to reinvigorate IL-2 responsiveness and T cell antitumour responses. Here we report that prostaglandin E2 (PGE2), a known negative regulator of immune response in the tumour microenvironment4,5, is present at high concentrations in tumour tissue from patients and leads to impaired IL-2 sensing in human CD8+ TILs via the PGE2 receptors EP2 and EP4. Mechanistically, PGE2 inhibits IL-2 sensing in TILs by downregulating the IL-2Rγc chain, resulting in defective assembly of IL-2Rβ–IL2Rγc membrane dimers. This results in impaired IL-2–mTOR adaptation and PGC1α transcriptional repression, causing oxidative stress and ferroptotic cell death in tumour-reactive TILs. Inhibition of PGE2 signalling to EP2 and EP4 during TIL expansion for ACT resulted in increased IL-2 sensing, leading to enhanced proliferation of tumour-reactive TILs and enhanced tumour control once the cells were transferred in vivo. Our study reveals fundamental features that underlie impairment of human TILs mediated by PGE2 in the tumour microenvironment. These findings have therapeutic implications for cancer immunotherapy and cell therapy, and enable the development of targeted strategies to enhance IL-2 sensing and amplify the IL-2 response in TILs, thereby promoting the expansion of effector T cells with enhanced therapeutic potential.

N6-Methyladenosine Promotes TNF mRNA Degradation In CD4+ T Lymphocytes.

N6-methyladenosine (m6A) is a RNA modification that can regulate post-transcriptional processes including RNA stability, translation, splicing and nuclear export. In CD4+ lymphocytes, m6A modifications have been demonstrated to play a role in early differentiation processes. The role of m6A in CD4+ T cell activation and effector function remains incompletely understood. To assess the role of m6A in CD4+ T lymphocyte activation and function, we assessed the transcriptome-wide m6A landscape of human primary CD4+ T cells by methylated RNA immunoprecipitation (meRIP) sequencing. Stimulation of the T cells impacted the m6A pattern of hundreds of transcripts including tumor necrosis factor (TNF). m6A methylation was increased on TNF mRNA after activation, predominantly in the 3' untranslated region (UTR) of the transcript. Manipulation of m6A levels in primary human T cells, the directly affected the expression of TNF. Furthermore, we identified that the m6A reader protein YT521-B homology domain family-2 (YTHDF2) binds m6A-methylated TNF mRNA, and promotes its degradation. Taken together, this study demonstrates that TNF expression in CD4+ T lymphocytes is regulated via m6A and YTHDF2, thereby providing novel insight into the regulation of T cell effector functions.

Abstract LB119: The immune-modulation of HM16390, firing up the poor tumor microenvironment to induce a potent anti-tumor efficacy

Abstract Immunotherapy, encompassing immune checkpoint blockades (ICBs) and immune stimulators, has become a widespread approach in cancer treatment. However, the effectiveness of these strategies relies significantly on the characteristics of the current tumor microenvironment (TME). This reliance underscores the urgent need for a potent immune modulator capable of inducing a favorable TME, particularly in non-immunogenic cold tumors. Here, we demonstrate that HM16390, a long acting IL-2 analog, has the potential to modify the immunogenicity of the TME by activating, expanding, and recruiting cytotoxic effector cells in cold tumor. In the murine B16F10 melanoma model, following the early upregulated proliferative potential, the proportions of CD8+ T as well as NK cells increased in both blood and tumor. While NK cell frequency initially increased and then recovered, CD8 T cells exhibited a dose-dependent upregulation in the late phase in both blood and tumor. Given the IL-2Rα (CD25) affinity of HM16390, there was an increase in Treg proportions in blood; however, intriguingly, Treg frequency decreased in the tumor. This pattern emphasizes the crucial role of HM16390 in balancing the hyper-activation of peripheral effector cells while simultaneously inducing a profoundly immune-favorable TME. Effector functions were also upregulated in both blood and tumor. Early upregulation of IFN-γ and TNF occurred in both blood and tumor, but the upregulation of granzyme B displayed a sustained expression pattern in the tumor. These immune-modulated features correlated with the exposures of HM16390, particularly noting a negative correlation between Treg down-regulation and Its exposure in blood. The immune modulations of HM16390 were validated in terms of efficacy in the Pancreatic Ductal Adenocarcinoma (PDAC) model. HM16390 was administered subcutaneously to panc02 tumor syngeneic mice via once-a-week administration for 6 weeks, with or without PD-1 combination treatment. HM16390 treatment group was well-tolerated and resulted in a dose-dependent anti-tumor effect. Notably, all mice treated with the highest dose exhibited a complete response. Furthermore, in panc02 syngeneic mice, known for a poor response to ICBs, the combination treatment of HM16390 with mAnti-PD-1 demonstrated synergistic anti-tumor effects. In conclusion, HM16390 demonstrates improved expansion and functions of effector tumor-infiltrating lymphocytes (TILs), correlating with exposure, and exhibits a safe Treg modulation pattern. These modulations culminate in a significant anti-tumor effect and synergies with PD-1 blockade in the B16F10 and PDAC model. Given that both B16F10 melanoma and Panc02 PDAC are recognized as poor immunogenic murine models with low TIL frequency, HM16390 shows promise in modifying the immunogenicity of the TME, thereby activating proper immune responses in preclinical models. Citation Format: Seongju Jeong, Yunjae Kim, Jooyun Byun, Jinyoung Kim, Jaehyuk Choi, Sungmin Bae, Daejin Kim, In Young Choi. The immune-modulation of HM16390, firing up the poor tumor microenvironment to induce a potent anti-tumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB119.

