Differentiated Effector Memory Research Articles

Prognostic implications of a CD8+ TEMRA to CD4+Treg imbalance in mandibular fracture healing: a prospective analysis of immune profiles

IntroductionOpen reduction and fixation are the standard of care for treating mandibular fractures and usually lead to successful healing. However, complications such as delayed healing, non-union, and infection can compromise patient outcomes and increase healthcare costs. The initial inflammatory response, particularly the response involving specific CD8+ T cell subpopulations, is thought to play a critical role in healing long bone fractures. In this study, we investigated the role of these immune cell profiles in patients with impaired healing of mandibular fractures.Materials and methodsIn this prospective study, we included patients with mandibular fractures surgically treated at Charité – Universitätsmedizin Berlin, Germany, between September 2020 and December 2022. We used follow-up imaging and clinical assessment to evaluate bone healing. In addition, we analyzed immune cell profiles using flow cytometry and quantified cytokine levels using electrochemiluminescence-based multiplex immunoassays in preoperative blood samples.ResultsOut of the 55 patients enrolled, 38 met the inclusion criteria (30 men and 8 women; mean age 32.18 years). Radiographic evaluation revealed 31 cases of normal healing and 7 cases of incomplete consolidation, including 1 case of non-union. Patients with impaired healing exhibited increased levels of terminally differentiated effector memory CD8+ T cells (TEMRA) and a higher TEMRA to regulatory T cell (Treg) ratio, compared with those with normal healing.ConclusionsOur analysis of mandibular fracture cases confirms our initial hypothesis derived from long bone fracture healing: monitoring the TEMRA to Treg ratio in preoperative blood can be an early indicator of patients at risk of impaired bone healing. Radiologic follow-up enabled us to detect healing complications that might not be detected by clinical assessment only. This study highlights the potential of individual immune profiles to predict successful healing and may form the basis for future strategies to manage healing complications.

Anti-CD19 CAR-T cells are effective in severe idiopathic Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoantibody-mediated disease of the neuromuscular junction characterized by muscular weakness. Autoantibodies to presynaptic P/Q-type voltage-gated calcium channels (VGCCs) induce defective neuromuscular function. In severe cases, current immunosuppressive and immunomodulatory treatment strategies are often insufficient. First reports show beneficial effects of anti-CD19 chimeric antigen receptor (CAR)-T cell therapy in patients with autoantibody-mediated myasthenia gravis. We report a patient with isolated idiopathic LEMS treated with autologous anti-CD19-CAR-T cells. In this patient, CAR-T infusion leads to expansion of predominantly CD4+ CAR-T cells with a terminally differentiated effector memory cells re-expressing CD45RA (TEMRA)-like phenotype indicating cytotoxic capabilities and subsequent B cell depletion. VGCC antibody titers decrease, resulting in a clinical improvement of LEMS symptoms, e.g., 8-fold increase in walking distance. The patient does not show relevant side effects except for cytokine release syndrome grade 2 and intermittent neutropenia suggesting that anti-CD19 CAR-T cell therapy may be a treatment option in patients with LEMS.

Rapamycin Prevents Expansion of Costimulation Blockade-resistant CD8+ Alloreactive Memory Cells following Depletional Induction in Renal Transplant Recipients.

Alemtuzumab induction with belatacept/rapamycin-based maintenance immunotherapy (ABR) prevents kidney allograft rejection and specifically limits early costimulation blockade-resistant rejection (CoBRR). To evaluate the mechanisms by which this regimen alters CoBRR, we characterized the phenotype and functional response of preexisting memory cells to allogeneic endothelial cells using intracellular cytokine staining and flow cytometry. IL-7-induced lymphocyte proliferation in the presence or absence of rapamycin was assessed to characterize the phenotype of proliferating cells. Lymphocytes from 40 recipients who underwent transplant using the ABR regimen were studied longitudinally. The rapid immunoresponses of preexisting alloreactive cells to allogeneic endothelial cells were predominantly CD8+TNF-α+/IFN-γ+ cells. These cells were effector memory (TEM) and terminally differentiated effector memory cells lacking CD28 expression, and most were CD57+PD1-. Neither rapamycin nor belatacept directly inhibited these cells. IL-7, a cytokine induced during lymphopenia postdepletion, provoked dramatic CD8+ TEM cell proliferation and a low level of CD8+CD57+PD1- cell expansion invitro. The IL-7 stimulation induced CD8+ cell mTOR phosphorylation, and rapamycin treatment markedly inhibited IL-7-induced TEM and CD57+PD1- cell expansion. This effect was evident in patients receiving the ABR in that the repopulation of CD8+CD57+PD1- TEM cells was substantially suppressed for at least 36 mo after transplant. These findings help define one mechanism by which a costimulation blockade/rapamycin-based therapy following alemtuzumab induction minimizes CoBRR, namely that in the presence of rapamycin, costimulation-resistant alloreactive cells are disproportionately ineffective at repopulating following post-transplant T cell depletion.

MRNA-1273 vaccination induces polyfunctional memory CD4 and CD8 T cell responses in patients with solid cancers undergoing immunotherapy or/and chemotherapy.

