Memory Subsets Research Articles

OMIP-109: 45-color full spectrum flow cytometry panel for deep immunophenotyping of the major lineages present in human peripheral blood mononuclear cells with emphasis on the T cell memory compartment.

The need for more in-depth exploration of the human immune system has moved the flow cytometry field forward with advances in instrumentation, reagent development and availability, and user-friendly implementation of data analysis methods. We developed a high-quality human 45-color panel, for comprehensive characterization of major cell lineages present in circulation including T cells, γδ T cells, NKT-like cells, B cells, NK cells, monocytes, basophils, dendritic cells, and ILCs. Assay optimization steps are described in detail to ensure that each marker in the panel was optimally resolved. In addition, we highlight the outstanding discernment of cell activation, exhaustion, memory, and differentiation states of CD4+ and CD8+ T cells using this 45-color panel. The panel enabled an in-depth description of very distinct phenotypes associated with the complexity of the T cell memory response. Furthermore, we present how this panel can be effectively used for cell sorting on instruments with a similar optical layout to achieve the same level of resolution. Functional evaluation of sorted specific rare cell subsets demonstrated significantly different patterns of immunological responses to stimulation, supporting functional and phenotypic differences within the T cell memory subsets. In summary, the combination of full spectrum profiling technology and careful assay design and optimization results in a high resolution multiparametric 45-color assay. This panel offers the opportunity to fully characterize immunological profiles present in peripheral blood in the context of infectious diseases, autoimmunity, neurodegeneration, immunotherapy, and biomarker discovery.

Polarization of the memory B cell response.

Memory B cells are long-lived cells that are induced following infection or vaccination. Upon antigen re-encounter, memory B cells rapidly differentiate into antibody-secreting or germinal center B cells. While memory B cells are an important component of long-term protective immunity following vaccination, they also contribute to the progression of diseases such as autoimmunity and allergy. Numerous subsets of memory B cells have been identified in mice and humans that possess important phenotypic and functional differences. Here, we review the transcriptional circuitry governing memory B cell differentiation and function. We then summarize emerging evidence that the inflammatory environment in which memory B cells develop has an important role in shaping their phenotype and examine the pathways regulating the development of memory B cells during a type 1-skewed and type-2 skewed immune response.

CD4+ T cell help during early acute hepacivirus infection is critical for viral clearance and the generation of a liver-homing CD103+CD49a+ effector CD8+ T cell subset.

In hepatitis C virus (HCV) infection, CD4+ and CD8+ T cells are crucial for viral control. However, a detailed understanding of the kinetic of CD4+ T cell help and its role in the generation of different CD8+ T cell subsets during acute infection is lacking. The absence of a small HCV animal model has impeded mechanistic studies of hepatic antiviral T cell immunity and HCV vaccine development. In this study, we used a recently developed HCV-related rodent hepacivirus infection mouse model to investigate the impact of CD4+ T cell help on the hepatic CD8+ T cell response and viral clearance during hepacivirus infection in vivo. Our results revealed a specific kinetic of CD4+ T cell dependency during acute infection. Early CD4+ T cell help was essential for CD8+ T cell priming and viral clearance, while CD4+ T cells became dispensable during later stages of acute infection. Effector CD8+ T cells directly mediated timely hepacivirus clearance. An analysis of hepatic CD8+ T cells specific for two different viral epitopes revealed the induction of subsets of liver-homing CD103+CD49a+ and CD103-CD49a+ effector CD8+ T cells with elevated IFN-γ and TNF-α production. CD103+CD49a+ T cells further persisted as tissue-resident memory subsets. A lack of CD4+ T cell help and CD40L-CD40 interactions resulted in reduced effector functions and phenotypical changes in effector CD8+ T cells and a specific loss of the CD103+CD49a+ subset. In summary, our study shows that early CD4+ T cell help through CD40L signaling is essential for priming functional effector CD8+ T cell subsets, including unique liver-homing subsets, and hepacivirus clearance.

Targeting CD276 for T cell-based immunotherapy of breast cancer.

