anti-CD3 Antibody Research Articles

CD14 blockade preserves left ventricular structure and systolic function in a murine model of ST-elevation myocardial infarction

Abstract Background Cluster of differentiation-14 (CD14) facilitates the excessive pro-inflammatory monocyte-macrophage response to myocardial injury. Both acute and chronic infiltration of pro-inflammatory macrophages are implicated in the immunological progression of ischemic heart failure. However, investigation of clinically practicable strategies of CD14 blockade are yet to be reported. Purpose This fully blinded and randomised preclinical study evaluated the efficacy of a neutralising anti-CD14 antibody given at reperfusion in a murine model of reperfused ST-elevation myocardial infarction (STEMI) with key clinical features. Methods Large anterior STEMI was induced in 48 adult mice by left anterior descending coronary artery occlusion for 1 h prior to reperfusion and randomisation to receive anti-CD14 antibody, isotype control (IgG2a) or saline weekly for four weeks (independently blinded). Outcome measures included functional assessments by 9.4T cardiac magnetic resonance (CMR) imaging and ultra-high-resolution echocardiography at 21- and 28-days post-STEMI, respectively. Results Multi-plane short axis CMR at 21-days post-STEMI revealed greater left ventricular (LV) ejection fraction in the anti-CD14 antibody-treated group compared with saline- and isotype-treated controls (30±1 vs 19±1 and 20±1 %, respectively, p<0.001; Figure 1A). CMR also revealed reduced LV dilatation with anti-CD14-treatment compared to control groups (76±5 vs 102±8 and 107±7 µl EDV in saline- and isotype-treated controls, respectively, p<0.05). Parasternal long axis echocardiography at 28 days post-STEMI confirmed that anti-CD14 antibody treatment was associated with greater LV systolic function compared to saline and isotype controls (30±1 vs 24±1 and 25±2 % EF, respectively, p<0.05; Figure 1B). Preservation of LV end-diastolic (86±4 vs 111±6 and 101±5 µl, p<0.01) and end-systolic (61±3 vs 84±5 and 77±5 µl, p<0.01) volumes was also observed with anti-CD14 treatment. Global longitudinal strain (GLS) of the LV was also significantly greater at 28 days post-STEMI with anti-CD14 treatment relative to saline and isotype controls (-8.5±0.4 vs -6.8±0.3 and -6.6±0.4 %, respectively, p<0.05). Conclusion(s) The findings of this fully blinded and randomised preclinical study provide evidence of a clinically practicable strategy of CD14 blockade initiated at reperfusion to mitigate progressive LV systolic dysfunction and dilatation post-STEMI.Figure 1.Functional outcome measures

Selenopolysaccharide Isolated from Lentinula edodes Mycelium Affects Human T-Cell Function

Lentinula edodes polysaccharides are natural immunomodulators. SeLe30, analyzed in this study, is a new mixture of selenium-enriched linear 1,4-α-glucans and 1,3-β- and 1,6-β-glucans isolated from L. edodes mycelium. In the present study, we evaluated its immunomodulatory properties in human T cells. Peripheral blood mononuclear cells (PBMCs) and T cells were isolated from healthy donors’ buffy coats. The effects of SeLe30 on CD25, CD366, and CD279 expression, the subsets of CD8+ T cells, and IFN-γ, IL-6, and TNF-α production were analyzed. SeLe30 downregulated CD25, CD279, and CD366 expression on T cells stimulated by the anti-CD3 antibody (Ab) and upregulated in unstimulated and anti-CD3/CD28-Abs-stimulated T cells. It increased the percentage of central memory CD8+ T cells in unstimulated PBMCs and naïve and central memory T cells in anti-CD3-Ab-stimulated PBMCs. SeLe30 decreased the number of central memory and naïve CD8+ T cells in anti-CD3/CD28-stimulated T cells, whereas, in PBMCs, it reduced the percentage of effector memory CD8+ T cells. Moreover, SeLe30 upregulated cytokine production. SeLe30 exhibits context-dependent effects on T cells. It acts on unstimulated T cells, affecting their activation while increasing the expression of immune checkpoints, which sensitizes them to inhibitory signals that can silence this activation. In the case of a lack of costimulation, SeLe30 exhibits an inhibitory effect, reducing T-cell activation. In cells stimulated by dual signals, its effect is further enhanced, again increasing the “safety brake” of CD366 and CD279. However, the final SeLe30 effect is mediated by its indirect impacts by altering interactions with other immune cells.