Research has confirmed the safety and comparable seroconversion rates following SARS-CoV-2 vaccination in patients with solid cancers. However, the impact of cancer treatment on vaccine-induced T cell responses remains poorly understood. In this study, we expand on previous findings within the VOICE trial by evaluating the functional and phenotypic composition of mRNA-1273-induced T cell responses in patients with solid tumors undergoing immunotherapy, chemotherapy, or both, compared to individuals without cancer. We conducted an ELISpot analysis on 386 participants to assess spike-specific T cell responses 28 days after full vaccination. Further in-depth characterization of using flow cytometry was performed on a subset of 63 participants to analyze the functional phenotype and differentiation state of spike-specific T cell responses. ELISpot analysis showed robust induction of spike-specific T cell responses across all treatment groups, with response rates ranging from 75% to 80%. Flow cytometry analysis revealed a distinctive cytokine production pattern across cohorts, with CD4 T cells producing IFNγ, TNF, and IL-2, and CD8 T cells producing IFNγ, TNF, and CCL4. Variations were observed in the proportion of monofunctional CD4 T cells producing TNF, particularly higher in individuals without cancer and patients treated with chemotherapy alone, while those treated with immunotherapy or chemoimmunotherapy predominantly produced IFNγ. Despite these differences, polyfunctional spike-specific memory CD4 and CD8 T cell responses were comparable across cohorts. Notably, immunotherapy-treated patients exhibited an expansion of spike-specific CD4 T cells with a terminally differentiated effector memory phenotype. These findings demonstrate that systemic treatment in patients with solid tumors does not compromise the quality of polyfunctional mRNA-1273-induced T cell responses. This underscores the importance of COVID-19 vaccination in patients with solid cancers undergoing systemic treatment.

Low-level HIV-1 viremia affects T-cell activation and senescence in long-term treated adults in the INSTI era

BackgroundAround 10% of people with HIV (PWH) exhibit a low-level viremia (LLV) under antiretroviral therapy (ART). However, its origin and clinical significance are largely unknown, particularly at viremias between 50 and 200 copies/mL and under modern ART based on integrase strand transfer inhibitors (INSTIs). Our aim was to characterize their poor immune response against HIV in comparison to individuals with suppressed viremia (SV) and non-HIV controls (NHC).MethodsTransversal observational study in 81 matched participants: 27 PWH with LLV, 27 PWH with SV, and 27 NHC. Activation (CD25, HLA-DR, and CD38) and senescence [CD57, PD1, and HAVCR2 (TIM3)] were characterized in peripheral T-cell subsets by spectral flow cytometry. 45 soluble biomarkers of systemic inflammation were evaluated by immunoassays. Differences in cell frequencies and plasma biomarkers among groups were evaluated by a generalized additive model for location, scale, and shape (GAMLSS) and generalized linear model (GLM) respectively, adjusted by age, sex at birth, and ART regimen.ResultsThe median age was 53 years and 77.8% were male. Compared to NHC, PWH showed a lower CD4+/CD8+ ratio and increased activation, senescence, and inflammation, highlighting IL-13 in LLV. In addition, LLV showed a downtrend in the frequency of CD8+ naive and effector memory (EM) type 1 compared to SV, along with higher activation and senescence in CD4+ and CD8+ EM and terminally differentiated effector memory RA+ (TEMRA) subpopulations. No significant differences in systemic inflammation were observed between PWH groups.ConclusionLLV between 50 and 200 copies/mL leads to reduced cytotoxic activity and T-cell dysfunction that could affect cytokine production, being unable to control and eliminate infected cells. The increase in senescence markers suggests a progressive loss of immunological memory and a reduction in the proliferative capacity of immune cells. This accelerated immune aging could lead to an increased risk of developing future comorbidities. These findings strongly advocate for heightened surveillance of these PWH to promptly identify potential future complications.

Circulating CD8 + LGALS9 + T Cell Population Exhibiting Low Cytotoxic Characteristics are Decreased in Patients with Systemic Lupus Erythematosus.

LGALS9, also known as Galectin-9 and a member of the β-galactosidase family, plays a crucial role in immune regulation. However, its expression and function in CD8 T cells, as well as its association with cytotoxic T lymphocytes (CTL), remain unclear. This study aims to investigate LGALS9 expression patterns in human circulating CD8 T lymphocytes and elucidate its clinical significance in Systemic Lupus Erythematosus (SLE). Blood samples from 56 healthy controls and 50 new-onset SLE patients were collected. Flow cytometry was utilized to analyze LGALS9 expression in circulating CD8 T lymphocytes via intracellular staining. Compared to LGALS9 + CD8 + T cells, LGALS9-CD8 + T cells showed increased secretion of Granzyme B (GZMB) and Perforin, along with elevated expression levels of GPR56, CX3CR1, KLRD1, KLRF1, PD1, and CD29. A higher proportion of Tn (naive T cells) and TCM (central memory T cells) showed LGALS9 positivity, compared to TEM (effector memory T cells) and TEMRA (terminally differentiated effector memory T cells re-expressing CD45RA). Clinically, the downregulation of LGALS9 expression was significant in SLE patients. LGALS9 + CD8 + T cells exhibited an Area Under the Curve (AUC) of 0.6916, while CX3CR1 + in LGALS9 + CD8 + T cells had an AUC of 0.6478, and KLRF1 + had an AUC of 0.6419, for distinguishing SLE from healthy individuals. In conclusion, CD8 + LGALS9 + T cells display characteristics of low cytotoxicity, and their reduction is evident in SLE patients, potentially implicating them in SLE pathogenesis and providing diagnostic assistance.

Immunological characteristics of a recombinant alphaherpesvirus with an envelope-embedded Cap protein of circovirus.