Breast cancer (BC) is the most common malignancy in women. Immunotherapy has revolutionized treatment options in many malignancies, and the introduction of immune checkpoint inhibition yielded beneficial results also in BC. However, many BC patients are ineligible for this T cell-based therapy, others do not respond or only briefly. Thus, there remains a high medical need for new therapies, particularly for triple-negative BC. CD276 (B7-H3) is overexpressed in several tumors on both tumor cells and tumor vessels, constituting a promising target for immunotherapy. We analyzed tumor samples of 25 patients using immunohistochemistry to assess CD276 levels. The potential of CC-3, a novel bispecific CD276xCD3 antibody, for BC treatment was evaluated using various functional in vitro assays. Pronounced expression of CD276 was observed in all analyzed tumor samples including triple negative BC. In analyses with BC cells, CC-3 induced profound T cell activation, proliferation, and T cell memory subset formation. Moreover, treatment with CC-3 induced cytokine secretion and potent tumor cell lysis. Our findings characterize CD276 as promising target and preclinically document the therapeutic potential of CC-3 for BC treatment, providing a strong rationale for evaluation of CC-3 in BC patients in a clinical trial for which the recruitment has recently started.

Higher frequency of peripheral blood CD103+CD8+ T cells with lower levels of PD-1 and TIGIT expression related to favorable outcomes in leukemia patients.

Leukemia is a prevalent pediatric life-threatening hematologic malignancy with a poor prognosis. Targeting immune checkpoints (ICs) to reverse T cell exhaustion is a potentially effective treatment for leukemia. Tissue resident memory T (TRM) cells have been found to predict the efficacy of programmed death receptor-1 inhibitor (anti-PD-1) therapy in solid tumors. However, the IC characteristics of TRM cells in leukemia and their relationship with prognosis remain unclear. We employed multi-color flow cytometry to evaluate the frequencies of CD103+CD4+ and CD103+CD8+ T cells in the peripheral blood (PB) of patients with acute myeloid leukemia and B-cell acute lymphoblastic leukemia compared to healthy individuals. We examined the expression patterns of PD-1 and T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) within the circulating CD103+ T cell subsets affected by leukemia. To further elucidate the immunological landscape, we assessed the differentiation status of CD103+ T cells across various disease states in patients with leukemia. Our findings showed a significant increase in the frequency of CD103+CD8+ T cells in the PB of patients with leukemia who had achieved complete remission (CR) compared to those in the de novo (DN) and relapsed/refractory (RR) stages. This increase was accompanied by a notable decrease in the expression levels of PD-1 and TIGIT in CD103+CD8+ T cells in the CR stage. Additionally, our analysis revealed a higher proportion of CD103+CD8+ T cells in the central memory (TCM) and effector memory (TEM) subsets of the immune profile. Notably, the proportions of CD103+ naïve T cells, CD103+ TEM, and CD103+ terminally differentiated T cells within the CD8+ T cell population were significantly elevated in patients with CR compared to those in the DN/RR stages. The data indicate that circulating higher frequency of CD103+CD8+ T cells with lower expression of PD-1 and TIGIT are associated with favorable outcomes in patients with leukemia. This suggests a potential role of TRM cells in leukemia prognosis and provides a foundation for developing targeted immunotherapies.

T cell responses and clinical symptoms among infants with congenital cytomegalovirus infection.

BACKGROUNDCongenital cytomegalovirus (cCMV) infection can cause developmental impairment and sensorineural hearing loss (SNHL). To determine the relationship between immune responses to cCMV infection and neurologic sequelae, T cell responses were compared for their connection to clinical symptoms at birth and neurodevelopmental outcomes.METHODSThirty cCMV-infected and 15 uninfected infants were enrolled in a single-center prospective observational case-control study. T cell pp65-specific cytokine responses; CD57, CD28, and PD-1 expression; and memory subsets were compared.RESULTSInfected neonates (73% symptomatic at birth) lacked pp65-specific cytokine-secreting T cells, with elevated frequencies of CD57+, CD28-, and PD-1+CD8+ T cells and effector memory subsets. Though frequencies overlapped between cCMV symptom groups, asymptomatic infants had higher frequencies of CD57+PD-1+CD8+ T cells. Neonates with subsequent developmental delay lacked detectable CMV-specific T cell responses, with patterns resembling those of uninfected infants. Two children with progressive SNHL had high frequencies of PD-1+CD8+ T cells over the first year compared with children without progressive SNHL.CONCLUSIONSimilar to published reports, neonatal viral antigen-specific cytokine-secreting T cell responses were not detected, but overall patterns indicate that globally differentiated memory CD8+ T cell populations were induced by cCMV infection, with higher frequencies of terminally differentiated PD-1+CD8+ T cells potentially associated with asymptomatic infection. In this cohort, a lack of in utero T cell differentiation was associated with developmental delay, and high frequencies of PD-1+CD8+ T cells persisted only in children with progressive SNHL. Further work is needed to define the specificity of these T cells and their mechanistic connection to these outcomes.FUNDINGThis study was funded through an intramural research award at Nationwide Children's Hospital, the Pediatric Infectious Disease Society Fellowship Award funded by Stanley and Susan Plotkin and Sanofi Pasteur, the Abigail Wexner Research Institute at Nationwide Children's Hospital, and the Pichichero Family Foundation Vaccines for Children Initiative Research Award from the Pediatric Infectious Diseases Society Foundation.