Intracellular acidity impedes KCa3.1 activation by Riluzole and SKA-31.

The unique microenvironment in tumors inhibits the normal functioning of tumor-infiltrating lymphocytes, leading to immune evasion and cancer progression. Over-activation of KCa3.1 using positive modulators has been proposed to rescue the anti-tumor response. One of the key characteristics of the tumor microenvironment is extracellular acidity. Herein, we analyzed how intra- and extracellular pH affects K+ currents through KCa3.1 and if the potency of two of its positive modulators, Riluzole and SKA-31, is pH sensitive. Whole-cell patch-clamp was used to measure KCa3.1 currents either in activated human peripheral lymphocytes or in CHO cells transiently transfected with either the H192A mutant or wild-type hKCa3.1 in combination with T79D-Calmodulin, or with KCa2.2. We found that changes in the intra- and extracellular pH minimally influenced the KCa3.1-mediated K+ current. Extracellular pH, in the range of 6.0-8.0, does not interfere with the capacity of Riluzole and SKA-31 to robustly activate the K+ currents through KCa3.1. Contrariwise, an acidic intracellular solution causes a slow, but irreversible loss of potency of both the activators. Using different protocols of perfusion and depolarization we demonstrated that the loss of potency is strictly time and pH-dependent and that this peculiar effect can be observed with a structurally similar channel KCa2.2. While two different point mutations of both KCa3.1 (H192A) and its associated protein Calmodulin (T79D) do not limit the effect of acidity, increasing the cytosolic Ca2+ concentration to saturating levels eliminated the loss-of-potency phenotype. Based on our data we conclude that KCa3.1 currents are not sensitive the either the intracellular or the extracellular pH in the physiological and pathophysiological range. However, intracellular acidosis in T cells residing in the tumor microenvironment could hinder the potentiating effect of KCa3.1 positive modulators administered to boost their activity. Further research is warranted both to clarify the molecular interactions between the modulators and KCa3.1 at different intracellular pH conditions and to define whether this loss of potency can be observed in cancer models as well.

Immunomodulatory effect of ashwagandha (Withania somnifera(L.) Dunal) and its impact on COVID-19

Ashwagandha (Withania somnifera(L.) Dunal) is an Ayurvedic medicinal herb that has been known for its therapeutic properties for millennia. Ashwagandha contains several bioactive compounds, including withanolides, alkaloids, and saponins. They make ashwagandha a potent adaptogen and a versatile herb that can maintain optimal health and overall well-being. Ashwagandha reduces stress and anxiety, as well as boosts the immune system. Its anti-inflammatory properties treat arthritis, asthma, diabetes, and inflammatory bowel disease. 
 Ashwagandha produces an immunomodulatory effect on natural killer cells, lymphocytes, and leukemia cells. It enhances the activity of natural killer cells, increases lymphocyte function, and induces apoptosis in leukemia cells. However, its mechanism of action still remains understudied. 
 Ashwagandha has an impact on COVID-19: phytochemical withanone blocks or weakens the interaction between S-protein and Angiotensin-converting enzyme 2. Withanoside V and somniferine inhibit viral transcription and replication caused by SARSCoV-2 Mpro. 
 This review explores the potential utilization of ashwagandha in the food industry, i.e., its safety and toxicity, as well as the mechanism behind its immunomodulatory effect.