Variant pseudorabies virus (PRV) is a newly emerged zoonotic pathogen that can cause human blindness. PRV can take advantage of its large genome and multiple non-essential genes to construct recombinant attenuated vaccines carrying foreign genes. However, a major problem is that the foreign genes in recombinant PRV are only integrated into the genome for independent expression, rather than assembled on the surface of virion. We reported a recombinant PRV with deleted gE/TK genes and an inserted porcine circovirus virus 2 (PCV2) Cap gene into the extracellular domain of the PRV gE gene using the Cre-loxP recombinant system combined with the CRISPR-Cas9 gene editing system. This recombinant PRV (PRV-Cap), with the envelope-embedded Cap protein, exhibits a similar replication ability to its parental virus. An immunogenicity assay revealed that PRV-Cap immunized mice have 100% resistance to lethal PRV and PCV2 attacks. Neutralization antibody and ELISPOT detections indicated that PRV-Cap can enhance neutralizing antibodies to PRV and produce IFN-γ secreting T cells specific for both PRV and PCV2. Immunological mechanistic investigation revealed that initial immunization with PRV-Cap stimulates significantly early activation and expansion of CD69+ T cells, promoting the activation of CD4 Tfh cell dependent germinal B cells and producing effectively specific effector memory T and B cells. Booster immunization with PRV-Cap recalled the activation of PRV-specific IFN-γ+IL-2+CD4+ T cells and IFN-γ+TNF-α+CD8+ T cells, as well as PCV2-specific IFN-γ+TNF-α+CD8+ T cells. Collectively, our data suggested an immunological mechanism in that the recombinant PRV with envelope-assembled PCV2 Cap protein can serve as an excellent vaccine candidate for combined immunity against PRV and PCV2, and provided a cost-effective method for the production of PRV- PCV2 vaccine.

Memory inflation: Beyond the acute phase of viral infection.

Memory inflation is confirmed as the most commonly dysregulation of host immunity with antigen-independent manner in mammals after viral infection. By generating large numbers of effector/memory and terminal differentiated effector memory CD8+ T cells with diminished naïve subsets, memory inflation is believed to play critical roles in connecting the viral infection and the onset of multiple diseases. Here, we reviewed the current understanding of memory inflated CD8+ T cells in their distinct phenotypic features that different from exhausted subsets; the intrinsic and extrinsic roles in regulating the formation of memory inflation; and the key proteins in maintaining the expansion and proliferation of inflationary populations. More importantly, based on the evidences from both clinic and animal models, we summarized the potential mechanisms of memory inflation to trigger autoimmune neuropathies, such as Guillain-Barré syndrome and multiple sclerosis; the correlations of memory inflation between tumorigenesis and resistance of tumour immunotherapies; as well as the effects of memory inflation to facilitate vascular disease progression. To sum up, better understanding of memory inflation could provide us an opportunity to beyond the acute phase of viral infection, and shed a light on the long-term influences of CD8+ T cell heterogeneity in dampen host immune homeostasis.

The embodiment of the neighborhood socioeconomic environment in the architecture of the immune system.

There is growing recognition of the importance of immune health for understanding the origins of ageing-related disease and decline. Numerous studies have demonstrated consistent associations between the social determinants of health and immunosenescence (i.e. ageing of the immune system). Yet few studies have interrogated the relationship between neighborhood socioeconomic status (nSES) and biologically specific measures of immunosenescence. We used data from the US Health and Retirement Study to measure immunosenescence linked with neighborhood socioeconomic data from the National Neighborhood Data Archive to examine associations between indicators of nSES and immunosenescence. We found associations between both the ratio of terminally differentiated effector memory to naïve (EMRA:Naïve) CD4+ T cells and cytomegalovirus (CMV) immunoglobulin G (IgG) levels and nSES. For the CD4+ EMRA:Naïve ratio, each 1% increase in the neighborhood disadvantage index was associated with a 0.005 standard deviation higher value of the EMRA:Naïve ratio (95% CI: 0.0003, 0.01) indicating that living in a neighborhood that is 10% higher in disadvantage is associated with a 0.05 higher standardized value of the CD4+ EMRA:Naïve ratio. The results were fully attenuated when adjusting for both individual-level SES and race/ethnicity. For CMV IgG antibodies, a 1% increase in neighborhood disadvantage was associated a 0.03 standard deviation higher value of CMV IgG antibodies (β = 0.03; 95% CI: 0.002, 0.03) indicating that living in a neighborhood that is 10% higher in disadvantage is associated with a 0.3 higher standardized value of CMV. This association was attenuated though still statistically significant when controlling for individual-level SES and race/ethnicity. The findings from this study provide compelling initial evidence that large, nonspecific social exposures, such as neighborhood socioeconomic conditions, can become embodied in cellular processes of immune ageing.