Identifying genetic variants associated with chromatin looping and genome function

Here we present a comprehensive HiChIP dataset on naïve CD4 T cells (nCD4) from 30 donors and identify QTLs that associate with genotype-dependent and/or allele-specific variation of HiChIP contacts defining loops between active regulatory regions (iQTLs). We observe a substantial overlap between iQTLs and previously defined eQTLs and histone QTLs, and an enrichment for fine-mapped QTLs and GWAS variants. Furthermore, we describe a distinct subset of nCD4 iQTLs, for which the significant variation of chromatin contacts in nCD4 are translated into significant eQTL trends in CD4 T cell memory subsets. Finally, we define connectivity-QTLs as iQTLs that are significantly associated with concordant genotype-dependent changes in chromatin contacts over a broad genomic region (e.g., GWAS SNP in the RNASET2 locus). Our results demonstrate the importance of chromatin contacts as a complementary modality for QTL mapping and their power in identifying previously uncharacterized QTLs linked to cell-specific gene expression and connectivity.

Abstract B034: Myeloperoxidase limits tumor-associated neutrophils mediated immunosuppression in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with a survival rate under 12%. Treatments like immunotherapy and chemotherapy are ineffective in PDAC due to the immunosuppressive tumor microenvironment, in which tumor-associated neutrophils (TANs) are a major component. TAN immunosuppression has been shown to depend upon increased production of reactive oxygen species, with myeloperoxidase (MPO) being a major source of it. We investigated the contribution of MPO in mediating TAN immunosuppression using orthotopic PDAC models in wild-type and syngeneic MPO-deficient mice. We observed a significant delay in tumor growth and improved clinical scores when MPO was deficient. Additionally, treatment with the MPO-specific inhibitor Verdiperstat also delayed tumor growth. Flow cytometry analysis of the tumor microenvironment further confirmed a significant increase in CD8 T and NK cells, along with an increase in granzyme B level in both subsets, when MPO was deficient. Additionally, there was an increase in activation marker (CD25) and memory subset among both CD8 and CD4 T cells in MPO-deficient mice. Ex vivo studies with isolated TANs from tumor-bearing mice showed reduced CD8 T and NK cell suppression, and reactive oxygen species level in absence of MPO, supporting the contribution of MPO in TAN immunosuppression. These data suggest that loss of MPO in TANs has decreased immunosuppressive functions resulting in increased cytotoxic and activated T cells and NK cells with increased memory response within the tumor microenvironment. Our results demonstrate the contribution of MPO in regulating tumor progression, TAN immunosuppression, and immune cell infiltration using an orthotopic PDAC model. Citation Format: Angisha Basnet, Brain Boone, Tracy Liu. Myeloperoxidase limits tumor-associated neutrophils mediated immunosuppression in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B034.

Categorically distinct subsets allow flexible memory selection in hybrid search.

