T-cell Immune Responses Research Articles

The High-Resolution Structure Reveals Remarkable Similarity in PD-1 Binding of Cemiplimab and Dostarlimab, the FDA-Approved Antibodies for Cancer Immunotherapy.

Multiple tumors have responded well to immunotherapies, which use monoclonal antibodies to block the immune checkpoint proteins and reactivate the T-cell immune response to cancer cells. Significantly, the anti-PD-1 antibodies pembrolizumab and nivolumab, which were approved in 2014, have revolutionized cancer therapy, demonstrating dramatic improvement and longer duration. The US FDA authorized the third anti-PD-1 medication, cemiplimab, in 2018 for use in patients with cutaneous squamous cell carcinoma. To further understand the molecular mechanism of the antibody drug, we now reveal the intricate structure of PD-1 in complex with the cemiplimab Fab at a resolution of 1.98 Å. The cemiplimab-PD-1 interaction preoccupies the space for PD-L1 binding with a greater binding affinity than the PD-1/PD-L1 interaction, which is the basis for the PD-1 blocking mechanism. The structure reveals that cemiplimab and dostarlimab are significantly similar in PD-1 binding, although the precise interactions differ. A comparative investigation of PD-1 interactions with the four FDA-approved antibodies reveals that the BC, C'D, and FG loops of PD-1 adopt distinct conformations for optimal interaction with the antibodies. The structural characteristics in this work could be helpful information for developing more potent anti-PD-1 biologics against cancer.

Activated NK cells reprogram MDSCs via NKG2D-NKG2DL and IFN-γ to modulate antitumor T-cell response after cryo-thermal therapy

BackgroundMyeloid‐derived suppressor cells (MDSCs) can potently inhibit T-cell activity, promote growth and metastasis of tumor and contribute to resistance to immunotherapy. Targeting MDSCs to alleviate their protumor functions and immunosuppressive...

Across-cancer specific immune responses induced by nanovaccines or microvaccines to prevent different cancers and cancer metastasis.

Metastatic cancers and recurrent cancers are diverse, different from primary cancers, and organ-dependent. However, how strong are across-cancer immune responses among different types of cancers remain unclear. Herein, vaccines-encapsulated-whole-components-of-tumor-tissue (VEWCOTT) were applied to demonstrate the across-cancer immune responses, thanks to inducing pan-clones T-cell immune responses. Either lung-cancer-tissue- or melanoma-tissue-based VEWCOTT simultaneously prevented melanoma, lung cancer, hepatoma, and metastatic cancer, which showed that strong across-cancer immune responses were induced. Both nanovaccines and microvaccines showed potent across-cancer prevention efficacy. VEWCOTT induced tumor-specific Tcells in peripheral immune organs and major organs, and adjusted the immune-microenvironment of cancer-colonized organs. In addition, the allograft of Tcells from VEWCOTT immunized mice to allogeneic naive mice efficiently prevent various cancers. Many neoantigens are shared by melanoma cells and lung cancer cells. Across-cancer immune responses exist among different types of cancers, and thus VEWCOTT has the advantage of simultaneously preventing cancer metastasis and cancers in different organs.

Human amniotic fluid derived extracellular vesicles attenuate T cell immune response.

Extracellular vesicles isolated from human amniotic fluid (AF-EVs) have previously been found to modulate inflammation and macrophage infiltration in a mouse model. However, the effects of acellular amniotic fluid (acAF) or AF-EVs on the T-Cell immune response have not been explored. In this study, we investigated the effects of acAF and AF-EVs on the T cell immune response in an in vitro cell culture model. Peripheral Blood Mononuclear Cells (PBMCs) were stimulated with Phytohemagglutinin (PHA) to induce the immune response and were subsequently treated with either serum-free media (vehicle), acAF, or concentrated AF-EVs. Both acAF and AF-EV treatment suppressed PHA-induced T cell proliferation and PHA-induced T cell activation; however, treatment with concentrated AF-EVs had a greater effect. Additionally, both acAF and AF-EVs reduced PBMC pro-inflammatory cytokine release. AF-EVs were found to be taken up by both CD4+ and CD8+ effector T cell subsets. Overall, this data demonstrates that AF-EVs have a robust immunomodulatory effect on T cells and suggests AF-EVs could be used as an immunotherapeutic tool.