Repetitive transcranial magnetic stimulation alleviates motor impairment in Parkinson’s disease: association with peripheral inflammatory regulatory T-cells and SYT6

BackgroundRepetitive transcranial magnetic stimulation (rTMS) has been used to treat various neurological disorders. However, the molecular mechanism underlying the therapeutic effect of rTMS on Parkinson’s disease (PD) has not been fully elucidated. Neuroinflammation like regulatory T-cells (Tregs) appears to be a key modulator of disease progression in PD. If rTMS affects the peripheral Tregs in PD remains unknown.MethodsHere, we conducted a prospective clinical study (Chinese ClinicalTrials. gov: ChiCTR 2100051140) involving 54 PD patients who received 10-day rTMS (10 Hz) stimulation on the primary motor cortex (M1) region or sham treatment. Clinical and function assessment as well as flow cytology study were undertaken in 54 PD patients who were consecutively recruited from the department of neurology at Zhujiang hospital between September 2021 and January 2022. Subsequently, we implemented flow cytometry analysis to examine the Tregs population in spleen of MPTP-induced PD mice that received rTMS or sham treatment, along with quantitative proteomic approach reveal novel molecular targets for Parkinson's disease, and finally, the RNA interference method verifies the role of these new molecular targets in the treatment of PD.ResultsWe demonstrated that a 10-day rTMS treatment on the M1 motor cortex significantly improved motor dysfunction in PD patients. The beneficial effects persisted for up to 40 days, and were associated with an increase in peripheral Tregs. There was a positive correlation between Tregs and motor improvements in PD cases. Similarly, a 10-day rTMS treatment on the brains of MPTP-induced PD mice significantly ameliorated motor symptoms. rTMS reversed the downregulation of circulating Tregs and tyrosine hydroxylase neurons in these mice. It also increased anti-inflammatory mediators, deactivated microglia, and decreased inflammatory cytokines. These effects were blocked by administration of a Treg inhibitor anti-CD25 antibody in MPTP-induced PD mice. Quantitative proteomic analysis identified TLR4, TH, Slc6a3 and especially Syt6 as the hub node proteins related to Tregs and rTMS therapy. Lastly, we validated the role of Treg and rTMS-related protein syt6 in MPTP mice using the virus interference method.ConclusionsOur clinical and experimental studies suggest that rTMS improves motor function by modulating the function of Tregs and suppressing toxic neuroinflammation. Hub node proteins (especially Syt6) may be potential therapeutic targets.Trial registrationChinese ClinicalTrials, ChiCTR2100051140. Registered 15 December 2021, https://www.chictr.org.cn/bin/project/edit?pid=133691Graphical rTMS is a safe and non-invasive method for Parkinson's disease. In this study, we showed the proportion of CD4+CD25+CD127- regulatory T-cells (Tregs) in the peripheral blood was significantly increased after rTMS treatment. Similar effects of rTMS treatment were verified in MPTP-induced PD mice. Proteomic analysis and RNA interference analyses identified TLR4, TH, Slc6a3 and especially Syt6 as hub node proteins that can be modulated by rTMS therapy in PD.

How Co-Stimulatory/Inhibitory Molecules Vary Across Immune Cell Subtypes in the Severity of Systemic Lupus Erythematosus Compared to Controls

Background: Co-stimulatory and co-inhibitory molecules are critical to T cell responses and involved in the pathogenesis of systemic lupus erythematosus (SLE). This study aimed to comprehensively analyze the surface expression of these molecules in various phenotypic immune cells, comparing the differences between various levels of the severity in SLE and control groups. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated using Ficoll-Paque from blood samples of severe SLE patients (treatment with immunosuppressants), mild SLE patients (excluding those with persistent proteinuria or thrombocytopenia), and healthy controls (n = 10 each). PBMCs were stimulated for 48 h. The cells were stained with anti-CD3, CD4, CD28, PD-1, and CTLA-4 antibodies and analyzed by flow cytometry. Differences between groups were assessed using the Kruskal–Wallis test and Mann–Whitney U-test, with median values and statistical significance (p < 0.05) reported. Results: The results showed that CD28 expression was significantly higher in SLE patients compared to controls, with the highest levels in mild SLE. However, CD3+ CD28+ and CD4+ CD28+ cells were more prevalent in controls (p = 0.032 and 0.017, respectively). Mild SLE patients exhibited the highest CTLA-4 expression, with significant differences from severe SLE and controls (p = 0.030 and 0.037, respectively). PD-1 expression was lowest in severe SLE but highest in mild SLE within CD3+ CD4+ cells (p = 0.001). After 48 h of activation, CD4+ CTLA4+ and CD3+ CTLA4+ expression levels were significantly higher in controls compared to SLE groups. Conclusions: Our study highlighted that the expression of CD28, CTLA-4, and PD-1 in lymphocytes and specific T cell subsets was various according the severity of SLE in patients, underscoring their roles in disease pathogenesis.

Abstract A031: Unhelpful CD4 help: Removal of conventional CD4+ T cells promotes priming of tumor antigen-specific CD8 T cells in the context of CD4-depletion therapy