In many everyday situations, we search our visual surroundings for any one of many memorized items held in memory, a process termed hybrid search. In some cases, only a portion of the memorized mental list is relevant within a specific visual context, thus, restricting memory search to the relevant subset would be desirable. Previous research had shown that participants largely fail to "partition" memory into several distinct subsets, on a trial-by-trial basis. However, given the known role of semantic content in long-term memory organization, we hypothesized that semantically defined subset categories might serve as a more powerful means for flexible memory selection in dynamic hybrid search situations. Experiment 1 revealed that, indeed, semantic characteristics (i.e., object category), but not perceptual features (e.g., arbitrary color), can provide a firm basis for flexible memory partitioning. Experiments 2 and 3 further showed that such memory partitioning is costless and is independent of the nature of the surrounding visual distractors (i.e., a categorically homogeneous or heterogeneous display). These findings demonstrate that confining one's memory search to a currently relevant subset of items is highly effective when the different memory subsets are defined by clear semantic categories. The results underscore the importance of conceptual information in the organization of activated long-term memory and in forming the basis for a flexible trial-by-trial memory selection. Our findings further highlight the relationship between visual search and memory search, and they may shed light on the processes contributing to a successful construction of bounded episodes in long-term memory. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Changes in Phenotypic and Molecular Features of Naïve and Central Memory T Helper Cell Subsets following SARS-CoV-2 Vaccination.

Molecular changes in lymphocytes following SARS-CoV-2 vaccination are incompletely understood. We hypothesized that studying the molecular (transcriptomic, epigenetic, and T cell receptor (TCR) repertoire) changes in CD4+ T cells following SARS-CoV-2 vaccination could inform protective mechanisms and refinement of future vaccines. We tested this hypothesis by reporting alterations in CD4+ T cell subsets and molecular features of CD4+ naïve and CD4+ central memory (CM) subsets between the unvaccinated and vaccinated groups. Compared with the unvaccinated, the vaccinated had higher HLA-DR expression in CD4+ T subsets, a greater number of differentially expressed genes (DEGs) that overlapped with key differentially accessible regions (DARs) along the chromatin linked to inflammasome activation, translation, regulation (of apoptosis, inflammation), and significant changes in clonal architecture beyond SARS-CoV-2 specificity. Several of these differences were more pronounced in the CD4+CM subset. Taken together, our observations imply that the COVID-19 vaccine exerts its protective effects via modulation of acute inflammation to SARS-CoV-2 challenge.

A comprehensive and longitudinal evaluation of the different populations of lymphoid and myeloid cells in the peripheral blood of patients treated with chemoradiotherapy for head and neck cancer

BackgroundImmunotherapy provided significant survival benefits for recurrent and metastatic patients with head and neck cancer. These improvements could not be reproduced in patients treated with curative-intent chemoradiotherapy (CRT) and the optimal radio-immunotherapy (RIT) concepts have yet to be designed. Exploration and analysis of the pre-therapeutic immune status of these patients and the changes occurring during the treatment course could be crucial in rationally designing future combined treatments.MethodsBlood samples were collected from a cohort of 25 head and neck cancer patients treated with curative-intended (C)-RT prior to therapy, after the first week of treatment, and three months after treatment completion. Peripheral blood mononuclear cells (PBMCs) or all nucleated blood cells were isolated and analyzed via flow cytometry.ResultsAt baseline, patients showed reduced monocyte and lymphocyte counts compared to healthy individuals. Although overall CD8+ T-cell frequencies were reduced, the proportion of memory subsets were increased in patients. Radiotherapy (RT) treatment led to a further increase in CD8+ effector memory T-cells. Among myeloid populations, tumor-promoting subsets became less abundant after RT, in favor of pro-inflammatory cells.ConclusionThe present study prospectively demonstrated a complex interplay and distinct longitudinal changes in the composition of lymphocytic and myeloid populations during curative (C)-RT of head and neck cancer. Further validation of this method in a larger cohort could allow for better treatment guidance and tailored incorporation of immunotherapies (IT) in the future.

Hepatitis B vaccine responders show higher frequencies of CD8+ effector memory and central memory T cells compared to non-responders.

Hepatitis B (HB) infection is a major global health problem. There is limited knowledge about HB vaccination-induced immune memory responses. We compared the frequency of CD8+ memory T cell subsets between responders (RSs) and non-responders (NRs) to HB vaccination. Blood samples were collected from RSs and NRs. PBMCs were cultured in the presence of Hepatitis B surface antigens (HBsAg) and PHA for 48 h to restimulate CD8+ memory T cells and T cell memory subsets were detected by flow cytometry using memory cell markers. The frequency of TEM, TCM, and TCM hi was significantly higher in responders compared to non-responders (p = 0.024, 0.022, and 0.047, respectively). Additionally, we report a positive correlation between the frequency of TEM cells in RSs with age and anti-HBsAb level (p = 0.03 and rs = 0.5; p = 0.01 and rs = 0.06). Responders display a higher level of CD8+ T cell-mediated immunity. Therefore, we suggest a possible defect in the formation of immunological CD8+ memory T cells in NRs and it may reduce antibody production compared to the RSs, although more experiments are needed.