Autophagy-related 9 homolog B regulates T-cell-mediated immune responses in oral lichen planus

ObjectivesThis study aimed to explore the impacts of autophagy-related 9 homolog B (ATG9B)-mediated autophagy on T-cell immune responses in oral lichen planus. DesignATG9B expression was detected in lesions and local T cells by immunohistochemical analysis and immunofluorescence assay. The effects of ATG9B-mediated autophagy on T-cell immune responses were explored after ATG9B-overexpression or ATG9B-knockdown lentivirus transfection. A coculture system of activated T cells and lipopolysaccharide-induced keratinocytes was used to simulate the main cell crosstalk in oral lichen planus. ResultsThe expression of ATG9B upregulated in lesions and local T cells of oral lichen planus, especially in non-erosive oral lichen planus, suggesting that ATG9B may be a diagnostic factor for oral lichen planus. Notably, ATG9B-knockdown T cells of oral lichen planus demonstrated autophagy suppression, enhanced proliferation, and attenuated apoptosis, whereas overexpression of ATG9B showed opposite effects on T cells. In the coculture system of T cells and keratinocytes, ATG9B-knockdown T cells of oral lichen planus, but not ATG9B-overexpression T cells, promoted the proliferation and apoptosis of their cocultured keratinocytes. Additionally, exogenous insulin-like growth factor 1 (IGF1) significantly reversed the apoptosis rates of keratinocytes cocultured with T cells expressing abnormal ATG9B. Furthermore, ATG9B-overexpression T cells showed decreased secretion of interferon-γ and tumor necrosis factor-α in the coculture system. ConclusionsThis study revealed the regulatory roles of ATG9B-mediated T-cell autophagy on T-cell immune responses and crosstalk between T cells and keratinocytes in of oral lichen planus.

Factors Associated With Vaccine-Induced T-Cell Immune Responses Against Severe Acute Respiratory Syndrome Coronavirus 2 in Kidney Transplant Recipients.

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important prophylactic measure in kidney transplant recipients (KTRs), but the immune response is often impaired. Here, we examined the T-cell immune response against SARS-CoV-2 in 148 KTRs after 3 or 4 vaccine doses, including 35 KTRs with subsequent SARS-CoV-2 infection. The frequency of spike-specific T cells was lower in KTRs than in immunocompetent controls and was correlated with the level of spike-specific antibodies. Positive predictors for detection of vaccine-induced T cells were detection of spike-specific antibodies, heterologous immunization with messenger RNA and a vector vaccine, and longer time after transplantation. In vaccinated KTRs with subsequent SARS-CoV-2 infection, the T-cell response was greatly enhanced and was significantly higher than in vaccinated KTRs without SARS-CoV-2 infection. Overall, the data show a correlation between impaired humoral and T-cell immunity to SARS-CoV-2 vaccination and provide evidence for greater robustness of hybrid immunity in KTRs.

Regulation of piglet T-cell immune responses by thioredoxin peroxidase from Cysticercus cellulosae excretory-secretory antigens.

Taenia solium (T. solium) cysticercosis is a serious threat to human health and animal husbandry. During parasitization, Cysticercus cellulosae (C. cellulosae) can excrete and secrete antigens that modulate the host's T-cell immune responses. However, the composition of C. cellulosae excretory-secretory antigens (ESAs) is complex. This study sought to identify the key molecules in C. cellulosae ESAs involved in regulating T-cell immune responses. Thus, we screened for thioredoxin peroxidase (TPx), with the highest differential expression, as the key target by label-free quantification proteomics of C. cellulosae and its ESAs. In addition, we verified whether TPx protein mainly exists in C. cellulosae ESAs. The TPx recombinant protein was prepared by eukaryotic expression, and ESAs were used as the experimental group to further investigate the effect of TPx protein on the immune response of piglet T cells in vitro. TPx protein induced an increase in CD4+ T cells in piglet peripheral blood mononuclear cells (PBMCs), while CD8+ T cells did not change significantly. This resulted in an imbalance in the CD4+/CD8+ T-cell ratio and an increase in CD4+CD25+Foxp3+ Treg cells in the PBMCs. In addition, TPx protein initiated T helper 2 (Th2)-type immune responses by secreting IL-4 and IL-10 and suppressed Th1/Th17-type immune responses. The results showed that ESAs were involved in regulating piglet T-cell immune responses cells. This suggests that TPx protein found in ESAs plays an essential role to help the parasite evade host immune attack. Moreover, this lays a foundation for the subsequent exploration of the mechanism through which TPx protein regulates signaling molecules to influence T-cell differentiation.

