Memory T Cells Research Articles

Booster COVID-19 mRNA vaccination ameliorates impaired B-cell but not T-cell responses in older adults

Age-associated differences in the effect of repetitive vaccination, particularly on memory T-cell and B-cell responses, remain unclear. While older adults (aged ≥65 years) exhibited enhanced IgG responses following COVID-19 mRNA booster vaccination, they produced fewer spike-specific circulating follicular helper T cells-1 than younger adults. Similarly, the cytotoxic CD8+ T-cell response remained diminished with reduced PD-1 expression even after booster vaccination compared with that in younger adults, suggesting impaired memory T-cell activation in older adults. In contrast, although B-cell responses in older adults were weaker than those in younger adults in the primary response, the responses were significantly enhanced upon booster vaccination, reaching levels comparable with that observed in younger adults. Therefore, while booster vaccination ameliorates impaired humoral immunity in older adults by efficiently stimulating memory B-cell responses, it may less effectively enhance T-cell-mediated cellular immunity. Our study provides insights for the development of effective therapeutic and vaccine strategies for the most vulnerable older population.

CD45RO-Positive Memory T-Cell Density in the Tumoral Core and Invasive Margin Predict Long-Term Survival in Esophageal Squamous Cell Carcinoma.

The association between tumor-infiltrating lymphocytes and tumor immunity has long been recognized. Among T-cell types, CD45RO-positive memory T cells (CD45RO+) are reported to correlate with survival in several cancer types, but clinical evidence is lacking in esophageal squamous cell carcinoma (ESCC). In surgical specimens from 162 preoperatively untreated patients, immunohistochemistry for CD45RO was performed to evaluate the density of CD45RO+ in the tumor core (CT) and invasive margin (IM) using an auto-count method. Patients were classified into high- versus low-CD45RO+ groups based on CD45RO+ density in CT and IM separately and combined. The relationship between CD45RO+ density and clinicopathological factors, including prognosis, was evaluated. Average CD45RO+ density was 133/mm2 in CT and 372/mm2 in IM. No significant differences in clinicopathological factors according to high- versus low-CD45RO+ scores were identified. Using CT scores, the CD45RO+-high group had a better 5-year overall survival (OS) rate (77.2% vs. 54.7% CD45RO+-low, P = 0.0433), but OS rates did not differ statistically between the two groups by IM scores (75.7% vs. 50.3%, P = 0.0576). Using immunohistochemical scores for CT+IM, the survival difference was significant, with a 5-year OS rate of 73.7% for the CD45RO+-high group versus 46.3% for the CD45RO+-low group (P = 0.0141). Multivariate analysis identified CD45RO+ CT+IM density as an independent prognostic variable in OS (hazard ratio 2.27, 95% confidence interval 1.43-3.62, P = 0.0006). Density of CD45RO+ expression in the CT and IM might be a predictor of long-term survival in ESCC.

Unique lymphocyte transcriptomic profiles in septic patients with chronic critical illness.

Despite continued improvement in post-sepsis survival, long term morbidity and mortality remain high. Chronic critical illness (CCI), defined as persistent inflammation and organ injury requiring prolonged intensive care, is a harbinger of poor long-term outcomes in sepsis survivors. Current dogma states that sepsis survivors are immunosuppressed, particularly in CCI. Investigation of this immune suppression in heterogeneous immune populations across distinct clinical trajectories and outcomes, along with limited sampling access, is accessible via single-cell RNA sequencing (scRNA-seq). scRNA-seq analysis was performed on healthy subjects (n=12), acutely septic patients at day 4 ± 1 (n=4), and those defined as rapid recovery (n=4) or CCI (n=5) at day 14-21. Differential gene expression and pathway analyses were performed on peripheral blood lymphocytes at both a population and annotated cell subset level. Cellular function was assessed via enzyme-linked immunosorbent spot (ELISpot), cytokine production analysis, and T-cell proliferation assays on an additional cohort of septic patients (19 healthy, 68 acutely septic, 27 rapid recovery and 20 classified as CCI 14-21 days after sepsis onset). Sepsis survivors that developed CCI exhibited proportional shifts within lymphoid cell populations, with expanded frequency of CD8+ and NK cells. Differential expression and pathway analyses revealed continued activation in T cells and NK cells, with generalized suppression of B-cell function. Both T and NK cell subsets displayed transcriptomic profiles of exhaustion and immunosuppression in CCI, particularly in CD8+ T effector memory (TEM) cells and NK cells. Functional validation of T-cell behavior in an independent cohort demonstrated T cells maintained proliferative responses in vitro yet exhibited a marked loss of cytokine production. IFN-γ production at the acute phase (day 4 ± 1) was significantly reduced in subjects later classified as CCI. Sepsis patients exhibit unique T-, B-, and NK-cell transcriptional patterns that are both time- and clinical trajectory-dependent. These transcriptomic and pathway differences in sepsis patients that develop CCI are associated with exhaustion in CD8+ TEM cells and NK cells. Understanding the specific immune system patterns of different cell subsets after sepsis at a molecular level will be key to the development of personalized immunotherapy and drug-targeting intervention. https://clinicaltrials.gov/, identifier NCT02276417.

