Suppressor T Cells Research Articles

Lymphocyte phenotyping in untreated children patients with chronic allergic asthma

This study aimed to isolate and phenotype lymphocytes in untreated children patients with chronic allergic asthma. To reach such aim the study involved (25) patients from children (17 male and 9 female) whom their ages where between (3-10) years, in addition to (15) apparently healthy children (9 male and 6 female) in the same ages involved as control group. The data demonstrated that there was a significant increase in the mean percentages of T-lymphocytes (CD3+ cells) in the peripheral blood of patients (66.75±0.29)**, in comparison with control group (43.58±0.19), a significant increase in the mean percentages of T-helper lymphocytes (CD4+ cells) in the peripheral blood of patients (51.14±0.55), in comparison with control group (39.17±0.23) and the mean percentages of B-lymphocytes (CD20+ cells) was also increased significantly in the peripheral blood of patients (29.63±0.20) when it compared with the mean percentages of the same cells in control group (18.60±0.80). Besides a significant decrease in the mean percentages of T-suppressor lymphocytes (CD8+ cells) in the peripheral blood of patients (11.31±0.05), in comparison with control group (16.42±0.15). Finally the results of this study showed a significant increase in the mean percentages of the ratio of (CD4+ cells/CD8+ cells) in the peripheral blood of patients (55.34±0.41), in comparison with control group (31.25±0.09).

6489 Type 1 Diabetes Mellitus And Multiple Sclerosis: A Case Report Showing The Concurrent Association Of Two Autoimmune Diseases

Abstract Disclosure: P.B. Singh: None. B. Sabates: None. A. Sharifzadeh: None. R.F. Rodriguez: None. Introduction: Both Type 1 Diabetes Mellitus (T1DM) and Multiple Sclerosis (MS) represent persistent autoimmune conditions. T1DM is characterized by the presence of specific autoantibodies targeting pancreatic β-cells. In MS, autoreactive cells mediate a demyelinating inflammatory response directed against the central nervous system. Despite differences in demographics and clinical characteristics, their common root in autoimmunity has led researchers to discover commonalities in genetic, environmental and immunological features. Case Presentation We present a case of a 40-year-old female with medical history of T1DM diagnosed at 7 years of age and MS diagnosed at 32 years of age. She presented to the hospital with clinical features of optic neuritis and symptoms of squeezing ribcage pressure consistent with acute MS exacerbation. After confirmatory neuroimaging, high-dose intravenous corticosteroids were initiated, and Endocrinology services were consulted for inpatient glycemic management. As the patient’s diabetes was treated via continuous subcutaneous insulin infusion (CSII), her pump settings were adjusted to maintain euglycemia during hospitalization. This case is reported to highlight and discuss the association between T1DM and MS. Discussion About 4-5% of the general population is affected by autoimmune disorders, among which T1DM and MS comprise a substantial portion. Multiple studies demonstrate the association and shared etiopathogenesis between T1DM and MS. One study revealed that the prevalence of T1DM is five times higher in patients with MS in comparison to the general population. In another prospective cohort study, individuals with T1DM had a three times higher chance of subsequently developing MS. Additionally, first-degree relatives of MS patients had a roughly 40% higher risk of developing T1DM. Women with T1DM had a 20-fold higher risk of having MS than women without the condition, per another study. As T-cell mediated autoimmune disorders, both T1DM and MS are characterized by autoantigen specific T1-helper cell responses, decreased T-cell suppressor activity, and the presence of various autoantibodies, some of which are seen in both diseases. One study showed that autoreactive T cells could target both pancreatic islet and central nervous system autoantigens in patients with MS, patients with T1DM, and relatives of patients with T1DM. Since MS- and T1DM-associated HLA haplotypes differ between populations, HLA class II alleles per se may not alone be responsible for disease susceptibility. It is suggested that variation at other non-HLA class II loci and/or unknown environmental factors might contribute significantly to the co-occurrence of these 2 diseases. In conclusion, individuals who already have one autoimmune condition are more likely to have other autoimmune conditions, with T1DM and MS being associated more often than expected. Presentation: 6/2/2024

Correlation of peripheral blood monocytic myeloid-derived suppressor cells (M-MDSC) and T-cell receptor (TCR) dynamics with clinical outcomes in patients (pts) with metastatic urothelial carcinoma (mUC) treated with nivolumab (NIVO).