Abstract Preclinical and clinical studies have used antibodies to deplete CD4-expressing cells to promote anti-tumor immunity. Specifically, a monoclonal anti-CD4 antibody (anti-CD4) has been employed to remove FOXP3+ CD4+ regulatory T cells (Tregs), which are known to impede anti-tumor immunity. Our previous studies demonstrated that administering anti-CD4 during B16 melanoma tumor growth in mice leads to the generation of tumor Ag-specific CD8 T cells that disseminate and form memory following surgical tumor excision. However, the importance of co-depleting other CD4-expressing cell compartments for anti-CD4 treatment efficacy are unknown. We utilized flow cytometry and single-cell RNA sequencing (scRNAseq) to evaluate the primary response of tumor Ag-specific CD8 T cells (pmel) in B16 melanoma tumor bearing mice treated with anti-CD4. Responses were compared to those induced by anti-PD1 and anti-CTLA4 dual immune checkpoint blockade (ICB). To determine the importance of homeostatic space in priming, homeostatic expansion and priming were decoupled, and neutralizing antibodies were administered. Treg-depleted (Foxp3-DTR) mice were used for comparison, and Batf3-/- mice and IL-2R blocking antibodies were used to determine requirements for CD8 T cell priming. Finally, scRNAseq was conducted on CD4 T cells from human melanoma tumors previously treated with ICB to characterize transcriptional properties of intratumoral CD4 T cells. Compared to ICB, anti-CD4 treatment elicited a more robust, disseminated, and persistent primary tumor Ag-specific CD8 T cell response. ScRNAseq revealed that anti-CD4 treatment induced more stem-like (TCF1+) memory precursor cells, whereas ICB induced more differentiated effector (Gzmb+) cells. Removal of homeostatic space or blockade of IL-7R and IL-15 during priming did not diminish pmel responses in anti-CD4 treated mice, indicating that homeostatic space was not required. Importantly, pmel cells were shown to produce their own IL-2, and pmel priming was significantly lower after IL-2 receptor blockade, suggesting dependence on autocrine IL-2 signals. Using DT-treated FOXP3-DTR mice, we found that targeted Treg depletion was insufficient for the pmel priming that disseminated and formed memory, indicating that total CD4 T cell depletion was required for this systemic response. Depletion of total CD4 T cells uniquely increased cDC1 proportions in tumor-draining LNs as well as their expression of CD86. However, treatment of tumor-bearing RAG-/- mice with anti-CD4 confirmed that depletion of CD4-expressing APC compartments does not contribute to anti-CD4 treatment efficacy. ScRNAseq of CD4 T cells from human melanoma tumors showed dominance of Tr1-like cells and other subsets without transcriptional evidence of helper differentiation, despite prior ICB. In mice, combination of anti-CD4 with dual ICB restored the systemic response of tumor-specific CD8 T cells. This study underscores the importance of eliminating conventional CD4 T cells in tumor-bearing hosts to elicit systemic primary and memory CD8 T cell responses. Citation Format: Christo P. C. Dragnev, Delaney E. Ramirez, Tyler G. Searles, Nathaniel Spicer, TIffany Chen, J. Louise Lines, Aaron R. Hawkes, Wilson L. Davis III, Asmaa Mohamed, Keisuke Shirai, Joesph D. Phillips, Pamela C. Rosato, Yina H. Huang, Mary Jo Turk. Unhelpful CD4 help: Removal of conventional CD4+ T cells promotes priming of tumor antigen-specific CD8 T cells in the context of CD4-depletion therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr A031.

Dynamics of CD4+ and CD8+ Lymphocytic Inflammatory Infiltrates in Lupus Nephritis.

Lupus nephritis (LN) is a common clinical manifestation of systemic lupus erythematosus (SLE). Our study aims to quantitatively analyze CD4+ and CD8+ lymphocytes in different areas and LN classes and describe a specific distribution pattern that is correlated with the severity of LN-specific lesions. In total, 53 LN renal biopsies were immunohistochemically investigated using anti-CD4 and anti-CD8 antibodies. T lymphocytes were counted in 3 areas, including intraglomerular, periglomerular, and interstitial regions. The severity of glomerular and tubulo-interstitial lesions was assessed using an original semi-quantitative algorithm based on the renal corpuscle score (RC_S) and the tubulo-interstitial score (TI_S). The number of CD8+ T lymphocytes was higher than that of CD4+ T lymphocytes in each of the three areas and in each LN class, showing statistically significant differences. ANOVA analysis of all LN classes showed significant differences between periglomerular and interstitial CD4+ and CD8+ T lymphocytes, respectively. Irrespective of location, the number of CD8+ T lymphocytes statistically correlates with the RC_S and the TI_S; no significant correlations were found between the number of CD4+ T lymphocytes and the RC_S and the TI_S for all three considered areas. Our data provide strong evidence supporting the major role of CD8+ lymphocytes in LN lesion progression, with CD4+ lymphocytes playing a limited role.

In situ engineering of mRNA-CAR T cells using spleen-targeted ionizable lipid nanoparticles to eliminate cancer cells