Terminally differentiated effector memory T cells associate with cognitive and AD-related biomarkers in an aging-based community cohort

Background and purposeThe immune response changes during aging and the progression of Alzheimer’s disease (AD) and related dementia (ADRD). Terminally differentiated effector memory T cells (called TEMRA) are important during aging and AD due to their cytotoxic phenotype and association with cognitive decline. However, it is not clear if the changes seen in TEMRAs are specific to AD-related cognitive decline specifically or are more generally correlated with cognitive decline. This study aimed to examine whether TEMRAs are associated with cognition and plasma biomarkers of AD, neurodegeneration, and neuroinflammation in a community-based cohort of older adults.MethodsStudy participants from a University of Kentucky Alzheimer’s Disease Research Center (UK-ADRC) community-based cohort of aging and dementia were used to test our hypothesis. There were 84 participants, 44 women and 40 men. Participants underwent physical examination, neurological examination, medical history, cognitive testing, and blood collection to determine plasma biomarker levels (Aβ42/Aβ40 ratio, total tau, Neurofilament Light chain (Nf-L), Glial Fibrillary Acidic Protein (GFAP)) and to isolate peripheral blood mononuclear cells (PBMCs). Flow cytometry was used to analyze PBMCs from study participants for effector and memory T cell populations, including CD4+ and CD8+ central memory T cells (TCM), Naïve T cells, effector memory T cells (TEM), and effector memory CD45RA+ T cells (TEMRA) immune cell markers.ResultsCD8+ TEMRAs were positively correlated with Nf-L and GFAP. We found no significant difference in CD8+ TEMRAs based on cognitive scores and no associations between CD8+ TEMRAs and AD-related biomarkers. CD4+ TEMRAs were associated with cognitive impairment on the MMSE. Gender was not associated with TEMRAs, but it did show an association with other T cell populations.ConclusionThese findings suggest that the accumulation of CD8+ TEMRAs may be a response to neuronal injury (Nf-L) and neuroinflammation (GFAP) during aging or the progression of AD and ADRD. As our findings in a community-based cohort were not clinically-defined AD participants but included all ADRDs, this suggests that TEMRAs may be associated with changes in systemic immune T cell subsets associated with the onset of pathology.

Identification of potential immune-related mechanisms related to the development of multiple myeloma.

Although significant advances have been made in the treatment of multiple myeloma (MM), leading to unprecedented response and survival rates among patients, the majority eventually relapse, and a cure remains elusive. This situation is closely related to an incomplete understanding of the immune microenvironment, especially monocytes/macrophages in patients with treatment-naïve MM. The aim of this study was to provide insight into the immune microenvironment, especially monocytes/macrophages, in patients with treatment-naïve MM. This study used the single-cell RNA sequencing (scRNA-seq) data of both patients with MM and heathy donors to identify immune cells, including natural killer (NK) cells, T cells, dendritic cells (DCs), and monocytes/macrophages. Transcriptomic data and flow cytometry analysis of monocytes/macrophages were used to further examine the effect of monocytes/macrophages in treatment-naïve MM patients. A significant difference was observed between the bone marrow (BM) immune cells of the healthy controls and treatment-naïve MM patients through scRNA-seq. It is noteworthy that, through an scRNA-seq data analysis, this study found that interferon (IFN)-induced NK/T cells, terminally differentiated effector memory (TEMRA) cells, T-helper cells characterized by expression of IFN-stimulated genes (ISG + Th cells), IFN-responding exhausted T cells, mannose receptor C-type 1 (MRC1) + DCs, IFN-responding DCs, MHCII + DCs, and immunosuppressive monocytes/macrophages were enriched in patients with treatment-naïve MM. Significantly, transcriptomic data of monocytes/macrophages demonstrated that "don't eat me"-related genes and IFN-induced genes increase in treatment-naïve MM patients. Furthermore, scRNA-seq, transcriptomic data, and flow cytometry also showed an increased proportion of CD16 + monocytes/macrophages and expression level of CD16. Cell-cell communication analysis indicated that monocytes/macrophages, whose related important signaling pathways include migration inhibitory factor (MIF) and interleukin 16 (IL-16) signaling pathway, are key players in treatment-naïve MM patients. Our findings provide a comprehensive and in-depth molecular characterization of BM immune cell census in MM patients, especially for monocytes/macrophages. Targeting macrophages may be a novel treatment strategy for patients with MM.

Memory CD8 T cells are vulnerable to chronic IFN-γ signals but not to CD4 T cell deficiency in MHCII-deficient mice

The mechanisms by which the number of memory CD8 T cells is stably maintained remains incompletely understood. It has been postulated that maintaining them requires help from CD4 T cells, because adoptively transferred memory CD8 T cells persist poorly in MHC class II (MHCII)-deficient mice. Here we show that chronic interferon-γ signals, not CD4 T cell-deficiency, are responsible for their attrition in MHCII-deficient environments. Excess IFN-γ is produced primarily by endogenous colonic CD8 T cells in MHCII-deficient mice. IFN-γ neutralization restores the number of memory CD8 T cells in MHCII-deficient mice, whereas repeated IFN-γ administration or transduction of a gain-of-function STAT1 mutant reduces their number in wild-type mice. CD127high memory cells proliferate actively in response to IFN-γ signals, but are more susceptible to attrition than CD127low terminally differentiated effector memory cells. Furthermore, single-cell RNA-sequencing of memory CD8 T cells reveals proliferating cells that resemble short-lived, terminal effector cells and documents global downregulation of gene signatures of long-lived memory cells in MHCII-deficient environments. We propose that chronic IFN-γ signals deplete memory CD8 T cells by compromising their long-term survival and by diverting self-renewing CD127high cells toward terminal differentiation.