4569 Background: Although PD-1 blockade is active in varied mUC treatment settings, predicting response and overcoming resistance remain unmet needs. We hypothesized that immunosuppressive M-MDSCs (CD14+Lin-/HLA-DRlow/-) and TCR dynamics in tumors and blood may correlate with outcomes from NIVO in pts with platinum-refractory mUC (NCT02553642). Methods: 69 pts with mUC were treated with NIVO 240mg intravenously every 2 weeks (wks). Pre-treatment peripheral M-MDSCs among lineage-negative CD14+ monocytes (%) were estimated by flow cytometry using an algorithm that calculates MDSC frequencies based on HLA-DR mean fluorescence intensity (Kitano et al. 2014). High throughput DNA sequencing of the CDR3 region of the TCR beta chain was performed on baseline tumors (N = 57) and pre and post-treatment (wk 2) peripheral blood mononuclear cells using Adaptive Immunosequencing (Adaptive Biotechnologies). M-MDSC levels and TCR metrics were correlated with clinical outcomes: complete or partial response (CR, PR) vs. stable or progressive disease (SD, PD) by RECIST 1.1, clinical benefit (CR + PR + SD), and progression-free and overall survival (PFS, OS). Groups were compared using Wilcoxon signed rank (paired), Wilcoxon rank sum tests (unpaired), and log-rank tests (time-to-event). Cox proportional hazards and logistic regression models were used to analyze binary and time-to-event outcomes, respectively. Results: Higher pre-treatment M-MDSCs were associated with worse PFS and OS univariably (PFS HR 1.07; 95% CI, 1.01-1.14; p = 0.025; OS HR 1.07; 95% CI, 1.00-1.14; p = 0.038), and after adjustment for liver disease and PD-L1 at baseline (PFS HR 1.12; 95% CI, 1.04-1.21, p = 0.004; OS HR 1.11; 95% CI, 1.03-1.20, p = 0.010). Baseline M-MDSCs did not significantly differ between responders and non-responders, but were significantly lower in patients with clinical benefit (median 12.8 [IQR: 10.7-15.9] vs. median 15.6 [IQR: 13.5-18.3]; p = 0.039), and remained significantly associated after adjustment for PD-L1 score in a multivariable model (OR 0.82; 95% CI, 0.67-0.97; p = 0.037). A higher number of tumor-associated clones in the blood (BTACs) at baseline was associated with response (p = 0.049). Overall, BTACs significantly increased at wk 2 (p < 0.001), and wk 2 values were associated with response (p = 0.003). PFS also significantly differed between BTAC high (high: > median 2,012 clones) and low groups at wk 2, with improved PFS in the high group (log-rank p = 0.026). OS rate for the BTAC high group was 34% vs. 16% for the low group at wk 2, but this did not achieve significance (p = 0.098). Conclusions: Peripheral M-MDSCs may promote resistance to PD-1 blockade in pts with mUC. NIVO stimulated tumor-specific TCR clones in the blood, which correlated with improved response and outcomes. Clinical trial information: NCT02553642 .

Effects of Splenectomy on Natural Killer Cell Levels in β-Thalassemia Major Patients.

In this study, we investigated how splenectomy affects natural killer (NK) cell levels in patients with β-thalassemia major (β-TM). Seventy patients with β-TM (38 splenectomized and 32 nonsplenectomized) and 25 healthy controls were included in this study. The hemogram parameters, ferritin, T lymphocyte, T-helper cell, T-suppressor cell, and NK cell numbers, were measured. The T lymphocyte (CD3+) level was found to be significantly higher in the patient group (p < 0.05). CD3+/CD4+ T lymphocytes were detected to be significantly higher in the patient group (p < 0.05). Although the CD3+/CD4+ T lymphocyte level was significantly higher in the nonsplenectomy group (p < 0.05), this was not the case in the splenectomy group. When the patient and control groups were compared, no significant difference was detected regarding CD3+/CD8+ T lymphocyte levels. CD3-/CD16+CD56+ NK cell level was found to be significantly lower only in the splenectomy group than in the control group (p < 0.05). We found that there was a significant negative correlation between serum ferritin levels and both total lymphocyte (r = -0.617) and CD3+ lymphocyte (r = -0.718) levels in the control group (p < 0.05). A significant negative correlation was detected between serum ferritin levels and CD3-/CD16+CD56+ NK cell levels in the patient group (r = -0.410) (p < 0.05). Splenectomy reduces NK cell levels in patients with β-TM. The negative relationship between ferritin levels and NK cells indicates that ferritin levels should be kept under control in patients with β-TM.