Chimeric antigen receptor (CAR) T cell therapy has implemented impressive advances in the treatment of B-cell lymphoma. However, the complex production process of CAR T cells and hindrance of solid tumor penetration remain substantial challenges. Intriguingly, cell-targeting delivery of messenger RNA (mRNA) with ionizable lipid nanoparticles (mRNA-LNPs) is able to efficiently and precisely engineer T cells and other immune cells in vivo to perform their functions. Herein, we harnessed the ionizable LNPs to encapsulate mRNA encoding anti-tyrosinase related protein 1 (TRP1) CAR (CAR-LNPs) for in vivo generation of mRNA-CAR T cells to eliminate melanoma cells. Specifically, the anti-CD3 antibody (aCD3) armed mRNA-LNPs (CD3-mRNA-LNPs) selectively targeted T cells, resulting in the production of functional and therapeutic levels of CAR T cells both ex vivo and in vivo. These CD3-CAR-LNPs engineered CAR T cells were capable of infiltrating into the solid tumor and effectively eliminating melanoma cells with high TRP1 expression, significantly hindering tumor progression. Critically, CD3–7CAR-LNPs containing mRNA encoding both CAR and interleukin-7 (IL-7) generated 7CAR T cells that secreted IL-7, thereby enhancing the activity and proliferation of both CAR T cells and other intratumoral cytotoxic T cells. Alternatively, the employment of anti-programmed cell death protein 1 antibody (aPD-1) protected mRNA-CAR T cells from exhaustion, especially in combination with CD3–7CAR-LNPs, could significantly enhance the antitumor capability of CAR T cells without causing acute cytokine release syndrome (CRS).

449 (PB437): An IND-ready anti-CD4 monoclonal antibody in combination with PD-1 inhibitors for the treatment of solid tumors

449 (PB437): An IND-ready anti-CD4 monoclonal antibody in combination with PD-1 inhibitors for the treatment of solid tumors

Transient-resting culture after activation enhances the generation of CD8+ stem cell-like memory T cells from peripheral blood mononuclear cells

Adoptive cell therapy (ACT) has revolutionized the treatment of patients with cancer. The success of ACT depends largely on transferred T cell status, particularly their less-differentiated state with stem cell-like properties, which enhances ACT effectiveness. Stem cell-like memory T (TSCM) cells exhibit continuous self-renewal and multilineage differentiation similar to pluripotent stem cells. TSCM cells are promising candidates for cancer immunotherapies, whereas maintenance of a more stem-cell-like state before transfer is challenging. Here, we established a highly efficient protocol for generating CD8+ TSCM cells from peripheral blood mononuclear cells (PBMCs). The process involved activating PBMCs using anti-CD3 monoclonal antibody and RetroNectin, followed by a transient-resting culture period (24 h) and subsequent long-term expansion in vitro with interlukien-2. We report that this transient-resting culture after activation preserves CD8+ T cells in a stem memory phenotype (CD95+ CD45RA+ CCR7+) compared to the conventional culture method. Further, this approach reduces the expression of T cell immunoglobulin mucin-3, an exhaustion marker, and increases the expression of T cell factor-1, a master regulator of stemness even after long-term culture compared to the conventional culture method. In conclusion, our study presents a simplified and cost-effective method for generating and expanding CD8+ TSCM cells ex vivo. This approach streamlines the optimization of cancer immunotherapy using ACT.

Engineering potent chimeric antigen receptor T cells by programming signaling during T-cell activation

Programming cell signaling during T-cell activation represents a simple strategy for improving the potency of therapeutic T-cell products. Stim-R technology (Lyell Immunopharma) is a customizable, degradable synthetic cell biomimetic that emulates physiologic, cell-like presentation of signal molecules to control T-cell activation. A breadth of Stim-R formulations with different anti-CD3/anti-CD28 (αCD3/αCD28) antibody densities and stoichiometries were screened for their effects on multiple metrics of T-cell function. We identified an optimized formulation that produced receptor tyrosine kinase-like orphan receptor 1 (ROR1)-targeted chimeric antigen receptor (CAR) T cells with enhanced persistence and polyfunctionality in vitro, as assessed in repeat-stimulation assays, compared with a benchmark product generated using a conventional T-cell–activating reagent. In transcriptomic analyses, CAR T cells activated with Stim-R technology showed downregulation of exhaustion-associated gene sets and retained a unique subset of stem-like cells with effector-associated gene signatures following repeated exposure to tumor cells. Compared with the benchmark product, CAR T cells activated using the optimized Stim-R technology formulation exhibited higher peak expansion, prolonged persistence, and improved tumor control in a solid tumor xenograft model. Enhancing T-cell products with Stim-R technology during T-cell activation may help improve therapeutic efficacy against solid tumors.

Abstract AW12: Hyperinnervation and Immune-endocrine Interactions in Renal Arteriolar Hypertrophy during Inhibition of The Renin-Angiotensin System