Abstract PR003: T cell receptor repertoire and diversity are prognostic markers in bladder cancer

Abstract T cells represent essential effector cells in the intrinsic antitumor immune response. Cancer-specific T cells can recognize cancer neoantigens through their T cell receptors (TCRs). The expansion of these clones is believed to be an early response to malignancy. We hypothesized that the T cell landscape offers insights into immune competency. We aimed to characterize the TCR repertoire in patients with bladder cancer and explore correlations with disease outcomes. We analyzed the TCR landscape in a cohort of 119 patients with muscle-invasive bladder cancer (MIBC) treated with chemotherapy followed by radical cystectomy. Peripheral and tumor TCR repertoires were produced using ultradeep amplicon-based sequencing of the TCR beta chain. T cell fractions were inferred from whole exome sequencing data of blood DNA using TcellExTRECT. Latent viral DNA was investigated in plasma whole genome sequencing data using Kraken2. Antigen targets were estimated using GLIPH2. The T cell subtype compositions in tumor and blood were investigated in four patients with bladder cancer using the Chromium Single Cell Immune profiling kit from 10X Genomics. Low pre-treatment peripheral TCR diversity was associated with worse overall survival (HR = 2.3, p = 0.024, n = 119) in patients with MIBC, particularly when combined with a low fraction of circulating T cells (HR= 4.7, p = 0.00049, n = 67). We validated these findings in two independent cohorts of patients with MIBC (p = 0.01, n = 107; p = 0.042, n = 79). The low-diversity TCR repertoires were characterized by large expanded T cell clones that persisted over time. Longitudinal analysis indicated a potential adverse impact of treatment, evidenced by a reduction in TCR diversity and circulating T cells over time in patients with initially high-diversity repertoires. TCR target annotation revealed that expanded T cell clones disproportionately targeted latent viral infections and cytomegalovirus DNA detection was strongly associated with low TCR diversity (p = 5.3 × 10−5). We observed a notable disparity between tumor and peripheral blood TCR repertoires. Single-cell sequencing revealed that regulatory T cells were prevalent in the tumor, whereas a combination of cytotoxic and naïve T cells dominated the blood. More explicitly, expanded clones in the blood were commonly annotated as terminally differentiated effector memory T cells expressing high levels of cytotoxic and exhausted genes. Our results suggest that high peripheral TCR diversity and high T cell fraction are markers of general immune competence, reflecting the ability to eradicate cancer and other diseases. In contrast, the expanded persistent clones predominating the low peripheral TCR diversity repertoires are likely exhausted and less likely to exhibit tumor specificity or effective disease-fighting capabilities. Our findings underline the crucial role of the immune system in determining disease outcomes and highlight the potential for improving immune health as a promising approach for future treatment and prevention. Citation Format: Nanna Kristjánsdóttir, Asbjørn Kjær, Iver Nordentoft, Randi I Juul, Karin Birkenkamp-Demtröder, Johanne Ahrenfeldt, Trine Strandgaard, Deema Radif, Darren Hodgson, Christopher Abbosh, Hugo JWL Aerts, Mads Agerbæk, Jørgen B Jensen, Nicolai J. Birkbak, Lars Dyrskjøt. T cell receptor repertoire and diversity are prognostic markers in bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr PR003.

Construction of CD138-targeted chimeric antigen receptor- modified T cells and their effect in multiple myeloma therapy

Objective: To construct a novel chimeric antigen receptor T (CAR-T) cell targeting CD138 and to investigate its cytotoxicity against myeloma cells. Methods: The hybridoma strain that can stably secrete the CD138 monoclonal antibody (mAb) was prepared and obtained through monoclonal antibody screening technology. The hybridoma strain cells were intraperitoneally injected into mice to produce ascites containing monoclonal antibodies, which were then collected and purified to obtain pure CD138 mAb. Further examinations were performed to assess the biological characteristics of CD138 mAb. The variable region sequence of this antibody was amplified through reverse transcription polymerase chain reaction and was used as the antigen recognition domain of CD138 CAR, which was subsequently expressed on the surface of T cells by lentiviral infection. Flow cytometry was employed to assess the phenotype of CD138 CAR-T cells. In vitro cytotoxicity and degranulation assays were performed to evaluate their antitumor effects. Results: ① We successfully prepared anti-human CD138 antibody hybridoma cell lines and screened a hybridoma cell strain, 5G2, which could persistently and stably secrete the anti-CD138 antibody. ② The purified CD138 (5G2) mAb can especially recognize CD138(+) cells with a binding affinity constant (K(D)) of 6.011×10(-9) mol/L and showed no significant binding activity with CD138(-) cells. ③The variable region sequence of the CD138 (5G2) antibody was obtained using molecular cloning technology, and CD138 (5G2) CAR was successfully constructed and expressed on T cells through lentivirus infection and, concurrently, demonstrated effective binding to recombinant human CD138 protein.④ The proliferation of T cells transduced with the CD138 (5G2) CAR was highly efficient. The phenotype analysis revealed that CD138 (5G2) CAR-T cells exhibited a greater tendency to differentiate into central memory T cells and memory stem T cells, with a reduced proportion of terminally differentiated effector memory subsets. ⑤CD138 (5G2) CAR-T cells demonstrated specific cytotoxicity against CD138(+) myeloma cell line H929, whereas CD138(-) cell line K562 remained unaffected. The percentage of residual H929 cells was (12.92±8.02) % after co-culturing with CD138 (5G2) CAR-T cells, while (54.25±15.79) % was left in the Vector-T group (E∶T=1∶2; P<0.001). ⑥Results of degranulation assays demonstrated a significant activation of CD138 (5G2) CAR-T cells after co-culture with the H929 cell line, whereas no significant activation was observed in Vector-T cells [ (25.78±3.35) % vs (6.13±1.30) %, P<0.001]. ⑦After co-culturing with CD138(+) cells, CD138 (5G2) CAR-T cells exhibited a significant increase in cytokine secretion compared to the Vector-T group [interleukin-2: (1 697.52±599.05) pg/ml vs (5.07±1.17) pg/ml, P<0.001; interferon-γ: (3 312.20±486.38) pg/ml vs (9.28±1.46) pg/ml, P<0.001; and tumor necrosis factor-α: (1 837.43±640.49) pg/ml vs (8.75±1.65) pg/ml, P<0.001]. However, no significant difference was observed in cytokine secretion levels between the two groups after co-culturing with CD138(-) cells. Conclusion: This study successfully prepared a novel monoclonal antibody against CD138, and CAR-T cells constructed with the antigen recognition domain derived from this 5G2 mAb demonstrated effective antitumor activity against myeloma cells. This can be used as a new option for the detection of the CD138 antigen and proposes a novel strategy for multiple myeloma immunotherapy.