Innate lymphoid cells in immunoglobulin E-mediated food allergy.

Recognition of the importance of innate lymphoid cells (ILCs) in the immune mechanisms of food allergy has grown in recent years. This review summarizes recent findings of ILCs in immunoglobulin E (IgE)-mediated food allergy. New research on ILCs in the context of the microbiome and other atopic diseases are also considered with respect to how they can inform understanding of the role of ILCs in food allergy. ILCs can mediate allergic and tolerogenic responses through multiple pathways. A novel subset of interleukin (IL)-10 producing ILC2s are associated with tolerance following immunotherapy to grass pollen, house dust mite allergy and lipid transfer protein allergy. ILC2s can drive food allergen-specific T cell responses in an antigen-specific manner. A memory subset of ILC2s has been identified through studies of other atopic diseases and is associated with effectiveness of response to therapy. The role of ILCs in food allergy and oral tolerance is relatively understudied compared to other diseases. ILCs can modulate immune responses through several mechanisms, and it is likely that these are of importance in the context of food allergy. Better understanding of theses pathways may help to answer fundamental questions regarding the development of food allergy and lead to novel therapeutic targets and treatment.

A comprehensive meta-analysis of tissue resident memory T cell shaping non-small-cell lung cancer immune microenvironment and patient prognosis.

210 Background: Tissue-resident memory T cells (TRM) are a specialized subset of long-lived memory T cells that reside in peripheral tissues. However, the impact of TRM-related immunosurveillance on the tumor-immune microenvironment (TIME) and tumor progression across various non-small-cell lung cancer (NSCLC) patient populations is yet to be elucidated. Methods: Our comprehensive analysis of multiple independent single-cell and bulk RNA-seq datasets of patient NSCLC samples generated reliable, unique TRM signatures, through which we inferred the abundance of TRM in NSCLC. A machine learning model was developed to prognosticate survival, tested in multiple independent NSCLC cohorts. Model performance was corroborated through Kaplan-Meier survival plots, receiver operating characteristic (ROC) curves, principal component analysis, and t-SNE analyses. Results: We discovered that TRM abundance is consistently positively correlated with CD4+ T helper 1 cells, M1 macrophages, and resting dendritic cells in the TIME. In addition, TRM signatures are strongly associated with immune checkpoint genes and the prognosis of NSCLC patients. A TRM-based machine learning model to predict patient survival was validated and an 18-gene risk score was further developed to effectively stratify patients into low-risk and high-risk categories, wherein patients with high-risk scores had significantly lower overall survival than patients with low-risk. The prognostic value of the risk score was independently validated by the TCGA dataset and multiple independent NSCLC patient datasets. Notably, low-risk NSCLC patients with higher TRM infiltration exhibited enhanced T-cell immunity, nature killer cell activation, and other TIME immune responses related pathways, indicating a more active immune profile benefitting from immunotherapy. However, the TRM signature revealed low TRM abundance and a lack of prognostic association among lung squamous cell carcinoma patients in contrast to adenocarcinoma, indicating that the two NSCLC subtypes are driven by distinct TIMEs. Conclusions: Altogether, this study provides valuable insights into the complex interactions between TRM and TIME and their impact on NSCLC patient prognosis. The development of a simplified 18-gene risk score provides a practical prognostic marker for risk stratification. Keywords: Tissue resident memory T cell, non-small-cell lung cancer, prognosis, tumor immune microenvironment, machine learning.

Historicizing Brati: A Journey of Sujata’s Memories in Mahasweta Devi’s Mother of 1084

Mahasweta Devi’s Mother of 1084 has a trope of returning to the past events, after a tragedy. This trope is central to both the plot and act of narration of the protagonist, Sujata. Sujata’s journey to the past is not just part of a thematic element, but also a narrative strategy through which Mahasweta Devi casts an indirect gaze on the Naxalite world. This study analyses Sujata’s trip into the past by focusing on different subsets of memory involved in her journey which Mahasweta Devi employs throughout the novel. Devi’s Mother of 1084 entirely is a narrative from the perspective of a bereaved Sujata after having lost her son Brati to unknown circumstances. By referring to the theoretical underpinnings of renowned scholars from the field of Memory Studies, including Jacques Lacan, Endel Tulving, Chris Brewin, and Kurt Danziger, this study explores how different memory subsets that of recollection, reminiscence, episodes, semantics, and flashbacks of the characters in the novel come together to historicise the memory of the deceased (Brati). The study then attempts to understand memory’s role as the focal point in bringing an artistic sense to the novel.