Background: Chronic stimulation of renin cells by long-term use of renin-angiotensin system (RAS) inhibitors or renin deletion leads to concentric renal arteriolar hypertrophy frequently surrounded by immune-inflammatory cells. The disease is caused by the renin cells which increase in number and adopt an embryonic-secretory phenotype and induce the accumulation of smooth muscle cells that obstruct the vessels leading to ischemia. Normally, renin cells are innervated but it is unclear whether innervation of the renal arterial tree is affected under RAS inhibition. Hypothesis: Long-term RAS inhibition increases renal arteriolar innervation. Methods: We used two models of RAS inhibition: 1) Ren1 c-/- ; Ren1 c-Cre ; R26R mTmG mice studied at 3 months of age; 2) SMMHC CreERT2 ; R26R tdTomato ; Ren1 cYFP mice were treated with captopril for 6 months. We performed tissue clearing and 3D staining with an anti-tubulin β3 antibody. The expression of neurogenesis-related genes in renin lineage cells was examined using our previous single-cell RNA sequencing (scRNA-seq) data from mouse kidneys. We compared RNA expression of nerve growth factor (NGF) between Ren1 c−/− mice and control mice by qPCR and in situ hybridization (ISH). T cell infiltration was observed by immunostaining with anti-CD3 antibody. Results: 3-D imaging revealed that in both RAS inhibition models there was marked hyperinnervation. Renin cells expanded along and around the renal arterioles, and covered the glomeruli. Axons grew in numerous branches surrounding thickened afferent arterioles, bound tightly to renin cells and encasing the glomeruli. Our scRNA-seq data showed that Ngf , a gene important for neurogenesis and produced by immune cells, was highly expressed in renin cells. In Ren1 c−/− mice, expression of Ngf was significantly increased compared to controls (p=0.0054). ISH revealed that Ngf was highly expressed in Ren1 c−/− mice in the juxtaglomerular area and in the renal cortical stroma. Infiltration of T cells around affected arterioles was prominent in both models of RAS inhibition. Conclusion: Long-term inhibition of RAS leads to renal hyperinnervation, infiltration of immune cells and arteriolar hypertrophy. The identification of this neuro-immune-endocrine arterioles may help understand and treat vascular disease and hypertension.

Regulatory T cells protect against diabetic cardiomyopathy in db/db mice.

Regulatory T cells (Tregs) have protected against many cardiovascular diseases. This study was intended to explore the effect of Tregs on diabetic cardiomyopathy (DCM) using a db/db mouse model. Eight-week-old male db/db mice were randomly divided into four groups: the control group, administered 200 μL phosphate-buffered saline; the small-dose Treg group, administered 105 Tregs; the large-dose Treg group, administered 106 Tregs; and the PC group, administered 100 μg anti-CD25 specific antibody (PC61) and 106 Tregs. After 12 weeks, mice were euthanized. Transthoracic echocardiography was carried out at the beginning and end of the experiment. Relevant basic experiments to evaluate the effects of Tregs on DCM were carried out. Echocardiography showed that the impaired diastolic and systolic functions were significantly improved in mice administered large-dose Tregs. Large-dose Tregs significantly ameliorated myocardial hypertrophy and fibrosis, and decreased hypertrophic gene expression and collagen deposition. The protective effects of Tregs on diabetic hearts were associated with decreased oxidative stress, inflammatory response and apoptosis. In addition, Tregs promoted the activation of the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, whereas they inhibited extracellular signal-regulated kinase 1/2 and Jun N-terminal kinase phosphorylation, which might be responsible for the cardioprotective role of Tregs against DCM. Tregs ameliorated myocardial hypertrophy and fibrosis, improved cardiac dysfunction, and protected against DCM progression in db/db mice. The mechanisms involved a decrease of inflammatory response, oxidative stress and apoptosis, which might be mediated by phosphatidylinositol 3-kinase-protein kinase B and mitogen-activated protein kinase pathways. Hence, Tregs might serve as a promising therapeutic approach for DCM treatment.

Defining the immunological compatibility of graphene oxide-loaded PLGA scaffolds for biomedical applications

Graphene oxide (GO), a carbon-based nanomaterial, presents significant potential across biomedical fields such as bioimaging, drug delivery, biosensors, and phototherapy. This study examines the effects of integrating GO into poly(lactic-co-glycolic acid) (PLGA) scaffolds on human immune cell function. Our results demonstrate that high concentrations of GO reduce the viability of peripheral blood mononuclear cells (PBMCs) following stimulation with anti-CD3 antibody. This reduction extends to T lymphocyte activation, evident from the diminished proliferative response to T cell receptor engagement and impaired differentiation into T helper subsets and regulatory T cells. Interestingly, although GO induces a minimal response in resting monocytes, but it significantly affects both the viability and the differentiation potential of monocytes induced to mature toward M1 pro-inflammatory and M2-like immunoregulatory macrophages. This study seeks to address a critical gap by investigating the in vitro immunomodulatory effects of PLGA scaffolds incorporating various concentrations of GO on primary immune cells, specifically PBMCs isolated from healthy donors. Our findings emphasize the need to optimize the GO to PLGA ratios and scaffold design to advance PLGA-GO-based biomedical applications. Statement of significanceGraphene oxide (GO) holds immense promise for biomedical applications due to its unique properties. However, concerns regarding its potential to trigger adverse immune responses remain. This study addresses this critical gap by investigating the in vitro immunomodulatory effects of PLGA scaffolds incorporating increasing GO concentrations on human peripheral blood mononuclear cells (PBMCs). By elucidating the impact on cell viability, T cell proliferation and differentiation, and the maturation/polarization of antigen-presenting cells, this work offers valuable insights for designing safe and immunologically compatible GO-based biomaterials for future clinical translation.

Structure, function, and immunomodulation of the CD8 co-receptor.