Targeting arginase-1 exerts antitumor effects in multiple myeloma and mitigates bortezomib-induced cardiotoxicity

Multiple myeloma (MM) remains an incurable malignancy of plasma cells despite constantly evolving therapeutic approaches including various types of immunotherapy. Increased arginase activity has been associated with potent suppression of T-cell immune responses in different types of cancer. Here, we investigated the role of arginase 1 (ARG1) in Vκ*MYC model of MM in mice. ARG1 expression in myeloid cells correlated with tumor progression and was accompanied by a systemic drop in ʟ-arginine levels. In MM-bearing mice antigen-induced proliferation of adoptively transferred T-cells was strongly suppressed and T-cell proliferation was restored by pharmacological arginase inhibition. Progression of Vκ*MYC tumors was significantly delayed in mice with myeloid-specific ARG1 deletion. Arginase inhibition effectively inhibited tumor progression although it failed to augment anti-myeloma effects of bortezomib. However, arginase inhibitor completely prevented development of bortezomib-induced cardiotoxicity in mice. Altogether, these findings indicate that arginase inhibitors could be further tested as a complementary strategy in multiple myeloma to mitigate adverse cardiac events without compromising antitumor efficacy of proteasome inhibitors.

PAX5 Epigenetically Orchestrates CD58 Transcription and Modulates Blinatumomab Response in Acute Lymphoblastic Leukemia

Blinatumomab is a bi-specific molecule that engages CD3+ T cells with CD19-expressing malignant B cells, thus inducing tumor lysis by T-cell immune response. While large frontline ALL trials of blinatumomab are lacking, existing data strongly indicate substantial inter-patient variability in response and toxicities. Complete remission rate ranges from 36 to 66%, depending on the regimen used and patient characteristics. Moreover, the duration of remission varies among trials, with a significant proportion of patients experiencing relapse or progressive disease following blinatumomab treatment, raising concerns about acquired drug resistance. In particular, mechanisms of resistance in CD19+ relapse remain largely unclear. Using genome-wide CRISPR screen in B-ALL cell line in vitro, we comprehensively identified leukemia intrinsic factors of blinatumomab sensitivity. In addition to CD19 deletion the loss of CD58 emerged as a top driver for resistance, plausibly compromising the CD2-CD58-mediated interaction between T cells and B-ALL. Genomic editing of the CD58 gene or blocking with anti-CD58 antibody completely abrogated blinatumomab sensitivity across different B-ALL cell lines. Screening 1,639 transcription factor genes, we then identified PAX5 as the key activator of CD58. Interestingly, primary ALL samples with PAX5 P80R mutation also showed complete loss of CD58 expression, based on RNA-seq of 1,988 B-ALL samples across 20 molecular subtypes. To further validate this, we developed isogenic clones of the B-ALL cell line 697, with different PAX5 diplotypes: wildtype/wildtype (WT/WT), wildtype/frameshift (WT/fs), and P80R/frameshift (P80R/fs). P80R/fs and WT/fs clones exhibited significantly lower CD58 expression as compared to the WT/WT clone, and both were markedly resistant to blinatumomab. PAX5 mutation did not influence CD19 expression in these B-ALL cells. By testing a panel of primary ALL samples in vitro, we found that blast harboring the PAX5 P80R mutation has the lowest CD58 expression and was the most resistant to blinatumomab, which was reversed by ectopic expression of CD58. To delineate the mechanism by which PAX5 mutation affects CD58 suppression in ALL, we comprehensively profiled epigenomic marks within the CD58 locus in 697 cells with WT/fs, P80R/fs, and WT/WT genotypes. Using ChIP-seq, we identified PAX5 binding sites within Intron 1 of the CD58 genes. By contrast, PAX5 binding at this locus was decreased in WT/fs cells and completely eliminated in the P80R/fs clones, suggesting a loss-of-function effect of the P80R mutation. This region was also characterized by H3K27ac and H3K4me3 marks, signifying its enhancer activity, which was also lost in P80R/fs cells. ATAC-seq profiling of these samples showed a similar pattern of PAX5-dependent open chromatin status. CRISPR interference showed that blocking the genomic sequence encompassing this enhancer resulted in significant downregulation of CD58 expression. PAX5 binding was also observed in the CD19 promoter region, but P80R mutation had only modest effects on histone modification and chromatin accessibility at this locus. Finally, we explored the effects of CD58 loss on T cell activation. T cell cocultured with CD58KO Nalm6 clone showed a substantial decrease in activation and proliferation, as compared to that cocultured with parental Nalm6. Defects of activation and proliferation were also observed in T cells cocultured with PAX5 P80R/fs 697 clone as compared to those with parental 697. Using RNA-seq, we identified 111 genes that were highly expressed in T cells cocultured with parental (relative to those with CD58KO Nalm6). Among these hits, there was significant enrichment of genes involved in oxygen metabolisms, immune response, and cytokine signaling pathways, indicating the loss of CD58 abolished blinatumomab-induced T cell activation. ATAC-seq of these samples further confirmed the findings of RNA-seq studies. In conclusion, our study identified the critical role of CD58-mediated interaction between B-ALL and T cells for blinatumomab sensitivity in this type of leukemia, pointing to potential strategies for genomics-guided blinatumomab treatment individualization.