Differential expression of lymphocyte subpopulations in the peripheral blood of patients with COVID-19: Implications for disease severity and prognosis.

To investigate the expression patterns and clinical significance of specific lymphocyte subsets in the peripheral blood of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Between December 2022 and February 2023, a cohort of 165 patients from the First Affiliated Hospital of Guangzhou University of Chinese Medicine were analyzed. The participants represented various stages of coronavirus infection severity: mild, moderate, severe, and critical. Additionally, 40 healthy individuals constituted the control group. The FC 500MPL flow cytometer and associated reagents for flow cytometry. Compared with the healthy control group, activated B lymphocytes witnessed a pronounced increase (p < .05). A significant decrease was observed in the levels of Breg, Cytotoxic T cells or Suppressor T-cell (Tc/s), late-activated T, late-activated Th, and late-activated Tc/s lymphocytes (p < .05). Th, initial Th, initial Tc/s, total Treg, natural Treg, induced Treg, early activated T, and early activated Th lymphocyte levels showed no significant difference (p > .05). As the disease progressed, there was an uptick in midterm activated T lymphocytes (p < .05), while Breg, T, Tc/s, senescent Tc/s, and total senescent T levels dwindled (p < .05). Noteworthy patterns emerged across different groups for B1, T-lymphocytes, Tc/s, B2, CD8+ Treg cells, and other subsets, highlighting variance in immune responses relative to disease severity. When juxtaposed, no significant difference was found in the expression levels of lymphocyte subsets between patients who died and those deemed critically ill (p > .05). Subsets of Treg and B-cells could act as yardsticks for the trajectory of SARS-CoV-2 infection and might have potential in forecasting patient trajectories. A comprehensive evaluation of lymphocyte subsets, especially in real-time, holds the key to discerning the clinical severity in those with COVID-19. This becomes instrumental in monitoring treatment outcomes, tracking disease evolution, and formulating prognostications. Moreover, the results provide a deeper understanding of the cellular immune defense mechanisms against the novel coronavirus infection.

PGE2-EP4 signaling steers cDC2 maturation toward the induction of suppressive T-cell responses.

Dendritic cells (DCs) shape adaptive immunity in response to environmental cues such as cytokines or lipid mediators, including prostaglandin E2 (PGE2). In cancer, tumors are known to establish an enriched PGE2 microenvironment. Tumor-derived PGE2 primes regulatory features across immune cells, including DCs, facilitating tumor progression. PGE2 shapes DC function by providing signaling via its two so-called E-prostanoid receptors (EPs) EP2 and EP4. Although studies with monocyte-derived DCs have shown the importance of PGE2 signaling, the role of PGE2-EP2/EP4 on conventional DCs type 2 (cDC2s), is still poorly defined. In this study, we investigated the function of EP2 and EP4 using specific EP antagonists on human cDC2s. Our results show that EP2 and EP4 exhibit different functions in cDC2s, with EP4 modulating the upregulation of activation markers (CD80, CD86, CD83, MHC class II) and the production of IL-10 and IL-23. Furthermore, PGE2-EP4 boosts CCR type 7-based migration as well as a higher T-cell expansion capacity, characterized by the enrichment of suppressive rather than pro-inflammatory T-cell populations. Our findings are relevant to further understanding the role of EP receptors in cDC2s, underscoring the benefit of targeting the PGE2-EP2/4 axis for therapeutic purposes in diseases such as cancer.

Current status and future of cancer vaccines: A bibliographic study

BackgroundCancer vaccines are an important component of tumour immunotherapy. An increasing number of studies have shown that cancer vaccines have considerable clinical benefits. With the development of tumour precision medicine, cancer vaccines have become important because of their individualised targeting effects. However, few bibliometric studies have conducted comprehensive systematic reviews in this field. This study aimed to assess the scientific output and trends in cancer vaccine research from a global perspective. MethodsWe collected publications on cancer vaccines from the Web of Science Core Collection database, which was limited to articles and reviews in English. Microsoft Excel, VOS Viewer, and CiteSpace V were used for quantitative and visual analyses. ResultsA total of 7807 articles were included. From 1991 to 2022, the number of publications increased annually. The United States had the highest number of articles published in this field (48.28 %), the highest citation frequency (183,964 times), and the highest H-index (182). The National Institutes of Health topped the list with 476 articles. Schlom J had the highest number of published articles (128) and was the main investigator in this field. The journal, Cancer Immunology Immunotherapy, had published the highest number of articles in related fields. In recent years, tumour microenvironment, immune checkpoint inhibitors, particle vaccines, tumour antigens, and dendritic cells have become research hotspots related to cancer vaccines. ConclusionCancer vaccines are a popular research topic in the field of tumour immunotherapy. Related research and publications will enter a boom stage. “Immune checkpoint inhibitors”, “tumour microenvironment” and “dendritic cells” may become future research hotspots, while “T-cell suppressor” is a potential puzzle to be solved.