Expressed on the surface of CD8+ T cells, the CD8 co-receptor is a key component of the T cells that contributes to antigen recognition, immune cell maturation, and immune cell signaling. While CD8 is widely recognized as a co-stimulatory molecule for conventional CD8+ αβ T cells, recent reports highlight its multifaceted role in both adaptive and innate immune responses. In this review, we discuss the utility of CD8 in relation to its immunomodulatory properties. We outline the unique structure and function of different CD8 domains (ectodomain, hinge, transmembrane, cytoplasmic tail) in the context of the distinct properties of CD8αα homodimers and CD8αβ heterodimers. We discuss CD8 features commonly used to construct chimeric antigen receptors for immunotherapy. We describe the molecular interactions of CD8 with classical MHC-I, non-classical MHCs, and Lck partners involved in T cell signaling. Engineered and naturally occurring CD8 mutations that alter immune responses are discussed. The applications of anti-CD8 monoclonal antibodies (mABs) that target CD8 are summarized. Finally, we examine the unique structure and function of several CD8/mAB complexes. Collectively, these findings reveal the promising immunomodulatory properties of CD8 and CD8 binding partners, not only to uncover basic immune system function, but to advance efforts towards translational research for targeted immunotherapy.

Hyperalgesic Effect Evoked by il-16 and its Participation in Inflammatory Hypernociception in Mice

The systemic administration of interleukin-16 (IL-16, 3–30 ng/kg) induced thermal hyperalgesia in mice, that was prevented by the acute injection of an anti-CD4 antibody (1 µg/kg), the depletion of circulating white blood cells by cyclophosphamide or the specific reduction of circulating CD4+ cells provoked by a high dose of an anti-CD4 antibody (30 µg/mouse, 24 h before). IL-16-induced hyperalgesia was locally inhibited after intraplantar (i.pl.) administration of the non-selective cyclooxygenase (COX) inhibitor diclofenac, the COX-1 inhibitor SC-560, the COX-2 inhibitor celecoxib, the TRPV1 antagonist capsazepine or the TRPA1 antagonist HC030031, thus demonstrating that prostaglandins and TRP channels are involved in this effect. The i.pl. administration of low doses of IL-16 (0.1–1 ng) evoked local hyperalgesia suggesting the possibility that IL-16 could participate in hypernociception associated to local tissue injury. Accordingly, IL-16 concentration measured by ELISA was increased in paws acutely inflamed with carrageenan or chronically inflamed with complete Freund´s adjuvant (CFA). This augmentation was reduced after white cell depletion with cyclophosphamide or neutrophil depletion with an anti-Ly6G antibody. Immunofluorescence and flow cytometry experiments showed that the increased concentration of IL-16 levels found in acutely inflamed paws is mainly related to the infiltration of IL-16+ neutrophils, although a reduced number of IL-16+ lymphocytes was also detected in paws inflamed with CFA. Supporting the functional role of IL-16 in inflammatory hypernociception, the administration of an anti-IL-16 antibody dose-dependently reduced carrageenan- and CFA-induced thermal hyperalgesia and mechanical allodynia. The interest of IL-16 as a target to counteract inflammatory pain is suggested.Graphical

Safety of teplizumab in patients with high-risk for diabetes mellitus type 1: A systematic review.

The incidence of diabetes mellitus type 1 (DM1) has been rising worldwide because of improvements in diagnostic techniques and improved access to care in countries with lower socioeconomic status. A new anti-CD4 antibody, Tep-lizumab, has been shown to delay the progression of DM1 and is the only medication approved for this indication. However, more information is needed about the safety profile of this drug. To identify the odds ratios (OR) of systems-based adverse effects for Teplizumab when compared to Placebo. An extensive systematic review was conducted from the inception of the medication until December 31, 2023. All clinical trials and studies that evaluated Teplizumab vs placebo were included in the initial review. The study protocol was designed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines guidelines and was registered in PROSPERO (ID: CRD42024496169). Crude OR were generated using RevMan Software version 5.4. After screening and review, 5 studies were selected to determine the risk of adverse effects of teplizumab compared to placebo. A total of 561 patients were included in the study population. Total adverse effects and system-based adverse effects were studied and reported. We determined that patients receiving Teplizumab had a higher risk of developing gastrointestinal (GI) (OR = 1.60, 95%CI: 1.01-2.52, P = 0.04), dermatological (OR = 6.33, 95%CI: 4.05-9.88, P < 0.00001) and hematological adverse effects (OR = 19.03, 95%CI: 11.09-32.66, P < 0.00001). These patients were also significantly likely to have active Epstein-Barr Virus infection (OR = 3.16, 95%CI: 1.51-6.64, P < 0.002). While our data showed that patients receiving Teplizumab did have a higher incidence of total adverse effects vs placebo, this finding did not reach statistical significance (OR = 2.25, 95%CI: 0.80-6.29, P = 0.12). Our systematic review suggests that Teplizumab patients are at risk for significant adverse effects, primarily related to GI, dermatological, and hematological systems. The total adverse effect data is limited as study populations are small. More studies should be conducted on this medication to better inform the target population of potential adverse effects.

The Pathogenesis of Type 1 Diabetes.