Double-negative T cells utilize a TNFα–JAK1–ICAM-1 cytotoxic axis against acute myeloid leukemia

AbstractAllogeneic double-negative T cells (DNTs) are a rare T-cell subset that effectively target acute myeloid leukemia (AML) without inducing graft-versus-host disease in an allogeneic setting. A phase 1 clinical trial demonstrated the feasibility, safety, and potential efficacy of allogeneic DNT therapy among patients with relapsed AML. However, the molecular mechanisms of DNT-mediated cytotoxicity against AML remain elusive. Thus, we used a flow cytometry–based high throughput screening to compare the surface molecule expression profile on DNTs during their interaction with DNT-susceptible or -resistant AML cells and identified a tumor necrosis factor α (TNFα)-dependent cytotoxic pathway in DNT-AML interaction. TNFα secreted by DNTs, upon encountering susceptible AML targets, sensitized AML cells to DNT-mediated killing, including those otherwise resistant to DNTs. Mechanistically, TNFα upregulated ICAM-1 on AML cells through a noncanonical JAK1-dependent pathway. DNTs then engaged with AML cells more effectively through an ICAM-1 receptor, lymphocyte function–associated antigen 1, leading to enhanced killing. These results reveal a TNFα–JAK1–ICAM-1 axis in DNT-mediated cytotoxicity against AML to improve therapeutic efficacy.

Abstract 1087: Synergistic mechanisms against pediatric bone sarcoma models: Trabectedin enhances oncolytic virotherapy intratumoral spread and antitumor immune activation

Abstract Osteosarcoma and Ewing sarcoma are the most common pediatric bone malignancies and, despite decades of research, efforts to treat patients with advanced disease remain dismal. To address this inadequacy, we leverage oncolytic herpes simplex virotherapy as a double-edged attack against tumors through 1) tumor cell-specific lysis and 2) antitumor immune stimulation. However, previous trials of oncolytic herpes simplex virotherapy in pediatric sarcomas displayed limited responses, likely due to the observed presence of immunosuppressive monocytes and macrophages. To improve efficacy, we combined oncolytic herpes simplex virotherapy with trabectedin, an FDA-approved DNA-binding agent known to disrupt gene expression and deplete monocytes and macrophages. Surprisingly, we found that the efficacy of this combination far surpassed our predictions, inducing complete and partial regressions in multiple models of Ewing sarcoma and osteosarcoma. To explore potential mechanisms driving this high degree of synergy, we performed single cell RNA sequencing on tumors of mice treated with monotherapy or combination therapy. Interestingly, trabectedin synergized with the oncolytic virotherapy through two unexpected mechanisms. Our analysis revealed that trabectedin increased intratumoral oncolytic virus spread by disrupting expression of the intrinsic antiviral response in human Ewing sarcoma cells. Additionally, trabectedin not only reduced immunosuppressive macrophages but also stimulated cytotoxic granzyme expression in infiltrating T and NK cells in immunocompetent osteosarcoma models. These effector NK and T cells were necessary for the regressions of osteosarcoma allografts treated with trabectedin and oncolytic virotherapy. Thus, trabectedin enhanced both the oncolytic effect of herpes simplex virotherapy and the effector function of cytotoxic lymphocytes that become activated in response to the virus. The combination of trabectedin and oncolytic herpes simplex virotherapy offers the potential to unite these mechanisms against bone tumors to achieve better outcomes for children. Citation Format: Emily Ringwalt, Mark Currier, Andrea Glaspell, Matthew V. Cannon, Chun-Yu Chen, Amy C. Gross, Maren Cam, Pin-Yi Wang, Ryan D. Roberts, Timothy P. Cripe. Synergistic mechanisms against pediatric bone sarcoma models: Trabectedin enhances oncolytic virotherapy intratumoral spread and antitumor immune activation [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 1087.