Candida-induced granulocytic myeloid-derived suppressor cells are protective against polymicrobial sepsis.

Polymicrobial intra-abdominal infections are serious clinical infections that can lead to life-threatening sepsis, which is difficult to treat in part due to the complex and dynamic inflammatory responses involved. Our prior studies demonstrated that immunization with low-virulence Candida species can provide strong protection against lethal polymicrobial sepsis challenge in mice. This long-lived protection was found to be mediated by trained Gr-1+ polymorphonuclear leukocytes with features resembling myeloid-derived suppressor cells (MDSCs). Here we definitively characterize these cells as MDSCs and demonstrate that their mechanism of protection involves the abrogation of lethal inflammation, in part through the action of the anti-inflammatory cytokine interleukin (IL)-10. These studies highlight the role of MDSCs and IL-10 in controlling acute lethal inflammation and give support for the utility of trained tolerogenic immune responses in the clinical treatment of sepsis.

The immune checkpoint VISTA is associated with prognosis in patients with malignant uveal melanoma.

Uveal melanoma (UM) is a rare yet deadly tumor. It is known for its high metastatic potential, which makes it one of the most aggressive and lethal cancers. Recently, immune checkpoints such as Programmed cell Death protein-1 (PD1) and Cytotoxic T-Lymphocyte-Associated significantly increasing patient survival in multiple human cancers, especially cutaneous melanoma. However, patients with UMs were excluded from these studies because of their molecular characteristics, which tend to be widely different from those of cutaneous melanoma. This study aimed to analyze the expression of V domain Ig Suppressor T-cell Activation (VISTA), a novel immune checkpoint, to evaluate its prognosis significance and its correlation with PD1 and CTLA-4. Evaluation of VISTA, CTLA-4, and PD1 expression was performed through TCGA database analysis and immunohistochemistry using two independent cohorts with primary malignant UM. Our results showed that VISTA expression was associated with tumor aggressiveness, T cell exhaustion, and the shortest median overall survival among patients. Surprisingly, PD1 protein expression was negative in all patients, whereas CTLA-4 expression was high in patients with advanced stages. Our findings suggest that VISTA may be a prognostic marker and an attractive treatment strategy for immunotherapy in patients with UM. Exploring its expression profile may predict response to immunotherapy and may lead to the improvement of precision therapy in malignant uveal melanoma patients.

Microenvironmental regulation of T-cells in pulmonary hypertension.

In pulmonary hypertension (PH), pulmonary arterial remodeling is often accompanied by perivascular inflammation. The inflammation is characterized by the accumulation of activated macrophages and lymphocytes within the adventitial stroma, which is comprised primarily of fibroblasts. The well-known ability of fibroblasts to secrete interleukins and chemokines has previously been implicated as contributing to this tissue-specific inflammation in PH vessels. We were interested if pulmonary fibroblasts from PH arteries contribute to microenvironmental changes that could activate and polarize T-cells in PH. We used single-cell RNA sequencing of intact bovine distal pulmonary arteries (dPAs) from PH and control animals and flow cytometry, mRNA expression analysis, and respirometry analysis of blood-derived bovine/human T-cells exposed to conditioned media obtained from pulmonary fibroblasts of PH/control animals and IPAH/control patients (CM-(h)PH Fibs vs CM-(h)CO Fibs). Single-cell RNA sequencing of intact bovine dPAs from PH and control animals revealed a pro-inflammatory phenotype of CD4+ T-cells and simultaneous absence of regulatory T-cells (FoxP3+ Tregs). By exposing T-cells to CM-(h)PH Fibs we stimulated their proinflammatory differentiation documented by increased IFNγ and decreased IL4, IL10, and TGFβ mRNA and protein expression. Interestingly, we demonstrated a reduction in the number of suppressive T-cell subsets, i.e., human/bovine Tregs and bovine γδ T-cells treated with CM-(h)PH-Fibs. We also noted inhibition of anti-inflammatory cytokine expression (IL10, TGFβ, IL4). Pro-inflammatory polarization of bovine T-cells exposed to CM-PH Fibs correlated with metabolic shift to glycolysis and lactate production with increased prooxidant intracellular status as well as increased proliferation of T-cells. To determine whether metabolic reprogramming of PH-Fibs was directly contributing to the effects of PH-Fibs conditioned media on T-cell polarization, we treated PH-Fibs with the HDAC inhibitor SAHA, which was previously shown to normalize metabolic status and examined the effects of the conditioned media. We observed significant suppression of inflammatory polarization associated with decreased T-cell proliferation and recovery of mitochondrial energy metabolism. This study demonstrates how the pulmonary fibroblast-derived microenvironment can activate and differentiate T-cells to trigger local inflammation, which is part of the vascular wall remodeling process in PH.