029 Stratified IL-9 secretion by memory T-cell in AD patients is tissue-tropic diverse

029 Stratified IL-9 secretion by memory T-cell in AD patients is tissue-tropic diverse

Elevated Soluble ACE2 Activity in Children and Adults After SARS-CoV-2 Exposure Irrespective of Laboratory-Confirmed Infection.

The pivotal role of the cell entry receptor ACE2 for SARS-CoV-2 infection is well-established. When ACE2 is shed from cell surface into plasma as soluble ACE2 (sACE2), it can effectively neutralize SARS-CoV-2. This longitudinal prospective cohort study analyzed sACE2 activity in 1192 participants, aged 4 months to 81 years, 3 and 12 months after SARS-CoV-2 household exposure. Following SARS-CoV-2 exposure, participants exhibited significantly elevated sACE2 activity, irrespective of confirmed infection, with the highest levels observed in exposed children. Longitudinal analysis revealed a decline in sACE2 levels over time, reaching levels comparable to age- and sex-matched pre-pandemic controls. An increase in sACE2 activity was also confirmed in vitro in Calu-3 (human lung) cells within hours of SARS-CoV-2 exposure, providing a direct link between SARS-CoV-2 exposure and elevated sACE2. This study, therefore, challenges the dichotomy of categorizing SARS-CoV-2 exposed participants as infected or not infected solely on currently established diagnostic assays. It demonstrates lasting host responses independent of B- and T-cell memory and may help to keep SARS-CoV-2 infections in balance and contribute to successful virus clearance in children and adults lacking humoral and cellular immune responses following SARS-CoV-2 exposure. Trial Registration: German Registry for Clinical Studies; Identifier: D 00021521.

Causal associations between telomere length and pulmonary arterial hypertension: A two-sample Mendelian randomization study

Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by elevated pulmonary artery pressure, leading to right heart failure, and mortality. The role of telomere length, a marker of biological aging, in PAH remains unclear. We utilized summary-level data from genome-wide association studies for various measures of telomere length and PAH. Single nucleotide polymorphisms associated with telomere length at a genome-wide significance level were used as instrumental variables. The inverse variance weighted method was the primary analysis, with sensitivity analyses including the weighted median and Mendelian randomization-Egger regression. The odds ratios and 95% confidence intervals (CI) were calculated to estimate the causal effect of telomere length on PAH risk. The Mendelian randomization analyses revealed no significant causal association between overall telomere length and PAH (odds ratios per standard deviation increase = 1.229, 95% CI: 0.469–3.222, P = .676). Similar null findings were observed for granulocyte, lymphocyte, naive T-cell, memory T-cell, B-cell, and natural killer-cell telomere lengths. Sensitivity analyses confirmed the robustness of the results, with no evidence of horizontal pleiotropy or significant influence of individual single nucleotide polymorphisms on the overall estimates. This Mendelian randomization study didn’t support a causal association between telomere length and PAH.