Type 1 diabetes (T1D) is a chronic autoimmune disease with a metabolic outcome. Studies over the past decades, have identified the contributions of genetics, environmental factors, and disorders of innate and adaptive immunity that collectively cause β-cell killing. The risk for T1D can be genetically identified but genotypes alone do not identify factors that lead to disease progression. The incidence of T1D has been increasing in the past few decades, which may be due to reduced exposure to infections and other environmental factors that can reduce autoimmunity (hygiene hypothesis). Once initiated, the disease pathogenesis progresses through stages that have been defined on the bases of immunologic (i.e., autoantibodies) and metabolic markers (glucose tolerance). The stages only loosely capture the risk for the time to diagnosis of disease, do not directly reflect disease activity, and there may be variance in the rate of progression within stages. In a general way, the stages can be used to identify patients at risk in whom interventions may be considered to modulate progression. This was achieved with the approval of teplizumab, a humanized anti-CD3 monoclonal antibody, for delaying the diagnosis of T1D.

19 Phase II Trial of Ubamatamab in MUC16-Expressing SMARCB1-Deficient Renal Medullary Carcinoma and Epithelioid Sarcoma

Abstract Background Mucin 16 (MUC16) is a large integral membrane glycoprotein that is highly expressed in malignancies such as ovarian cancer but only at low abundance in epithelial cells of normal tissues. Proteolytic cleavage of cell surface MUC16 results in the shedding of its extracellular portion, known as cancer antigen 125 (CA-125), into the bloodstream and a short, membrane-associated C-terminal MUC16 domain that remains on the cell surface. Renal medullary carcinoma (RMC) and epithelioid sarcoma (ES) are aggressive SMARCB1-deficient malignancies found to have elevated serum CA-125 levels in 70-80% of cases. Our preclinical studies suggest that upregulation of MUC16 upon SMARCB1 loss is a viable and attractive tumor target for SMARCB1-deficient malignancies such as ES and RMC. Ubamatamab is a human IgG4-based anti-MUC16 x anti-CD3 bispecific antibody that specifically targets the cell surface bound C-terminal MUC16 domain and can thus induce T cell–redirected killing of tumor cells even in the presence of high concentrations of CA-125. It would thus be a rationale therapy to use in SMARCB1-deficient malignancies expressing MUC16, including those such as RMC known to downregulate MHC Class I as a resistance mechanism to conventional immunotherapy. This is because CD3-targeting bispecific antibodies such as ubamatamab replace conventional signal 1 by engaging T cells regardless of MHC class I expression. As proof of concept, a 20-year-old patient with metastatic SMARCB1-negative ES expressing high levels of serum CA-125 achieved a durable (12+ months) partial response to ubamatamab after progressing on multiple prior therapies, including EZH2 inhibition with tazemetostat as well as anti-PD1/CTLA4 immune checkpoint inhibition with nivolumab plus ipilimumab. The patient reported Grade 2 CRS, pleural effusion, and pericardial effusion, all of which resolved without intervention1. This serves as proof-of-concept for the ability of CD3-targeted bispecifics to overcome resistance to immune checkpoint inhibition. Given this strong preclinical and clinical evidence, we have developed a phase II clinical trial of ubamatamab alone or in combination with the anti-PD1 immune-checkpoint inhibitor cemiplimab in patients with MUC16-expressing RMC and ES who have progressed on at least one line of prior therapy. Up to 20 patients will be enrolled from each disease cohort (ES and RMC) for a total of up to 40 patients. Patients enrolled in Stage I of the trial will receive ubamatamab monotherapy. Patients with disease progression on ubamatamab monotherapy during Stage I can proceed to stage II, which will evaluate the combination of ubamatamab with cemiplimab combination. The co-primary endpoints will be objective response rate (ORR) at any time during the trial and disease control rate (DCR) through 18 weeks. Secondary endpoints will include overall survival, progression-free survival, duration of response, and safety. All endpoints will be analyzed and reported separately for each disease cohort (RMC and ES), and for each Stage (ubamatamab monotherapy and combination ubamatamab with cemiplimab). The trial will utilize the time-to-event Bayesian Optimal Phase II (TOP) design, which maximizes statistical power with well-controlled type I errors. For patients with ES, the joint null hypotheses are that the objective response rate (ORR) is 15% and the disease control rate (DCR) is 26%. The regimen will be promising if either ORR is greater than 15% or DCR is greater than 26% with 69.6% power to declare this an interesting regimen if ORR is 30% and the DCR is 43%. For patients with RMC, the joint null hypotheses are that the objective response rate (ORR) is 15% and the disease control rate (DCR) is 15%. The regimen will be promising if either ORR is greater than 15% or DCR is greater than 15% with 71.4% power to declare this an interesting regimen if ORR is 30% and the DCR is 30%. Pre- and post-treatment correlative analyses will be performed in blood and tumor biopsy tissues to identify changes in specific immune cell subsets and elucidate the dynamic evolution of tumor and immune cell compartments as well as their spatial relationships following ubamatamab alone or in combination with cemiplimab. References 1 Revon-Riviere G, Chami R, Mills D, et al. Mucin 16 (cancer antigen 125) Expression in Epithelioid Sarcoma leads to Single-Patient Study with Bispecific T-Cell Engager Ubamatamab (Mucin16xCD3): A Bench-To-Bedside Experience. Connective Tissue Oncology Society, Nov 16–19, 2022, Vancouver, Canada.