Prospective Study of the Recovery of CD4+ T cell Subsets and Their Relationship to the Overall Survival Following Allogeneic Hematopoietic Stem Cell Transplantation.

The immune recovery (IR) following the allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an advancement procedure that fundamentally correlated to the curative success. It is critical to understand the interfering factors in IR to prevent the HSCT-related mortality. The factors influencing CD4+T cell recovery post (HSCT) are not well totally characterized. This work was conducted to analyze the kinetics of CD4+T cell subsets recovery post HSCT, and to correlate their reconstitution with different factors that may influence the overall survival following HSCT. We prospectively evaluated the clinical outcomes and CD4+ T lymphocyte subtypes regeneration kinetics at different time-points of 22 patients with allogeneic HSCT for malignant and non-malignant diseases from 2007 to 2008. Statistics (means, minimal, and maximal values) were used to describe patient baseline characteristics. Results were presented as absolute count of CD4+ T cells, % of naive and memory subsets, and p-values. Thymus-independent pathways were responsible for the rapid recovery of memory CD4+T cells less than 6 months after HSCT. Thymus-dependent pathways were activated between 6 and 12 months in the majority of patients with increasing counts of naive CD4+ T cell. Furthermore, increasing patient age and chronic GVHD predicted the slow naive T cell recovery and also predicted high memory T cell numbers. The proper CD4 + reconstitution was associated with younger age, a non-malignant disease and a lower incidence of acute graft-versus-host disease ≥ grade 2. Additionally, the CD4+ T lymphocytes recovery ≥ 200/µl was associated with a higher overall survival. Different factors affected the IR post the allo-HSCT. The CD4+ count ≥ 200/µl was a simple IR predictor of overall survival and better clinical outcome following allogeneic HSCT.

Immune reconstitution and cidofovir administration rescue human adenovirus hepatitis after allogeneic hematopoietic cell transplantation

Human adenovirus infection (HAdV) may be fatal in patients undergoing allogeneic hematopoietic cell transplantation (HCT). Cidofovir is effective in only a part of the post-HCT HAdV infection. Therefore, posttransplant immune reconstitution is important for HAdV clearance. We describe the detailed immune reconstitution and response of adenovirus-specific T cells in a patient with inborn errors of immunity who had disseminated HAdV infection with hepatitis post-HCT and was treated with cidofovir.Though the patient received cidofovir for only 19 days starting from Day 72 after HCT because of renal dysfunction, we observed T-cell reconstitution, a decrease in HAdV copy number, and amelioration of the symptoms of HAdV infection after Day 90. We initially observed expanded NK and CD8+CD45RO+ memory subsets and later gradual increase of naïve T cells eveloped after cessation of cidofovir treatment. An increase in adenovirus-specific IFN-γ secretion from 2 to 4 months after HCT was confirmed by ELISpot assay.The progression of immune reconstitution and cidofovir treatment are considered to have contributed to survival in this patient. Optimization of transplantation methods, prompt appropriate antiviral medication, and virus-specific T-cell therapy would be necessary as the better strategy for systemic HAdV infection.

Cellular heterogeneity and key subsets of tissue-resident memory T cells in cervical cancer