Abstract 5525: Tissue-resident cytotoxic T cell infiltration predicts metachronous colorectal cancer metastasis

Abstract Background: Identifying patients at high risk for metachronous colorectal cancer metastasis is essential for improving prognosis. The balance between host immune regulation and tumor immune evasion ultimately permits or prevents cancer progression. Lymphocytic infiltration in colorectal cancer can predict long-term clinical outcomes. However, these lymphocytes' origin, subtype and function have yet to be adequately explored. We investigated the association between the development of metastasis and CD8+T cells expressing the integrin protein CD103, a marker of tissue-resident memory T cells. Methods: In this retrospective, case-control matched study, we conducted multiplex immunofluorescence staining of tumor samples from 124 patients with colorectal cancer. Tissue microarrays containing representative cores of the central tumor, invasive margin, and adjacent normal tissue were immunostained for CD3, CD8, CD103, pSMAD3, and cytokeratin, using tyramide signal amplification. Cells were quantified using StrataQuest digital image analysis software, with intratumoral and stromal regions analyzed separately. Kruskal-Wallis one-way analysis of variance with subsequent Dunn’s test for pair-wise comparisons was performed using the Bonferroni method of multiple-comparison correction. Results: Central tumor and invasive margin CD3+ densities were associated with synchronous metastasis. Compared to non-metastatic patients, those who went on to develop metachronous metastasis (n=42) had a low proportion of intra-epithelial CD8+CD103+ T cells at the central tumor (non-metastatic: 32.8%, IQR 15.0-42.7%; metachronous metastasis: 12.9%, IQR 2.08-28.4%; P = 0.013). Similarly, patients with metachronous metastasis had a low proportion of stromal CD8+CD103+ T cells at the invasive margin (non-metastatic: 3.51%, IQR 1.83-6.55%; metachronous metastasis: 1.75%, IQR 0.62-3.72%; P = 0.019). On multivariate Cox regression of histological features, amongst patients with metastasis, significant overall survival prognostic markers included a low proportional CD8+CD103+ T cell infiltration (HR 2.41, 95%CI 1.16-5.01, P = 0.019), mucinous features (HR 4.28, 95%CI 1.98-9.24, P < 0.001), and the presence of perineural invasion (HR 2.75, 95%CI 1.28-5.89, P < 0.001). Conclusion: CD8+CD103+ lymphocytes may protect from the development of colorectal metastasis. Proportional CD8+CD103+ T cell infiltration is a promising prognostic marker in colorectal adenocarcinoma for the development of metachronous metastasis, and, amongst patients with metastasis, it is a prognostic marker of overall survival. Citation Format: Ryan Cohen, Tracey Lee-Pullen, Timothy Miller, Shadi Pirasteh, Cameron Platell, Katie Meehan, Kathy Fuller, Melanie McCoy. Tissue-resident cytotoxic T cell infiltration predicts metachronous colorectal cancer metastasis [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 5525.

Modulating Cholesterol Metabolism via ACAT1 Knockdown Enhances Anti-B-Cell Lymphoma Activities of CD19-Specific Chimeric Antigen Receptor T Cells by Improving the Cell Activation and Proliferation.

CD19-specific CAR-T immunotherapy has been extensively studied for the treatment of B-cell lymphoma. Recently, cholesterol metabolism has emerged as a modulator of T lymphocyte function and can be exploited in immunotherapy to increase the efficacy of CAR-based systems. Acetyl-CoA acetyltransferase 1 (ACAT1) is the major cholesterol esterification enzyme. ACAT1 inhibitors previously shown to modulate cardiovascular diseases are now being implicated in immunotherapy. In the present study, we achieved knockdown of ACAT1 in T cells via RNA interference technology by inserting ACAT1-shRNA into anti-CD19-CAR-T cells. Knockdown of ACAT1 led to an increased cytotoxic capacity of the anti-CD19-CAR-T cells. In addition, more CD69, IFN-γ, and GzmB were expressed in the anti-CD19-CAR-T cells. Cell proliferation was also enhanced in both antigen-independent and antigen-dependent manners. Degranulation was also improved as evidenced by an increased level of CD107a. Moreover, the knockdown of ACAT1 led to better anti-tumor efficacy of anti-CD19 CAR-T cells in the B-cell lymphoma mice model. Our study demonstrates novel CAR-T cells containing ACAT1 shRNA with improved efficacy compared to conventional anti-CD19-CAR-T cells in vitro and in vivo.