Development of anex vivo patient-derived tumor model (PDTM) to assess the tumor microenvironment in renal cell carcinoma (RCC)

Abstract Background With the rise of immune checkpoint inhibitors (ICIs) as the primary treatment option for metastatic RCC, investigating the role of T cells within the tumor microenvironment (TME) is a critical component of understanding both treatment response and resistance. Prior efforts, including single-cell transcriptomic approaches, have provided an important landscape of T cell transcriptional phenotypes. However, these immuno-profiling efforts require validation through functional interrogation of the TME to facilitate the development of novel immunomodulatory therapies. Thus, we established a patient derived tumor model (PDTM) system to directly assess the effect of inhibitory immune interactions on T cell function and anti-tumor activity in the RCC TME. In this initial proof-of-concept study, we evaluated T cell activation in the RCC TME using the PDTM system. Methods Fresh tumor samples were obtained from surgical resections of RCC at Yale-New Haven Hospital. The tumor was minced to ~1-3 mm³ pieces and suspended in an air-liquid interface system, consisting of tumor fragments embedded in a collagen matrix on an insert with a semi-permeable membrane, exposed to culture media. The tumor fragment and matrix suspension were carefully pipetted onto the Millicell insert, which served as the top layer. The PDTM setup includes an inner dish containing the bottom gel layer and the tissue-containing top layer. To complete the assembly, 1.5 ml of DMEM media with or without an anti-CD3 monoclonal antibody (aCD3mAb) and 500 nM of anti-PD-1 monoclonal antibody (aPD1mAb) was added to the outer dish surrounding the insert. Results We successfully optimized PDTM experimental workflows for culture, dissociation, and analysis using immunohistochemistry (IHC), flow cytometry (FCM), and enzyme-linked immunosorbent assays (ELISA). Hematoxylin and eosin (H&amp;E) staining and IHC showed that the TME cellular architecture and immune cell composition was broadly preserved during the three day experimental period. Using FCM to analyze the dissociated tumor samples, we identified well-preserved CA9+ tumor cells, CD4+ and CD8+ T cell populations, CD4+CD25+ regulatory T cells, CD56+ natural killer cells, CD20+ B cells, and CD14+CD11b+ myeloid subsets including monocytes and CD163-/+macrophages. Among the T cells, we detected PD1+, LAG3+, TIM3+, and TIGIT+ cells. For dose-response analysis of aCD3mAb, we observed that stimulation with 0.025 ng/mL aCD3mAb for T cells from healthy donor peripheral blood mononuclear cells (PBMCs) yielded significant but non-saturating levels of interferon gamma (IFN-γ) production as quantified by ELISA. We tested the effect of the anti-PD-1 antibody on PDTM under the low-dose of aCD3mAb, and importantly, found that treatment of the PDTM with aPD1mAb resulted in more activated CD8 T cells and higher IFN-γ production than the control samples. Conclusions Through optimization of assays evaluating T cell cytokine production, we were able to assess multiple axes of T-cell function in the RCC TME. This study revealed that our PDTM system preserves the RCC TME for functional interrogation. Furthermore, our system for assessing T cell phenotype and cytokine production successfully demonstrated the activity of PD-1 blockade ex vivo. Taken together, this novel ex vivo PDTM system has extensive applications in the study of RCC, including assessing the impact of ICIs on T cell function. DOD CDMRP Funding: yes

Early graft-infiltrating lymphocytes are not associated with graft rejection in a mouse model of skin transplantation.

Graft-infiltrating lymphocytes (GILs) play an important role in promoting rejection after organ transplantation. We recently reported that GILs that accumulated up to 3 days post-transplantation did not promote rejection, whereas GILs present 3-5 days post-transplantation promoted rejection in a mouse heart transplantation model. However, the immunological behaviour of GILs in murine skin transplantation remains unclear. GILs were isolated on days 3, 5 or 7 post-transplantation from C57BL/6 (B6) allogeneic skin grafts transplanted onto BALB/c mice. BALB/c Rag2-/- γc-/- mice (BRGs) underwent B6 skin graft transplantation 10 weeks after adoptive transfer of day 3, 5, or 7 GILs. BRGs reconstituted with day 5 or 7 GILs completely rejected B6 grafts. However, when B6 grafts harvested from recipient BALB/c mice on day 5 or 7 were re-transplanted into BRGs, half of the re-transplanted day 5 grafts established long-term survival, although all re-transplanted day 7 grafts were rejected. BRGs reconstituted with day 3 GILs did not reject B6 grafts. Consistently, re-transplantation using day 3 skin grafts resulted in no rejection. Administration of anti-CD25 antibodies did not prevent the phenomenon observed for the day 3 skin grafts. Furthermore, BRGs reconstituted with splenocytes from naïve BALB/c mice immediately rejected the naïve B6 skin grafts and the re-transplanted day 3 B6 grafts, suggesting that day 3 GILs were unable to induce allograft rejection during the rejection process. In conclusion, the immunological role of GILs depends on the time since transplantation. Day 3 GILs had neither protective nor alloreactive effects in the skin transplant model.