Tissue-resident memory T cells (TRMs) play a critical role in cancer immunity by offering quick and effective immune responses. However, the cellular heterogeneity of TRMs and their significance in cervical cancer (CC) remain unknown. In this study, we generated and analyzed single-cell RNA sequencing data from 12,945 TRMs (ITGAE+CD3D+) and 25,627 non-TRMs (ITGAE−CD3D+), derived from 11 CC tissues and 5 normal cervical tissues. We found that TRMs were more immunoreactive than non-TRMs, and TRMs in CC tissues were more activated than those in normal cervical tissues. Six CD8+ TRM subclusters and one CD4+ TRM subcluster were identified. Among them, CXCL13+ CD8+ TRMs were more abundant in CC tissues than in normal cervical tissues, had both cytotoxic and inhibitory features, and were enriched in pathways related to defense responses to the virus. Meanwhile, PLAC8+ CD8+ TRMs were less abundant in CC tissues than in normal cervical tissues but had highly cytotoxic features. The signature gene set scores of both cell subclusters were positively correlated with the overall survival and progression-free survival of patients with CC following radiotherapy. Of note, the association between HLA-E and NKG2A, either alone or in a complex with CD94, was enriched in CXCL13+ CD8+ TRMs interacting with epithelial cells at CC tissues. The in-depth characterization of TRMs heterogeneity in the microenvironment of CC could have important implications for advancing treatment and improving the prognosis of patients with CC.

Long-lived central memory γδ T cells confer protection against murine cytomegalovirus reinfection.

The involvement of γδ TCR-bearing lymphocytes in immunological memory has gained increasing interest due to their functional duality between adaptive and innate immunity. γδ T effector memory (TEM) and central memory (TCM) subsets have been identified, but their respective roles in memory responses are poorly understood. In the present study, we used subsequent mouse cytomegalovirus (MCMV) infections of αβ T cell deficient mice in order to analyze the memory potential of γδ T cells. As for CMV-specific αβ T cells, MCMV induced the accumulation of cytolytic, KLRG1+CX3CR1+ γδ TEM that principally localized in infected organ vasculature. Typifying T cell memory, γδ T cell expansion in organs and blood was higher after secondary viral challenge than after primary infection. Viral control upon MCMV reinfection was prevented when masking γδ T-cell receptor, and was associated with a preferential amplification of private and unfocused TCR δ chain repertoire composed of a combination of clonotypes expanded post-primary infection and, more unexpectedly, of novel expanded clonotypes. Finally, long-term-primed γδ TCM cells, but not γδ TEM cells, protected T cell-deficient hosts against MCMV-induced death upon adoptive transfer, probably through their ability to survive and to generate TEM in the recipient host. This better survival potential of TCM cells was confirmed by a detailed scRNASeq analysis of the two γδ T cell memory subsets which also revealed their similarity to classically adaptive αβ CD8 T cells. Overall, our study uncovered memory properties of long-lived TCM γδ T cells that confer protection in a chronic infection, highlighting the interest of this T cell subset in vaccination approaches.

A comprehensive meta-analysis of tissue resident memory T cells and their roles in shaping immune microenvironment and patient prognosis in non-small cell lung cancer.

Tissue-resident memory T cells (TRM) are a specialized subset of long-lived memory T cells that reside in peripheral tissues. However, the impact of TRM-related immunosurveillance on the tumor-immune microenvironment (TIME) and tumor progression across various non-small-cell lung cancer (NSCLC) patient populations is yet to be elucidated. Our comprehensive analysis of multiple independent single-cell and bulk RNA-seq datasets of patient NSCLC samples generated reliable, unique TRM signatures, through which we inferred the abundance of TRM in NSCLC. We discovered that TRM abundance is consistently positively correlated with CD4+ T helper 1 cells, M1 macrophages, and resting dendritic cells in the TIME. In addition, TRM signatures are strongly associated with immune checkpoint and stimulatory genes and the prognosis of NSCLC patients. A TRM-based machine learning model to predict patient survival was validated and an 18-gene risk score was further developed to effectively stratify patients into low-risk and high-risk categories, wherein patients with high-risk scores had significantly lower overall survival than patients with low-risk. The prognostic value of the risk score was independently validated by the Cancer Genome Atlas Program (TCGA) dataset and multiple independent NSCLC patient datasets. Notably, low-risk NSCLC patients with higher TRM infiltration exhibited enhanced T-cell immunity, nature killer cell activation, and other TIME immune responses related pathways, indicating a more active immune profile benefitting from immunotherapy. However, the TRM signature revealed low TRM abundance and a lack of prognostic association among lung squamous cell carcinoma patients in contrast to adenocarcinoma, indicating that the two NSCLC subtypes are driven by distinct TIMEs. Altogether, this study provides valuable insights into the complex interactions between TRM and TIME and their impact on NSCLC patient prognosis. The development of a simplified 18-gene risk score provides a practical prognostic marker for risk stratification.