Metabolic Abnormalities Associated with T-Cell Exhaustion in CLL Eµ-TCL1 Murine Model

Introduction. T-cell differentiation and immune responses are associated with major metabolic changes that control cell fate upon antigen exposure. Chronic lymphocytic leukemia (CLL) is characterized by a marked T-cell dysfunction that plays a major role in disease progression and failure of adoptive cell therapy. A handful of recent studies have demonstrated mitochondrial and metabolic defects in the T-cell compartment in CLL patients. However, to date, no studies have been done to validate such metabolic abnormalities in the Eµ-TCL1 model, the most established and reliable murine model for studying CLL. Therefore, we hypothesized that CD8+ T-cells derived from the Eµ-TCL1 adoptive transfer model exhibit metabolic and mitochondrial disturbance that might contribute to the overall dysfunctional state of these cells. Methods. To investigate the influence of leukemic burden on the differentiation phenotypes, metabolic state and gene expression profile of CD8+ T-cells, C57BL/6 mice adoptively transferred with Eµ-TCL1 leukemic splenocytes were euthanized at varying time points. Once disease was established, spleens were collected for analysis. Mice were divided into 3 groups; early, intermediate, and late disease, based on the peripheral blood leukemic burden at endpoint. Multicolor flow cytometry was used for identification of T-cell phenotypes and measurement of mitochondrial mass, membrane potential, reactive oxygen species (ROS) and cellular glucose uptake. For T-cell activation studies, we cultured splenocytes in the presence of CD3/CD28 dynabeads and 30IU/ml hIL-2 for 72 hours. Nanostring metabolic pathways gene expression analysis was done on splenic CD8+ T-cells isolated from early and late-stage Eµ-TCL1 adoptive transfer mice via fluorescence-activated cell sorting. Differential gene expression was measured using ROSALIND cloud-based software platform. Results. Unsupervised t-distributed stochastic neighborhood embedding (tSNE) and Xshift clustering analyses revealed a gradual enrichment of specific CD8+ T-cell populations along disease progression. These populations upregulated exhaustion-related markers (EOMES, TOX, PD-1 and KLRG-1) and significantly downregulated TCF-1 expression, a transcription factor responsible for cell self-renewal capacity. Further analysis demonstrated a significant downregulation of PGC-1α expression, a master regulator of mitochondrial function, in Eµ-TCL1 CD8+ T-cells with high EOMES and low TCF-1 expression levels (EOMEShi TCF-1lo) compared to EOMEShi TCF-1hi cells. At late disease stage, we noticed significant mitochondrial depolarization, an increase in mitochondrial ROS and marked reduction in glucose uptake capacity in the Eµ-TCL1 CD8+ T-cells. Post in vitro activation, there was a significant increase in Eµ-TCL1 CD8+ T-cell mitochondrial biogenesis, membrane potential and ROS production compared to wild type (WT) controls. However, Eµ-TCL1 cultures showed significant enrichment in EOMEShi TCF-1lo CD8+ T-cell population, that was not detected in the activated WT cells. Interestingly, this population exhibited marked downregulation of PGC-1α, SOD-2 and NRF-2 expression compared to the populations maintaining TCF-1 expression. Moreover, we found that Eµ-TCL1 CD8+ T-cells had increased frequency of effector memory phenotypes compared to more central memory cells in WT cultures. These effector memory populations accumulated significant levels of mitochondrial ROS and depolarized mitochondria compared to the central memory counterparts. Nanostring analysis revealed disease stage-dependent changes in gene expression, where glycolysis was the top differentially expressed pathway in the late versus early-stage CD8+ T-cells as indicated by the gene set global significance score. On the other hand, negative significance scores were assigned to AMPK and autophagy pathways indicating a probable downregulation of these pathways during late phases of the disease. Conclusion. Our results demonstrate mitochondrial and metabolic abnormalities in Eµ-TCL1-derived CD8+ T-cells and point to possible defects in cellular stress signaling response that might lead to accumulation of dysfunctional mitochondria and push the cells towards exhausted states.