Abstract PO5-24-12: IRX5010, a Highly Selective RARγ Nuclear Receptor Agonist Compound Inhibits In Vivo Growth of Murine EMT-6 Triple Negative Breast Cancer and Human JIMT-1Her2+ Breast Cancer By Induction of Tumor-Infiltrating Effector Memory T-cells

Abstract Research Objectives and Rationale: Previously, RARγ agonism has been shown to play an essential role in CD8 T-cell-mediated immunity to infectious pathogens. However, we found no previous reports on effects of RARγ agonists on in vivo tumor growth of triple negative or Her2+ breast cancers. Here we explored whether RARγ could play a critical role in T-cell-mediated immunity in these breast cancers, using potent highly selective novel RARγ agonist compounds. Experimental methods and results: We synthesized and screened compounds for selective transactivation of RAR γ in reporter assays. Three highly potent compounds, demonstrating highly selective RARγ transactivation at less than one nanomolar concentrations, were selected for further evaluation of potential anti-cancer activities in vitro. None of the three evaluated compounds demonstrated significant inhibitory effects on in vitro growth of EMT-6 triple negative breast cancer cells at concentrations of 20-100 millimolar, indicating that the three compounds have insignificant direct inhibitory effects on EMT-6 cancer cell growth in vitro. We then examined the effects of one of the compounds in vivo in a syngeneic mouse model of EMT-6 triple negative breast cancer. Treatment with the most potent of the three compounds, IRX5010, demonstrated dose response inhibition of in vivo growth of EMT-6 tumors. Inhibition of tumor growth at day 17 relative to vehicle was 59% and 69% respectively in mice treated with IRX5010 at 10 or 25 mg/kg/day. A cohort treated with 50 mg/kg/day was sacrificed early on day 12 due to excessive weight loss and deaths of some of the animals. This cohort experienced a 73% inhibition of tumor growth relative to vehicle. Gross necropsies of animals in the 25 and 50 mg/kg/day dose groups did not show observable pathologic findings in any major organ. Flow cytometry was performed on freshly excised tumors on the day of termination of the in-life portion of the study in the 10 and 25 mg/kg/day dose groups. Tumors from mice treated with IRX5010 had increased intratumoral numbers of Total CD45+ cells; Total CD3+, Total CD4+, and Total CD8+ T-cells per mg of tumor tissue, relative to vehicle controls. IRX5010 treated mice also had increased intratumoral CD4+IL-17+ T-helper cells; and increased CD4+CD62L- and CD8+CD62L- T-effector memory T-cells per mg of tumor tissue relative to vehicle-treated control mice. We also conducted an experiment of treatment with IRX5010 in mice transplanted with human immune cells (to provide a human immune system) to examine its effects on xenografted human Her2+ JIMT-1 cancer cells. In this model, treatment with IRX5010 at 10 mg/kg/day resulted in a 17% inhibition of tumor growth relative to vehicle control over 26 days of treatment. Flow cytometric analysis showed that tumors from the IRX5010 treated mice contained increased numbers per mg of tumor tissue of intratumoral human CD8+ T-cells, most of which were CD8+ CD7- CD45RA+ terminally differentiated effector memory phenotype T-cells. Conclusions: Treatment with IRX5010, a potent and highly selective RARγ nuclear receptor agonist compound demonstrated substantial treatment effects relative to vehicle control on inhibition of growth of murine triple negative breast cancer in vivo, despite having essentially no growth inhibitory effect on these cells in vitro. Treatment of xenografted human Her2+ tumors in mice with humanized immune systems resulted in a moderate inhibition of Her2+ breast cancer growth relative to vehicle controls. In both models, treatment with IRX5010 induced tumor infiltrating T-lymphocytes of largely effector memory phenotypes, demonstrating an effect on the tumor immune microenvironment. These data identify RARγ and RARγ agonists as a new treatment target and novel treatment modality for breast cancers, especially for the highly unmet need for new and better treatments for triple negative breast cancer. Citation Format: Martin Sanders, Mary Topalovski, Vidyasagar Vuligonda. IRX5010, a Highly Selective RARγ Nuclear Receptor Agonist Compound Inhibits In Vivo Growth of Murine EMT-6 Triple Negative Breast Cancer and Human JIMT-1Her2+ Breast Cancer By Induction of Tumor-Infiltrating Effector Memory T-cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-24-12.