CTIM-27. DOC1021 CELL-BASED VACCINATION AS ADJUVANT THERAPY FOR GLIOBLASTOMA: PHASE I CLINICAL TRIAL ANALYSIS

Abstract Glioblastoma is an aggressive tumor for which median survival remains 14-18 months despite aggressive standard of care. Cellular immunotherapy approaches have recently shown promise. Homologous antigenic loading is an ex-vivo technique that leverages p38MAPK and mTORC1 signaling cascades to initiate powerful cDC1-like skewing in monocyte-derived dendritic cells, leading to downstream induction of tissue-infiltrating, cytolytic effector memory T-cells. This open-label phase I clinical trial evaluated the autologous dendritic cell vaccine DOC1021 prepared through homologous antigenic loading and administered bilaterally near the deep cervical lymph nodes. Three courses of vaccine were administered every 2 weeks after completion of chemoradiation, adjuvanted concurrently with six weeks of weekly type I interferon. Four dose levels from 3.5x106 to 3.6x107 total vaccine cells were tested. Tumor progression prior to vaccination was not an exclusion criterion. Sixteen newly diagnosed IDH-WT patients completed treatment, median age 63 years and 94% MGMTp unmethylated. The most common related AEs were grade 1 injection-site reactions and grade 1-3 fatigue and urticaria. No DLTs were observed. Immunohistochemistry of tumors derived from early post-vaccination second resections showed enhanced CD8+ T-cell infiltration and pathologic findings consistent with residual rather than relapsed GBM in 2/3 patients. Analysis of post-vaccination PBMC in dose level cohorts 2-4 indicated expansion of both CD4+ (13/13) and CD8+ (11/13) central memory T-cell compartments (p<0.002 and p<0.05, respectively) as well as expansion of CD8+CD127+ T-cells (12/13; p<0.001). Among three patients for whom tissue was obtained pre- and post-vaccination, clinical outcomes correlated with Visium spatial transcriptomic analysis. Median survival for the MGMTp unmethylated cohort (n=15) has not yet been reached but is statistically greater (p<0.05) than that of matched historic controls. The results indicate that DOC1021 is safe, can be effectively integrated within existing standards of care and is potentially efficacious in a challenging patient population.

Inactivated Toxoplasma gondii nanovaccine boosts T-cell memory response in a seropositive yellow-footed rock wallaby (Petrogale xanthopus) – A case report from Copenhagen Zoo

Toxoplasma gondii is a ubiquitous parasite causing significant mortality in captive wildlife, especially marsupials. Historically, treatment has been unrewarding and no vaccine was available. An intranasal vaccine based on purified inactivated T. gondii was developed for toxoplasmosis prevention. A vaccination campaign started in early 2017 and was successful in preventing toxoplasma-related mortality in marsupials in many European and South American zoos. Amongst the vaccinated wallabies, about 30% were T. gondii seropositive before the vaccination, and no toxoplasma-related deaths were observed since the administration of the vaccine. The objective of this case study was to assess the potential effect of the vaccination on a seropositive wallaby. It is important to note that this vaccine doesn't induce any humoral response in sheep, and squirrel monkeys but induces a strong T-cell response. A T. gondii seropositive Yellow-footed rock wallaby (Petrogale xanthopus) from Copenhagen Zoo received two doses of the aforementioned intranasal vaccine. Blood samples were collected before each vaccination and used for peripheral blood mononuclear cell isolation. The impact of the vaccination on the lymphocyte phenotype was characterized by flow cytometry. Cell size, represented by forward scatter, and granularity, represented by side scatter parameters were analyzed. Two doses of the vaccine induced a respective 30.1 and 25.6% increase in cell size and granularity in lymphocytes stimulated with T. gondii antigens, as assessed by flow cytometry. These changes were likely correlated with T-cell activation, which indicates that two doses of the vaccine might have boosted the already-existing T-cell memory response against T. gondii in a seropositive animal. No morphological changes were observed in lymphocytes from an unvaccinated seronegative wallaby. This is the first documented case of boosting an already-existing cellular immune response against toxoplasmosis by the vaccine in a seropositive Yellow-footed rock wallaby.

Maintenance and functional regulation of immune memory to COVID-19 vaccines in tissues.

Memory T and B cells in tissues are essential for protective immunity. Here, we performed a comprehensive analysis of the tissue distribution, phenotype, durability, and transcriptional profile of COVID-19 mRNA vaccine-induced immune memory across blood, lymphoid organs, and lungs obtained from 63 vaccinated organ donors aged 23-86, some of whom experienced SARS-CoV-2 infection. Spike (S)-reactive memory Tcells were detected in lymphoid organs and lungs and variably expressed tissue-resident markers based on infection history, and S-reactive B cells comprised class-switched memory cells resident in lymphoid organs. Compared with blood, S-reactive tissue memory Tcells persisted for longer times post-vaccination and were more prevalent with age. S-reactive Tcells displayed site-specific subset compositions and functions: regulatory cell profiles were enriched in tissues, while effector and cytolytic profiles were more abundant in circulation. Our findings reveal functional compartmentalization of vaccine-induced Tcell memory where surveilling effectors and in situ regulatory responses confer protection with minimal tissue damage.