Humoral and cellular response to the COVID-19 vaccine in immunocompromised children.

A suboptimal response to the 2-dose COVID-19 vaccine series in the immunocompromised population prompted recommendations for a 3rd primary dose. We aimed to determine the humoral and cellular immune response to the 3rd COVID-19 vaccine in immunocompromised children. Prospective cohort study of immunocompromised participants, 5-21 years old, who received 2 prior doses of an mRNA COVID-19 vaccine. Humoral and CD4/CD8 T-cell responses were measured to SARS-CoV-2 spike antigens prior to receiving the 3rd vaccine dose and 3-4 weeks after the 3rd dose was given. Of the 37 participants, approximately half were solid organ transplant recipients. The majority (86.5%) had a detectable humoral response after the 2nd and 3rd vaccine doses, with a significant increase in antibody levels after the 3rd dose. Positive T-cell responses increased from being present in 86.5% to 100% of the cohort after the 3rd dose. Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This supports the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in this population. Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This is the first prospective cohort study to analyze both the humoral and T-cell immune response to the 3rd COVID-19 primary vaccine dose in children who are immunocompromised. The results of this study support the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in the immunosuppressed pediatric population.

Clinical Outcomes, Immunogenicity, and Safety of BNT162b2 Vaccine in Primary Antibody Deficiency

Common variable immunodeficiency (CVID) is characterized by an impaired postvaccination response, high susceptibility to respiratory tract infections, and a broad spectrum of noninfectious complications. Thus, patients with CVID may be at high risk for COVID-19, and vaccination's role in prevention is questionable. We evaluated the clinical outcomes, safety, and dynamics of humoral and T-cell immune responses induced by the mRNA vaccine BNT162b2 in CVID. This prospective observational cohort study focused on the clinical outcomes (proportion of infected patients and disease severity), safety (incidences of adverse events and changes in laboratory parameters), and dynamics of humoral (specific postvaccination and virus-neutralizing antibody assessment) and T-cell immune responses (anti-SARS-CoV-2-specific T-cell detection) in 21 patients with CVID after a two-dose administration of BNT162b2. The patients were observed for 6 months. Humoral response was observed in 52% of patients (11 of 21) at month 1 after vaccination but continuously decreased to 33.3% at month 6 (five of 15). Nevertheless, they had a remarkably lower anti-SARS-CoV-2 neutralizing antibody titer compared with healthy controls. The T-cell response was measurable in 46% of patients with CVID (six of 13) at month 1 and persisted over the study period. Mild infection occurred in three patients within the follow-up period (14.3%). The vaccine also exhibited a favorable safety profile. The BNT162b2 vaccine elicited a measurable antibody response in a high proportion of patients, but it was limited by low titer of virus-neutralizing antibodies and rapid waning of anti-receptor-binding domain SARS-CoV-2-specific antibodies. T-cell response was detected in one-third of patients and remained stable within the follow-up period. Vaccination has favorable safety and clinical-related outcomes in preventing severe COVID-19.