IMMU-21. ELUCIDATING THE CELLULAR MECHANISMS OF THERAPEUTIC BENEFIT UNDERLYING ADOPTIVE CELLULAR THERAPY IN MODELS OF GLIOMA

Abstract Among pediatric cancers, malignancies of the brain carry significant morbidity and mortality, harboring dismal prognosis and poor outcomes. Our group has previously shown that adoptive cellular therapy (ACT) provides therapeutic benefit against central nervous system (CNS) malignancies, including medulloblastoma and high-grade glioma. In this study, we characterized cell cycling differences of immune sub-populations in peripheral lymphoid and tumor tissue compartments in vivo. ACT was conducted in orthotopic KR158 luciferase tumor-bearing mice, a syngeneic murine glioma model. Five days following intracranial implantation of tumor cells, mice were treated with ACT which included the following elements: total body irradiation, hematopoietic stem cell transplantation, one dose of tumor-activated splenocytes and three weekly doses of dendritic cells that had been electroporated with tumor-derived ribonucleic acid. One week after the completion of ACT, bromodeoxyuridine (BRDU) was administered to mice 12-hours prior to tissue collection and flow cytometry was utilized to measure the level of BRDU incorporation. 7-aminoactinomycin-D was used in conjunction with BRDU to provide insight into all phases of the cell cycle. We observed significant differences in cycling populations of myeloid derived suppressor cells (MDSC) and T-cells. In ACT-treated-mice, MDSCs found in secondary lymphoid tissues were significantly more proliferative. In the tumor microenvironment (TME), proliferating MDSCs were significantly reduced compared to mice that did not receive treatment. Frequencies of proliferating CD4+ and CD8+ T-cells were significantly increased in cervical lymph node and TME but reduced in spleen. These findings suggest that ACT alters immune cycling in peripheral lymphoid tissues and TME to potentially promote antitumor T-cell responses and minimize MDSC-mediated immunosuppression. While ACT-mediated alterations to immune cell cycling are likely a major contributor to the therapy’s benefit, it is unlikely to be the sole mechanism. Further exploration into other functional pathways, namely migration, is needed to explain changes to immune populations following ACT.

A phase 2, two-stage study of avelumab and axitinib in patients with mismatch repair–proficient (MMR-P) recurrent or persistent endometrial cancer (EC).

TPS5628 Background: Despite significant strides in understanding the molecular pathogenesis of EC, there remain few effective therapies for recurrent disease. Deeper insight into the roles of disordered tumor vasculature and HIF1α- and VEGF-mediated immunosuppressive effects on myeloid-derived suppressor cells, T-cells, and PD-L1 expression contributed to the development of new targeted regimens. By inhibiting VEGF receptor (VEGFR) and PD-L1 signaling, immunologically “cold” tumors may become inflamed. The combination of the anti-PD-L1 antibody avelumab with axitinib, an inhibitor of VEGFR 1-3 and PDGFR with more potent IC50 inhibitory activity than lenvatinib, has also shown synergistic activity and is FDA approved as first line treatment for patients with renal cell cancer. We therefore hypothesized that this combination would be well tolerated and efficacious in recurrent MMR-P EC. Objectives:This is a non-randomized two-stage phase 2 study in patients with MMR-P EC evaluating the activity of combined avelumab and axitinib, as assessed by the co-primary endpoints of (1) frequency of patients surviving progression-free for at least 6 months (PFS6), and (2) the objective response rate (ORR) as measured by RECIST 1.1. Methods: Patients must have MMR-P EC and have received at least one chemotherapeutic regimen, with no upper limit on the number of prior lines received. Prior use of immune checkpoint inhibitors (ICI) is excluded. Eligible patients received avelumab 800 mg IV every 2 weeks and axitinib 5 mg orally twice daily until disease progression or unacceptable toxicity. In the first stage of the study, 16 patients were enrolled; if there were ≥2 objective responses or ≥2 PFS6 responses, accrual continued to the second stage with enrollment of an additional 19 patients. The combination of avelumab/axitinib would be considered worthy of further study if overall there were ≥4 objective responses or ≥8 PFS6 responses. Results: As of the data-cutoff in September 2022, a total of 28 patients had received study treatment; one patient withdrew from the study due to toxicity, prior to her first radiographic assessment. The median number of prior lines was 1 (range 1-4). Median follow-up was 12.7 months. Of the 28 patients receiving study treatment, eleven patients (39.3%, 95% CI 21.5%-59.4%) achieved a PR [11/28; 8 confirmed PR (28.6%) and 3 unconfirmed PR (10.7%)]. An additional 39.3% (11/28) had stable disease as best response. Median PFS was 7.3 months (95% CI 3.9-9.0). PFS6 was 59.3% (95% CI 35.7%-76.7%) and at 6 months, 10 patients were still alive and progression-free. Updated efficacy data and safety data will be reported at the time of the meeting. Conclusions: With 8 confirmed PRs and 10 PFS6 responses, the co-primary endpoints were met and the combination of avelumab/axitinib is considered worthy of further study in this population of MMR-P EC. Clinical trial information: NCT02912572 .