Synovial tissue myeloid dendritic cell subsets exhibit distinct tissue-niche localization and function in health and rheumatoid arthritis.

Current rheumatoid arthritis (RA) treatments do not restore immune tolerance. Investigating dendritic cell (DC) populations in human synovial tissue (ST) may reveal pathways to reinstate tolerance in RA. Using single-cell and spatial transcriptomics of ST biopsies, as well as co-culture systems, we identified condition- and niche-specific DC clusters with distinct functions. Healthy tissue contained tolerogenic AXL+ DC2s in the lining niche. In active RA, the hyperplasic lining niche was populated with inflammatory DC3s that activated CCL5-positive effector memory Tcells, promoting synovitis. Lymphoid niches that emerged in the sublining layer were enriched with CCR7+ DC2s, which interacted with naive Tcells, potentially driving the local expansion of new effector Tcells. Remission saw the resolution of these pathogenic niches but lacked recovery of tolerogenic DC2s and exhibited activation of blood precursors of ST-DC3 clusters prior to flare-ups. Targeting pathogenic DC3s or restoring tolerogenic DC2s may help restore immune homeostasis in RA joints.

Long-term immunological changes after corrective cardiacsurgery.

Infants with congenital heart disease (CHD) often undergo thymectomy during corrective cardiac surgery (CCS). The long-term immunological effects remain controversial, with concerns regarding increased susceptibility to infections, allergies, autoimmunity due to compromised immune tolerance mechanisms. This study aims to elucidate the long-term immunological effects of early thymectomy. We enrolled 22 patients who underwent thymectomy in infancy and were followed up in the Pediatric Allergy and Immunology Clinic at Marmara University. We performed demographic characteristics and detailed immunological evaluation, including immunoglobulins, vaccine responses, lymphocyte subset analyses, upregulation, proliferation of T cells and T-cell receptor excision circles (TRECs). Sixteen patients had a history of infection, including six serious infections, all in the first year. Lymphopenia was observed in 27% of patients, with a significant decrease in naive CD4+ and recent thymic emigrant T cells counts and an increase in the proportion of memory T-cells, indicating premature immune senescence. Low levels of IgG, IgA and IgM were found in 36%, 40% and 22% of patients respectively. Vaccine responses were positive in 90% of patients. TREC levels were low in all 10 patients analysed. Seven of nine patients had normal proliferation. Twenty-two percent of patients had allergic disease, and autoimmunity was not observed. Early thymectomy leads to permanent immunological changes that are indicative of early immunosenescence. It is recommended to preserve thymic tissue during surgery and requires long-term follow-up in terms of findings such as allergy and autoimmunity as well as infections due to impaired immune tolerance mechanisms.

Evaluation of adenoviral vector Ad19a encoding RSV-F as novel vaccine against respiratory syncytial virus

Respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infections in infants and toddlers. Since natural infections do not induce persistent immunity, there is the need of vaccines providing long-term protection. Here, we evaluated a new adenoviral vector (rAd) vaccine based on the rare serotype rAd19a and compared the immunogenicity and efficacy to the highly immunogenic rAd5. Given as an intranasal boost in DNA primed mice, both vectors encoding the F protein provided efficient protection against a subsequent RSV infection. However, intramuscular immunization with rAd19a vectors provoked vaccine-enhanced disease after RSV infection compared to non-vaccinated animals. While mucosal IgA antibodies and tissue-resident memory T-cells in intranasally vaccinated mice rapidly control RSV replication, a strong anamnestic systemic T-cell response in absence of local immunity might be the reason for immune-mediated enhanced disease. Our study highlighted the potential benefits of developing effective mucosal against respiratory pathogens.

A minority of proliferating human CD4+ T cells in antigen-driven proliferation assays are antigen specific.