Mycobacterium tuberculosis: Implications of Ageing on Infection and Maintaining Protection in the Elderly.

Several reports have suggested that ageing negatively affects the human body resulting in the alteration of various parameters important for sufficient immune health. Although, the breakdown of innate and adaptive immunity has been hypothesized to increase an individual's susceptibility to infections including Mycobacteria tuberculosis (M. tb), little research has been done to bridge this gap and understand the pathophysiology underlying how ageing increases the pathogenesis of M. tb infection. Our objective was to study research from a plethora of resources to better understand the pathogenesis of ageing and its link to the human immune system. To achieve this goal, this article explores how ageing decreases the collective T-cell immune response, reduces glutathione (GSH) production, over activates the mammalian target of rapamycin (mTORC1) pathway, inhibits autophagy and mitophagy, and alters various protective genes/transcription factors. Specifically highlighting how each of these pathways cripple an individual's immune system and increases their susceptibility from M. tb infection. Furthermore, research summarized in this article gives rise to an additional mechanism of susceptibility to M. tb infection which includes a potential defect in antigen presenting by dendritic cells rather than the T-cells response. Inflammaging has also been shown to play a role in the ageing of the immune system and can also potentially be a driving factor for increased susceptibility to M. tb infection in the elderly. In addition, this article features possible preventative strategies that could decrease infections like M. tb in this population. These strategies would need to be further explored and range from immunomodulators, like Everolimus to antioxidant supplementation through GSH intake. We have also proposed the need to research these therapies in conjunction with the administration of the BCG vaccine, especially in endemic populations, to better understand the risk contracting M. tb infection as well as ways to prevent infection in the first place.

Optimizing tuberculosis screening for immigrants in southern New Brunswick: A pilot study protocol.

Immigrants from high tuberculosis-burdened countries have been shown to have an increased risk of latent tuberculosis infection (LTBI). To reduce the risk of increased tuberculosis cases in Canada, the country has a comprehensive immigration medical examination process that identifies individuals with active tuberculosis using chest X-ray; however, it fails to identify LTBI. The lack of LTBI identification is concerning because immigrants with LTBI are at an increased risk of developing active tuberculosis within their first few years of migration due to stressful experiences common to many immigrants. The goal of this pilot study is to improve the current LTBI screening protocols among immigrants from high tuberculosis incidence countries and to better prevent and manage tuberculosis cases, by introducing an LTBI screening pilot program. The objectives are threefold: 1) to screen LTBI in immigrants from high tuberculosis incidence countries, including immigrants identified as being at risk of LTBI by the NB health care system, using the QuantiFERON-TB Gold Plus interferon-gamma release assay (IGRA); 2) to offer LTBI treatment and supports to those identified as having LTBI; and 3) to assess immigrant and health care providers (HCPs) satisfaction of the LTBI screening pilot program. This cross-sectional study seeks to recruit 288 participants. Participants will be recruited via posters, social media platforms, invitations at immigrant wellness check-ups, presentations to local ethnocultural groups, and by snowball sampling. Consenting participants will be asked to submit a blood sample for LTBI screening; if positive, participants will be assessed and offered treatment for LTBI based on clinical assessment. Participants and HCPs' feedback will be gathered via short questionnaires. For the quantitative portion of the study, descriptive statistics will be used to summarize participant characteristics and feedback. Simultaneous logistic regression will be performed to identify variables associated with the IGRA test outcome and evidence of increased CD8 T-cell immune response among those found to be LTBI-positive. Qualitative results will be analyzed using inductive thematic analysis. The findings from this study will allow us to understand the role of the IGRA LTBI screening assay and its feasibility and acceptability by immigrants and HCPs in New Brunswick. The findings will additionally provide information on the enhancers and barriers of LTBI screening and management useful in determining how best to expand the LTBI screening program if deemed appropriate.