Incorporation of a TGF-β2-inhibiting oligodeoxynucleotide molecular adjuvant into a tumor cell lysate vaccine to enhance antiglioma immunity in mice.

Transforming growth factor β2 (TGF-β2), also known as glioma-derived T-cell suppressor factor, is associated with the impairment of tumor immune surveillance. Therefore, blocking TGF-β2 signaling probably be a feasible strategy to develop a novel type of adjuvant for glioma vaccines to enhance antitumor immunity. A TGF-β2 inhibitory oligodeoxynucleotide, TIO3, was designed with sequences complementary to the 3' untranslated region of TGF-β2 mRNA. The expression of TGF-β2 and MHC-I was detected by qPCR, western and flow cytometry in vitro. All the percentage and activation of immune cells were detected by flow cytometry. Subsequently, TIO3 was formulated with Glioma cell lysate (TCL) and investigated for its antitumor effects in GL261 murine glioma prophylactic and therapeutic models. TIO3 could efficiently downregulate the expression of TGF-β2 while increase the MHC-I's expression in GL261 and U251 glioma cells in vitro. Meanwhile, TIO3 was detected in mice CD4+ T, CD8+ T, B and Ly6G+ cells from lymph nodes after 24 hours incubation. Moreover, TCL+TIO3 vaccination significantly prolonged the survival of primary glioma-bearing mice and protected these mice from glioma re-challenge in vivo. Mechanistically, TCL+TIO3 formulation strongly evoke the antitumor immune responses. 1) TCL+TIO3 significantly increased the composition of CD4+ and CD8+ T cells from draining lymph nodes while promoted their IFN-γ production and reduced the expression of TGF-β2 and PD1. 2) TCL+TIO3 activated the NK cells with the elevation of CD69 or NKG2D expression and PD1 reduction. 3) TCL+TIO3 increased the glioma-specific lysis CTLs from spleen. 4) TCL+TIO3 downregulated PD-L1 expression in glioma tissues and in Ly6G+ cells among glioma-infiltrating immune cells. TIO3 is a promising adjuvant for enhancing TCL-based vaccines to produce a more vigorous and long-lasting antitumor response by interfering with TGF-β2 expression.

The introduction of LAG-3 checkpoint blockade in melanoma: immunotherapy landscape beyond PD-1 and CTLA-4 inhibition.