Antigen-driven T-cell proliferation is often measured using fluorescent dye dilution assays, such as the CFSE-based proliferation assay. Dye dilution assays have been powerful tools to detect human CD4+ T-cell responses, particularly against autoantigens. However, it is not known how many cells within the proliferating population are specific for the stimulating antigen. Here we determined the frequency of CD4+ T cells specific for the stimulating antigen within the antigen-responsive population of CFSE-based proliferation assays. We compared CD4+ T-cell responses to a type 1 diabetes autoantigen (proinsulin C-peptide) and to a vaccine antigen (tetanus toxoid). The TCRs expressed by antigen-responsive CD4+ T cells were sequenced, and their antigen specificity was tested functionally by expressing them in a reporter T-cell line. Responses to C-peptide were weak, but detectable, in PBMC from individuals with T1D, whereas responses to tetanus toxoid were much stronger. The frequency of antigen-specific CD4+ T cells correlated with the strength of the response to antigen in the proliferation assay. However, antigen-specific CD4+ T cells were rare among antigen-responsive CD4+ T cells. For C-peptide, an average frequency of 7.5% (1%-11%, n = 4) of antigen-responsive CD4+ T cells were confirmed to be antigen specific. In the tetanus-toxoid-stimulated cultures, on average, 45% (16%-78%, n = 5) of the antigen-responsive CD4+ T cells were tetanus toxoid specific. These data show that antigen-specific CD4+ T cells are a minority of the cells that proliferate in response to antigen and have important implications for in vitro CD4+ T-cell proliferation assays.

Self-Adjuvanting Adenoviral Nanovaccine for Effective T-Cell-Mediated Immunity and Long-Lasting Memory Cell Activation against Tuberculosis.

An enhanced vaccine is immediately required to swap the more than 100 year-old bacillus Calmette-Guerin (BCG) vaccine against tuberculosis. Here, trimethyl chitosan-loaded inactivated Mycobacterium smegmatis (MST), along with potent adenovirus hexon protein (AdHP), and toll-like receptor (TLR)-1/2 as a nanovaccine, was developed against tuberculosis (TB). The nanoformulation increased the bioavailability of MST and elicited the targeting ability. Nanovaccines have a size range of 183.5 ± 9.5 nm with a spherical morphology and uniform distribution. The nanovaccine exhibited a higher release of antigen in acidic pH, and this is mainly due to protonation of ionizable groups in polymeric materials. The nanovaccine facilitated the effective cellular uptake of bone-marrow-derived dendritic cells and progressive endosomal escape in a shorter period. In vitro analyses indicated that the nanovaccine activated cytokine and T-cell production and also assisted in humoral immunity by producing antibodies. The nanovaccine was able to induce more cellular and humoral memory cells and a better protective immune response. Nanomaterials effectively delivered the MST, AdHP, and TLR1/2 antigens to the major histocompatibility complex class I and II pathways to generate protective cytotoxic CD8+ and CD4+ T-cells. In vivo experiments, compared with free MST and BCG, showed that mice immunized with the nanovaccine induced more specific CD4+, CD8+, and memory T-cell activations. Overall, the fabricated nanovaccine was able to control the release of antigens and adjuvants and enhance memory cell activation and humoral immunity against TB.

Bioinformatics approach to identifying potential cancer-associated mutations in CCL2

Chemokine C-C motif ligand 2 (CCL2), also known as monocyte chemoattractant protein 1 or small inducible cytokine A2, is a cytokine from the CC chemokine family. It plays a crucial role in recruiting monocytes, memory T-cells, and dendritic cells to inflammatory sites resulting from tissue injury or infection. C-C motif chemokine receptor 2 (CCR2) is a chemokine receptor that may influence lymphocyte function. The interaction between CCL2 and CCR2 is essential for inflammatory responses and cancer regulation, as it attracts monocytes and macrophages to tumor sites, facilitating tumor growth and metastasis. Given the importance of CCL2 in regulating cell trafficking and cancer progression, we employed a bioinformatics approach to examine the effects of oncogenic missense mutations in CCL2 on CCR2 activation. We used precise computational methods to identify the molecular characteristics responsible for the altered activity and interactions, thereby enhancing our understanding of the molecular mechanisms underlying disease progression. We generated a three-dimensional model of the CCL2 protein with the identified mutations using the I-TASSER algorithm. The effects of these mutations on the protein’s stability and functional properties were evaluated using various prediction tools, and molecular dynamics simulations were conducted using WebGro software. Our analysis of 83 CCL2 missense mutations identified 10 disease-causing mutations, including C59G, which was directly linked to cancer. The C59G mutation increases the binding interaction between CCL2 and CCR2. The C59G position was determined to be highly conserved, and substitutions of cysteine (C) 59 with glycine (G) altered CCL2 activity. Our results suggest that this mutation alters the CCL2–CCR2 binding activity, lowering the risk of developing cancer and defending against pathogen invasion during the neutrophil-mediated innate immune response.