Adipose-derived stem cells regulate CD4+ T-cell-mediated macrophage polarization and fibrosis in fat grafting in a mouse model

Autologous fat grafting is becoming increasingly common worldly. However, the long-term retention of fat grafting is still unpredictable due to the inevitable fibrosis arising during tissue repair. Fibrosis may be regulated by T-cell immune responses that are influenced by adipose-derived stem cells (ASCs). Therefore, we hypothesized that overly abundant ASCs might promote fibrosis by promoting T-cell immune responses to adipose tissue. We performed 0.3 ml fat grafts with 104/ml, 106/ml and 108/ml ASCs and control group in C57 BL/6 mice in vivo. We observed retention, fibrosis, T-cell immunity, and macrophage infiltration over 12 weeks. Besides, CD4+ T-helper 1 (Th1) cells and T-helper 2 (Th2) cells were co-cultured with ASCs or ASCs conditioned media (ASCs-CM) in vitro. We detected the ratio of Th2%/Th1%. Results showed that the retention rate was higher in 104 group, while even lower in 108 group with significantly increased inflammation and fibrosis than control group at week 12 in vivo. There was no significance between control group and 106 group. Also, 108 group increased the infiltration of M2 macrophages, CD4+ T-cells and Th2/Th1 ratio. In vitro, the ratio of Th2%/Th1% induced by ASCs-transwell group was higher than ASCs-CM group and showed concentration-dependent. Accordingly, high concentrations of ASCs in adipose tissue can promote Th1–Th2 shifting, and excessive Th2 cells might promote the persistence of M2 macrophages and increase the level of fibrosis which lead to a decrease in the long-term retention of fat grafts. Also, we found ASCs promoted Th1–Th2 shifting in vitro.

Tumor Antigen Loaded Nanovaccine Induced NIR-Activated Inflammation for Enhanced Antigen Presentation During Immunotherapy of Tumors.

Although anticancer vaccines have achieved certain effects in early clinical practice, T cell immunity as the most common responsive pattern of anticancer vaccines is still limited by unsatisfied tumor recognition and inhibition efficiency. As the critical step of T cell immunity, uptake and presentation of specific antigen by antigen-presenting cells (APC) can be activated by inflammation for enhancing the response of T cells to the antigen source. Here, a hybrid nanovaccine named PTh/MnO2 @M activated with a near-infrared ray (NIR) is prepared by coating an autologous tumor cell membrane on the surface of a polythiophene/MnO2 composite core. The photoelectrical material polythiophene can produce local microinflammation under NIR radiation and activate specific T cell antitumor immunity by promoting APC maturation and autologous tumor antigens presentation. Moreover, the synthesized nanovaccine PTh/MnO2 @M is shown to induce a significant antitumor immune response, effectively inhibit the progression of melanoma in mice, and significantly prolong the survival time of mice in vivo. This strategy aims to enhance T-cell immune responses by promoting antigen presentation, leading to effective and specific cancer therapy.

CRISPR/Cas9-mediated gene knockout of Sj16 in Schistosoma japonicum eggs upregulates the host-to-egg immune response.

Schistosomiasis is an important, neglected tropical disease. Schistosoma japonicum can evade host attacks by regulating the host's immunity, causing continuous infection. However, interactions between the host's immune system and S. japonicum are unclear. Our previous research found that the Sj16 protein isolated from S. japonicum has an anti-inflammatory effect in the host. However, the role of Sj16 in the regulation of host immunity in S. japonicum infection is not clear. Here, we applied the CRISPR/Cas9 technique to knockout Sj16 in S. japonicum eggs and investigated the effect of Sj16 in regulating host immunity. We found egg viability decreased after Sj16 knockout. In addition, we found granulomatous inflammation increased, the T-cell immune response enhanced and the immune microenvironment changed in mice model injected with Sj16-knockout eggs by tail vein. These findings suggested that S. japonicum could regulate host immunity through Sj16 to evade the host immune attack and cause continuous infection. In addition, we confirmed the application of CRISPR/Cas9-mediated gene reprogramming for functional genomics in S. japonicum.