Abstract PO1-13-04: Distinct immune signatures discriminate between patients defined as exceptional survivors of metastatic breast cancer compared to those with rapidly progressing treatment resistant breast cancers

Abstract Background: "Atypical responders" can encompass three sub- categories of patients: "exceptional responders" (those with an unusually favourable treatment response), "rapid progressors" (unusually poor or no response), and "exceptional/long-term survivors" (outlived initial prognosis). Here, we aim to investigate the drivers of immune surveillance mechanisms (local, lymphoid and peripheral) and the nature of immunological tumour recognition in exceptional survivors of stage 4 metastatic disease following standard-of-care chemo- and targeted therapies. Methods: We conducted a complementary multi-platform immune profiling study to define differences in the phenotypic immune landscape including mass-spectrometry-based proteomics on peripheral blood mononuclear cells (PBMCs), multiplex cytokine profiling of patient serum, and high-dimensional flow cytometry on whole blood samples. By staining 500μl of whole blood using 2 panels, 353 immune-cell-related parameters were obtained for comparisons among the following groups: "exceptional survivors," "exceptional responders," "rapid progressors," "non-exceptional metastatic patients," "early breast cancer patients," and "healthy volunteers". Patients were matched for age, breast cancer receptor status, and sites of metastases where possible. Results: Preliminary analysis of serum biomarkers and proteome of the PBMCs of the exceptional survivors showed elevated levels of NK-cell-related proteins such as KCTD10 and RBBP7. Flow cytometry analysis revealed the presence of increased activated CD56dim NK cells, CD56bright NK cells, and central memory (CM) (CD45RA-CD27+) CD8 T cells in both the exceptional survivors and the rapid progressors. However, expression of CD25 appears to be the main mode of activation in rapid progressors compared with increased NKG2D expression in exceptional survivors. Additionally, activation of the unconventional gd T cells was evident in both groups with terminally differentiated effector memory cells re-expressing CD45RA (TEMRA) Vd1 cell predominating in the exceptional survivors. In the rapid progressors, the increased CD25+ TEMRA Vd2 cells coupled with elevated serum IL-17A and IL-1b suggest their ability to generate IL-17. Th2 cytokines, IL-5 and IL-13 were also enriched in rapid progressors and concomitant increase in CD25+ Th2 cells reveals a strong Th2-driven immune signature in these patients. Finally increased CD86+ atypical double negative (DN) B cells, mostly comprised of the DN2 subset were also significantly enriched in the rapid progressors compared to the exceptional survivors where DN1 B cells were prevalent. Conclusion: The multi-platform approach to investigating immune responses present in atypical responders has identified several distinct immunophenotypes in which the extreme outliers differ in their potential immune surveillance mechanisms. Functional validation of these findings through activation and cytotoxicity assays is currently underway and future work aims to understand the spatial biology of these circulating immune cells within the context of their primary tumours, metastases, and lymph nodes. Citation Format: Helen Kakkassery, Thanussuyah Alaguthurai, Zuza Kozik, Paul Buckley, Ruifang Lu, Esme Carpenter, Rosalind Graham, Gheed Alhity, Farhana Hossain, Sadiyah Mukhtar, Syed Haider, Jyoti Choudhary, Sheeba Irshad. Distinct immune signatures discriminate between patients defined as exceptional survivors of metastatic breast cancer compared to those with rapidly progressing treatment resistant breast cancers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-13-04.

Abstract 1030: Zeb2 Regulates Senescence And Cytotoxic Phenotype In Atherosclerotic Plaque CD8 T Cells

Circulating senescent CD8 + CD57 + T cells have been implicated in reduced post-myocardial infarction survival and impaired glucose homeostasis in type 2 diabetes (T2D) patients. Despite these associations, their specific role in human atherosclerotic plaques, particularly in the context of aggravated plaque pathology in T2D remains unknown. In this study, we analyzed single-cell transcriptomic data from 75,049 immune cells obtained from plaques from 12 T2D and 10 no diabetes patients enrolled in the ATHERO-IN study. We identified 14 clusters of CD8 + T cells clusters, revealing distinct subsets such cytotoxic CD8 + T cells with a terminally differentiated effector memory phenotype, cytotoxic/exhausted, naïve/CM and regulatory CD8 + T cells. These clusters expressed varying degrees of senescent genes, with a notable heightened senescent transcriptional signature in T2D patients. Fibrocalcific plaques, which were prevalent in T2D patients, showed significantly enrichment in cytotoxic, inflammatory, naïve/CM, and interferon response CD8 T cell clusters. In contrast, fibroatheroma samples were predominantly enriched in MAIT-like CD8 T cells and cytotoxic/exhausted clusters. Aged CD8 T cells expanded in T2D patients exhibited elevated senescence and cytotoxic score, manifested a senescence-associated secretory phenotype expressing cytotoxic, pro-inflammatory and proatherogenic genes. Trajectory analysis and regulatory network analysis, highlighted ZEB2— a GWAS gene associated to coronary artery disease and myocardial infarction— as a potential transcription factor driving the senescence phenotype. CRISPR-based studies corroborated this, demonstrating that ZEB2 KO CD8 T cells reduced senescence, cytotoxicity, and activation markers, underscoring the pivotal role of ZEB2 in driving the terminal differentiation and aging phenotype. In conclusion, our findings shed light on the intricate interplay between senescent CD8+ T cells and atherosclerotic plaque pathology in the context of T2D. The identification of ZEB2 as a key regulator of T cell senescence offers a potential target for therapeutic interventions aimed at mitigating the senescence-associated effects on plaque pathology and cardiovascular outcomes in T2D patients.