In vitro impacts of glyphosate on manatee lymphocytes

Exposure to contaminants, such as the herbicide glyphosate, can suppress protective immune functions. Glyphosate is the herbicide most used worldwide and has been found in the plasma of more than 50 % of the Florida manatees (Trichechus manatus latirostris) and all-year-round in their aquatic environment. Our objectives were to analyze the consequences of glyphosate exposure on their immune responses via T-lymphocyte proliferation assays and transcriptomics. We isolated peripheral blood mononuclear cells (mainly lymphocytes) of free-ranging manatees and performed T-cell proliferation assays. We used transcriptomics to understand the consequences of glyphosate in vitro exposure. The three doses chosen ranged from environmentally relevant concentrations at 10 to 10,000 µg.L−1 that is considered an environmental contamination scenario. Glyphosate caused a dose-dependent reduction in T-lymphocyte proliferation, with a significant mean reduction of 27.3 % at 10,000 µg.L−1 and up to 51.5 % in some individuals. Additionally, T-lymphocyte proliferation was significantly reduced in mid-winter compared to early winter. Transcriptomic analysis of peripheral blood mononuclear cells indicated that all doses of glyphosate (10, 1,000, and 10,000 µg.L−1) resulted in up-regulation of genes related to acute phase inflammation and inhibition of the T-lymphocyte proliferation pathway. Exposure to this contaminant along with other environmental stressors, such as extreme winters and red tide, might further affect the adaptive immune response of this threatened species.

Intracellular osteopontin potentiates the immunosuppressive activity of mesenchymal stromal cells

IntroductionMesenchymal stromal cell (MSC)-based cell therapy is a promising approach for various inflammatory disorders based on their immunosuppressive capacity. Osteopontin (OPN) regulates several cellular functions including tissue repair, bone metabolism and immune reaction. However, the biological function of OPN in regulating the immunosuppressive capacity of MSCs remains elusive.ObjectivesThis study aims to highlight the underlying mechanism of the proinflammatory cytokines affect the therapeutic ability of MSCs through OPN.MethodsMSCs in response to the proinflammatory cytokines were collected to determine the expression profile of OPN. In vitro T-cell proliferation assays and gene editing were performed to check the role and mechanisms of OPN in regulating the immunosuppressive capacity of MSCs. Inflammatory disease mouse models were established to evaluate the effect of OPN on improving MSC-based immunotherapy.ResultsWe observed that OPN, including its two isoforms iOPN and sOPN, was downregulated in MSCs upon proinflammatory cytokine stimulation. Interestingly, iOPN, but not sOPN, greatly enhanced the immunosuppressive activity of MSCs on T-cell proliferation and thus alleviated the inflammatory pathologies of hepatitis and colitis. Mechanistically, iOPN interacted with STAT1 and mediated its deubiquitination, thereby inducing the master immunosuppressive mediator inducible nitric oxide synthase (iNOS) in MSCs. In addition, iOPN expression was directly downregulated by activated STAT1, which formed a negative feedback loop to restrain MSC immunosuppressive capacity.ConclusionOur findings demonstrated that iOPN expression modulation in MSCs is a novel strategy to improve MSC-based immunotherapy.

Role of SARS-CoV-2-specific memory B cells promoting immune protection after booster vaccination in solid organ transplantation.