Neutralizing antibodies and T-cell responses to inactivated SARS-CoV-2 vaccine in COVID-19 convalescents one and a half years after infection

Vaccines have been considered the most promising solution for ending the coronavirus disease 2019 (COVID-19) pandemic. Information regarding neutralizing antibodies (NAbs) and T-cell immune response in inactivated SARS-CoV-2 vaccine-immunized COVID-19 convalescent patients were either only available for a short time after illness recovered or not available at all (T-cell immunity). We evaluated SARS-CoV-2 NAbs and cellular immune responses to the SARS-CoV-2 inactivated vaccine in convalescent patients who recovered from infection for about one and a half years. We found that compared to before vaccination, SARS-CoV-2 NAbs and specific T-cell responses were significantly boosted by the inactivated vaccine in convalescent patients, which confirmed the pre-existing adaptive immunity in SARS-CoV-2 infected people. We observed that NAbs and IFN-γ-secreting T-cell response elicited by a single vaccine dose in subjects with prior COVID-19 infection were higher than after two doses of vaccine in SARS-CoV-2 naïve subjects. Both humoral and cellular immune responses elicited by one and two doses of inactivated vaccine were comparable in COVID-19-recovered persons. In conclusion, inactivated COVID-19 vaccine induced robust NAbs and T-cell responses to SARS-CoV-2 in COVID-19 convalescent patients and immune responses after one dose were equal to that after receiving two doses, which highlighted that robust humoral and cellular immune response can be reactivated by the inactivated vaccine in SARS-CoV-2 convalescent patients.

The pleiotropic roles of EZH2 in T-cell immunity and immunotherapy.

EZH2 is a histone methyltransferase. It catalyzes trimethylation of histone H3 at lysine 27 (H3K27me3) to control gene transcription critical for cell proliferation, differentiation, expansion, and function. For instance, EZH2 plays a central role in regulating T-cell immune responses. EZH2 restrains terminal differentiation of effector CD8 T cells, promotes formation of precursor and mature memory CD8 T cells, regulates appropriate lineage-specification and identity maintenance of helper CD4 T cells, and maintains survival of differentiated antigen-specific T cells. Most importantly, EZH2 is shown to be important for reinvigoration of exhausted chimeric antigen receptor (CAR) T cells. Dysregulated EZH2 function has been linked to many forms of cancer, including lymphomas and solid tumors. In B-cell lymphoid malignancies, EZH2 is overexpressed to drive tumorigenesis. These specific effects of EZH2, in the context of its roles in catalyzing H3K27me3 and orchestrating gene transcription programs in both normal and malignant cells, establishes EZH2 as a unique target for drug development. Here, we will discuss Ezh2 regulation of T-cell immunity, EZH2-mediated lymphomagenesis, and therapeutic benefits of EZH2 inhibitors to the treatment of lymphoma.

VSTM5 is a novel immune checkpoint that promotes oral tolerance of cell-mediated and antibody responses

The V-set and transmembrane domain-containing protein (VSTM) family is a newly discovered immunoglobulin (Ig) superfamily that shares structural similarities with the B7-like transmembrane proteins. Although most VSTM5 members have been reported to exert immune-related functions, VSTM5 has been described as a regulator of neuronal morphogenesis and migration in the brain. Based on its close phylogenetic relationship with two immune checkpoints, VISTA and TIGIT, we investigated the potential role of VSTM5 in T-cell immune responses. VSTM5.Ig inhibits T-cell proliferation and cytokine production, induces T-cell apoptosis, and promotes the generation of regulatory T cells (Tregs) in in vitro T-cell assays. VSTM5 also contributes to the maintenance of T-cell anergy in vitro. Similarly, serum VSTM5.Ig produced using a recombinant plasmid in ovalbumin (OVA)-immunized mice inhibits both naive and effector T-cell immune responses. In addition, VSTM5.Ig enhances oral tolerance of cell-mediated and antibody responses in OVA-fed mice by inducing Tregs and T-cell clonal deletion. Consequently, our findings suggest that VSTM5 is a novel immune checkpoint that could be used to improve the therapeutic efficacy of tolerance-based therapies for autoimmune diseases.