Circulating Memory T Cells and TCF1+ T Cells Aid in Diagnosis and Monitor Disease Activity in Vitiligo

Vitiligo is an immune memory skin disease. T-cell factor 1 (TCF1) is essential for maintaining the maintenance of the memory T-cell pool. There is an urgent need to investigate the characteristics of peripheral memory T-cell profile and TCF1+ T-cell frequencies in patients with vitiligo patients. In this study, 31 patients with active vitiligo (AV), 22 with stable vitiligo (SV), and 30 healthy controls (HCs) were included. We measured circulating memory and TCF1+ T-cell frequencies using by flow cytometry. The Spearman’s rank test was used to evaluate the correlation correlations between cell frequencies and disease characteristics. Receiver operating characteristic curves (ROC) were constructed to investigate the discriminative power of the cell subpopulations. Circulating CD4+ and CD8+ terminally differentiated effector memory T-cell (TEMRA) frequencies were significantly higher in the AV group than in compared to HCs (P < 0.05). TCF1+ T-cell subpopulations were widespread increased in patients with vitiligo patients (P < 0.05). After adjusting adjustment for potential confounders, CD8+ and CD4+ central memory (TCM) cells, and CD8+ TEMRA were correlated with disease activity (P < 0.05). The combined diagnostic value of the four (naïve naive, effector memory, TCM, and TEMRA) CD8+TCF1+ T-cell subsets was relatively high (area under the ROC curve [AUC]AUC = 0.804, sensitivity = 71.70%, specificity = 83.34%), and the CD8+ T-cell subsets combination performed well in discriminating disease activity (AUC = 0.849, sensitivity = 70.97%, specificity = 90.91%). We demonstrated an altered circulating memory T-cell profile and increased TCF1+ T-cell percentage percentages in patients with vitiligo patients. T-cell subpopulations had a strong value values for vitiligo diagnosis and activity evaluation. This evidence presents a potential new pharmacological target for inhibiting to inhibit the autoimmunity that leads leading to vitiligo disease activity.

Immunophenotype of lymphocytes and real-world outcome of COVID-19 infection in children with hematology and oncology

BackgroundPatients with immunocompromise were suspected to encounter a high risk for severe coronavirus disease 2019 (COVID-19) infection on early period; however, data is lacking nowadays and immune response remain unclear.MethodsIn this retrospective study, internet questionnaire survey and medical records were acquired in pediatric hematology oncology patients. Clinical severity, immunological characteristics, and outcomes were analyzed from December 1, 2022 to January 31, 2023 at the 3rd year of pandemic in China.ResultsA total of 306 patients were included, with 21 patients (6.9%) asymptomatic, 262 (85.6%) mild severity, 17 (5.6%) moderate severity, 5 (1.6%) severe severity, and 1 (0.3%) critical severity. Seventy-eight (25.5%) patients were on intensive chemotherapy, and 32.0% children were on maintenance chemotherapy. Delays in cancer therapy occurred in 86.7% patients. Univariable analysis revealed active chemotherapy (P < 0.0001), long duration of symptom (P < 0.0001), low lymphocytes count (P = 0.095), low CD3 + and CD8 + T cell count (P = 0.013, P = 0.022), high percentage of CD4 + TCM (P = 0.016), and low percentage of transitional B cells (P = 0.045) were high risk factors for severe COVID-19 infection. Cox regression model showed that the absolute lymphocytes count (P = 0.027) and long duration of symptom (P = 0.002) were the independent factors for severity. Patients with CD8 + dominant and B cell depletion subtype wasn’t related with severity, but had higher percentage of CD8 + effector memory T cells (TEM) and terminally differentiated effector memory T cells (TEMRA) (P < 0.001, P < 0.001), and a longer COVID-19 duration (P = 0.045).ConclusionThe severity was relatively mild in children with immunodeficiencies in the third year of COVID-19 pandemic. Low lymphocyte count and long duration of symptom were the independent risk factors with COVID-19 severity. Delays in cancer care remain a major concern and the long outcome is pending.

Phenotypic and Immunological Characterization of Patients with Activated PI3Kδ Syndrome 1 Presenting with Autoimmunity

PurposeAutoimmunity is a significant feature of APDS1 patients. We aimed to explore the pathogenic immune phenotype and possible mechanisms of autoimmunity in APDS1 patients.MethodsThe clinical records and laboratory data of 42 APDS1 patients were reviewed. Immunophenotypes were evaluated by multiparametric flow cytometry. Autoantibodies were detected via antigen microarray analysis.ResultsA total of 42 children with PIK3CD gene mutations were enrolled. Immunological tests revealed increased proportions of effector memory cells (86%) and central memory cells (59%) among CD4+ T cells; increased proportions of effector memory cells (83%) and terminally differentiated effector memory T cells (38%) among CD8+ T cells. Fewer CD3+ T cells and B cells and higher IgG levels were reported in patients with autoimmunity. The proportion of Tregs was decreased, and the proportions of Th9, Tfh, and Tfr cells were increased in APDS1 patients. Among APDS1 patients, higher proportion of Th2 and Tfr cells were found in those with autoimmunity. The proportions of CD11c+ B and CD21lo B cells in patients with autoimmunity were significantly increased. Antigen microarray analysis revealed a wide range of IgG/IgM autoantibodies in patients with APDS1. In patients with autoimmunity, the proportion of Tfr might be positively correlated with autoantibodies.ConclusionsThe pathogenic immune phenotype of APDS1 patients included (1) deceased CD3+ T-cell and B-cell counts and increased IgG levels in patients with autoimmunity, (2) an imbalanced T helper cell subset, (3) increased proportions of autoreactive B cells, and (4) distinct autoantibody reactivities in patients with autoimmunity.