Solid organ transplant (SOT) recipients display weak seroconversion and neutralizing antibody (NAb) responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and remain at risk of severe coronavirus disease 2019 (COVID-19). While B-cell memory is the hallmark of serological immunity, its role in driving successful vaccine responses and providing immune protection in SOT patients remains unclear. We investigated the function and interplay of SARS-CoV-2-specific memory B cells (mBc), different cytokineproducing T cells, and cross-reactive NAb in driving seroconversion and protection against COVID-19 in two cohorts. First, we studied a large cohort of 148 SOT recipients and 32 immunocompetent individuals who underwent several vaccinations. Subsequently, we assessed 25 SOT patients participating in a randomized controlled trial to compare two different immunosuppressive strategies for allowing successful seroconversion and memory-cell responses after booster vaccination. We corroborate previous findings that B- and T-cell memory responses are weaker and more delayed in SOT patients than in immunocompetent (IC) individuals; however, within the SOT cohort, we found that these responses are relatively stronger and more robust in patients not receiving mycophenolate mofetil (MMF)-based therapies. Anti- spike IgG titers strongly correlated with RBD-specific IgG-producing mBc, with both displaying broad viral cross reactivity. Prebooster SARS-CoV-2-specific mBc and IL-2- producing T cells accurately predicted Nab seroconversion (AUC, 0.828) and protection against severe COVID-19. While switching unresponsive SOT patients from calcineurin inhibitors (CNI)/MMF to a low-exposure CNI/mTOR-i regimen favored wider SARS-CoV-2-specific immune responses after a fourth booster vaccination, preformed RBD-specific mBc predicted NAb seroconversion. Our study adds new insights into the pathobiology of immune memory and highlights the pivotal role of SARS-CoV-2-specific mBc in promoting immune protection inSOT patients.

Recurrent pancreatic cancer treated with N-803 and PD-L1 t-haNK followed by an EGFR-targeted nanocell drug conjugate.

Multimodal temporal therapy orchestrated to leverage immunotherapy, tumor-targeted chemotherapy, and natural killer (NK) cell therapy may provide an opportunity to induce immunogenic cell death for tumor response and increased survival in patients with recurrent cancer. The interleukin-15 (IL-15) superagonist N-803, an enhancer of NK cells, CD4 + T cells, cytotoxic CD8 + T cells, and memory T-cell activity, combined with off-the-shelf PD-L1-targeted high-affinity NK (PD-L1 t-haNK) cells represent novel immunotherapies designed to overcome an immunosuppressive tumor microenvironment (TME). The epidermal growth factor receptor-targeted antibody-nanocell conjugate E-EDV-D682 provides tumor-targeted chemotherapy in the form of its anthracycline metabolite PNU159682 (nemorubicin) cargo and is currently being studied in combination with immunomodulatory EDVs delivering the adjuvant α-galactosyl ceramide (GC). Here, we report the compassionate use treatment of this combination in a patient with recurrent, metastatic pancreatic cancer (mPC) after 3 lines of therapy. Under the initial single-patient Investigational New Drug (spIND) protocol, the patient received N-803, PD-L1 t-haNK cells, and the albumin doxorubicin conjugate aldoxorubicin for ~27 months. The patient's disease became stable on this regimen, and a transient complete response was observed by ~14 months of therapy. Due to progression, a second spIND protocol was designed whereby the patient received E-EDV-D682 plus EDV-GC for more than 24 months, which resulted in stable disease and the patient's continued survival at the time this report was written. The patient's extended survival despite the dire prognosis associated with recurrent mPC points to the merits of this temporal combination regimen in overcoming immuno-chemo resistance with enhanced immune activity required for tumor response and extended survival.

Biomimetic Single-Atom Nanozyme for Dual Starvation-Enhanced Breast Cancer Immunotherapy.

Cold exposure (CE) therapy is an innovative and cost-efficient cancer treatment that activates brown adipose tissue to compete for glucose uptake, leading to metabolic starvation in tumors. Exploring the combined antitumor mechanisms of CE and traditional therapies (such as nanocatalysis) is exciting and promising. In this study, a platelet membrane biomimetic single-atom nanozyme (SAEs) nanodrug (PFB) carrying bis-2-(5-phenylacetamido-1, 2, 4-thiadiazol-2-yl) ethyl sulfide (BPTES) is developed for use in cancer CE therapy. Owing to the platelet membrane modification, PFB can effectively target tumors. Upon entering cancer cells, the dual starvation effect induced by CE treatment and BPTES can significantly diminish intracellular glucose and ATP levels, resulting in a substantial reduction in cellular (glutathione) GSH, which can enhance the cytotoxic efficacy of reactive oxygen species generated by SAEs. This strategy not only boosts ROS production in tumors, but also strengthens immune responses, particularly by increasing memory T-cell abundance and suppressing distant tumor growth and tumor metastasis. Compared with SAEs therapy alone, this combined approach offers superior benefits for tumor immunotherapy. This study achieves a combination of CE and nanomedicines for the first time, providing new ideas for future nanomedicine combination therapy modalities.