Despite major advances with immunotherapy and targeted therapy in the past decade, metastatic melanoma continues to be a deadly disease for close to half of all patients. Over the past decade, advancement in immune profiling and a deeper understanding of the immune tumor microenvironment (TME) have enabled the development of novel approaches targeting and a multitude of targets being investigated for the immunotherapy of melanoma. However, to date, immune checkpoint blockade has remained the most successful with programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors, alone or in combination, yielding the most robust and durable clinical outcome in patients with metastatic melanoma. The highest rate of durable responses is achieved with the combination with PD-1 and CTLA-4 inhibition, and is effective in a variety of settings including brain metastases; however, it comes at the expense of a multitude of life-threatening toxicities occurring in up to 60% of patients. This has also established melanoma as the forefront of immuno-oncology (IO) drug development, and the search for novel checkpoints has been ongoing with multiple relevant targets including T-cell immunoglobulin and mucinodomain containing-3 (TIM-3), LAG-3, V-domain immunoglobulin suppressor T-cell activation (VISTA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), among others. Lymphocyte activation gene-3 (LAG-3), which is a co-inhibitory receptor on T cells that suppress their activation, has revolutionized immunomodulation in melanoma. The 'game changing' results from the RELATIVITY-047 trial validated LAG-3 blockade as a relevant biological target and established it as the third clinically relevant immune checkpoint. Importantly, LAG-3 inhibition in combination with PD-1 inhibition offered impressive efficacy with modest increases in toxicity over single agent PD-1 inhibitor and has been U.S. Food and Drug Administration approved for the first-line therapy of patients with metastatic melanoma. The efficacy of this combination in patients with untreated brain or leptomeningeal metastases or with rare melanoma types, such as uveal melanoma, remains to be established. The challenge remains to elucidate specific mechanisms of response and resistance to LAG-3 blockade and to extend its benefits to other malignancies. Ongoing trials are studying the combination of LAG-3 antibodies with PD-1 inhibitors in multiple cancers and settings. The low toxicity of the combination may also allow for further layering of additional therapeutic approaches such as chemotherapy, oncolytic viruses, cellular therapies, and possibly novel cytokines, among others.

The past, present, and future of targeted therapeutic approaches in patients with diffuse pleural mesotheliomas.

Despite our growing understanding of the genomic landscape of diffuse pleural mesotheliomas (DPM), there has been limited success in targeted therapeutic strategies for the disease. This review summarizes attempts to develop targeted therapies in DPM, focusing on the following targets being clinically explored in recent and ongoing clinical trials: vascular endothelial growth factor, mesothelin, BRCA1-associated protein 1, Wilms tumor 1 protein, NF2/YAP/TAZ, CDKN2, methylthioadenosine phosphorylase, v-domain Ig suppressor T-cell activation, and argininosuccinate synthetase 1. Although preclinical data for these targets are promising, few have efficaciously translated to benefit our patients. Future efforts should seek to expand the availability of preclinical models that faithfully recapitulate DPM biology, develop clinically relevant biomarkers, and refine patient selection criteria for clinical trials.

Development of a modularized aptamer targeting the nuclear T-cell suppressor PAC1.

Aptamers associated with cancer targeting therapy are commonly focused on cell membrane proteins; however, the study of intracellular, particularly, nuclear proteins is limited. The nuclear phosphatase PAC1 has been reported to be a potential T cell-related immunotherapeutic target. Here, we identified an aptamer, designated as PA5, with high affinity and specificity for PAC1 through the systematic evolution of ligands by exponential enrichment (SELEX) procedure. We then developed a dual-module aptamer PAC1-AS consisting of a cell-internalizing module and a targeting module, which can recognize PAC1 in the nucleus under physiological conditions. This modularized aptamer raises the possibility of manipulating endosomes and provides insights into the exploration and development of an efficient cancer immunotherapy approach.

EP16.01-028 Immunomodulatory Effects of Cryoablation Combined With Immune Checkpoint Inhibitors in a Murine Lung Cancer Model

As part of our research on cryoablation, a combination with immune checkpoint inhibitors (ICIs), such as inhibitors of the programmed cell death 1 (PD-1) receptor and its ligand, programmed cell death 1-ligand 1 (PD-L1), to disrupt the immunosuppressive tumor microenvironment has proven a beneficial effect on enhancing immune response. We specifically addressed myeloid-derived suppressor cells (MDSCs) and T-cell immunity, which are thought to play an important role in the formation of the tumor microenvironment.

Alpha-fetoprotein: Immunomodulation in autoimmune diseases during pregnancy and puerperium stages

Alpha-fetoprotein (AFP) has long been associated with regulation and modulation of the immune system in a variety of mammals. In the last several decades, AFP has been linked to autoimmune diseases (ADs) during both pregnancy and in non-gestational disorders via an immunomodulatory function. The course of ADs are highly influenced by soluble factors such as cytokines, chemokines, interleukins, hormones, kinins, growth factors, proteins such as AFP, and various T-cells generated from the immune response. Such factors appear to serve as protective or ameliorating agents during the induction effector stages of the immune response. Immunomodulatory activities of AFP are known to affect: 1) induction of T-cell suppressor activity; 2) down-regulating dendritic-like cell antigen expression; and 3) impairing the function of macrophages and T-cells. Some factors may even be involved in blocking the rejection of the embryo/fetus as an allograft in the mother at the initiation of pregnancy. Thus, the present report reviews the immunomodulation function of AFP during the course of autoimmune disease utilizing AD disorders such as: myasthenia gravis, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, autoimmune liver disorders, diabetes, thyroiditis, and others.

Abstract P3064: Immunoengineered Tantalum Carbide Mxene Quantum Dots For Prevention Of Transplant Vasculopathy

Transplant vasculopathy is an aggressive form of atherosclerosis that manifests uniquely in transplanted hearts, lungs, and kidneys. Recently, immunoengineered transition metal carbides, or MXenes, have demonstrated unique immunomodulatory properties and this can potentially be leveraged to prevent transplant vasculopathy. Here, we present the synthesis, characterization and application of novel zero-dimensional tantalum carbide (Ta 4 C 3 T x ) MXene quantum dots (MQDs) for immunomodulation. A facile hydrofluoric acid-free etching protocol was developed to synthesize zero-dimensional Ta 4 C 3 T x MQDs from Ta 4 AlC 3 MAX phase. The resultant MQDs are 3 to 7 nm in diameter and are surface modified with carboxyl, hydroxyl, and amine functional groups for biological interactions. Immunomodulation was assessed in vitro through co-cultures of human umbilical vein endothelial cells (ECs) and peripheral blood mononuclear cells. We found that MQDs interact with activated human ECs in vitro to reduce activation and pro-inflammatory Th1 polarization of allogeneic CD4 + lymphocytes. Mechanistically, we showed using quantitative PCR that treatment with MQDs significantly increased endothelial surface expression of the T-cell co-inhibitory molecule PD-L1 and decreased the co-stimulatory molecule CD86. Furthermore, exploratory bulk RNA-sequencing of co-cultured lymphocytes showed decreases in the immunologic signatures of naïve T-cells and increases in the immunologic signatures of CD25 + regulatory T-cells, suggesting activation of this suppressive T-cell population. Finally, when applied in an in vivo rat model of transplant vasculopathy, treatment with MQDs reduced lymphocyte infiltration and preserved medial smooth muscle cell integrity within transplanted aortic segments. These findings suggest that these novel MQDs have potential as an effective treatment to ameliorate transplant vasculopathy.

The role of immunological factors in the development of abnormal uterine bleeding in women of reproductive age with extragenital disorders

The aim of the study was to assess the role of immunological factors in the development of abnormal uterine bleeding in women of reproductive age with extragenital disorders.&#x0D; Materials and methods. The study involved 100 women with abnormal uterine bleeding and accompanying extragenital disorders (main group) and 50 somatically healthy women (control group). Autoimmune antibodies to platelets, phagocytic activity of neutrophil granulocytes, concentration of circulating immune complexes (CICs), total level of membranotropic cytotoxic factors, content of CD4+T-helper subpopulations and cytotoxic CD8+T-killer lymphocytes were evaluated as immunological markers.&#x0D; Results of the study. The study showed that thrombocytopenia, caused by the presence of autoimmune antibodies to their own platelets, can be one of the pathogenic factors of bleeding in women with AUB. In 41 % of women with AUB, phagocytic reactions were found to be intense, which was expressed by an increase in chemotaxis and adhesion functions, and in 46 % of women by an increase in the absorption capacity of phagocytes. In the main group, 48 % of the examined women had insufficient phagocyte enzymatic activity, which was evidenced by a decrease in the index of completion of phagocytosis. In 79 % of women of the main group, violations of the formation and elimination of circulating immune complexes were detected. The formation of low-molecular-weight CICs in 82 % of women of this cohort contributed to the induction of autoimmune reactions. The total content of membranotropic cytotoxic factors, which was evaluated according to the lymphocytotoxic test, exceeded the reference values in 88 % of women of the main group. In the main group, the average content of CD4+ T-helpers was 23 % lower, and the content of suppressor CD8+ T-lymphocytes was twice as low compared to the control group, resulting in a significant increase in the immunoregulatory index by 30 %.&#x0D; Conclusion. The women of the main group with abnormal uterine bleeding were found to have a violation of the functional activity of cellular factors of innate immunity, accompanied by changes in the absorption and digestive capacity of phagocytic cells. Assessment of secondary adaptive reactions showed induction of humoral sensitization and formation of autoimmune reactions (presence of antiplatelet autoantibodies, increase in CICs and LCT, decrease in the subpopulation of CD8+-suppressor T-lymphocytes). The detected violations indicate the pathogenic role of immunological reactions in women with abnormal uterine bleeding