KSHV infection of B cells primes protective T cell responses in humanized mice.

Kaposi sarcoma associated herpesvirus (KSHV) is associated with around 1% of all human tumors, including the B cell malignancy primary effusion lymphoma (PEL), in which co-infection with the Epstein Barr virus (EBV) can almost always be found in malignant cells. Here, we demonstrate that KSHV/EBV co-infection of mice with reconstituted human immune systems (humanized mice) leads to IgM responses against both latent and lytic KSHV antigens, and expansion of central and effector memory CD4+ and CD8+ T cells. Among these, KSHV/EBV dual-infection allows for the priming of CD8+ T cells that are specific for the lytic KSHV antigen K6 and able to kill KSHV/EBV infected B cells. This suggests that K6 may represent a vaccine antigen for the control of KSHV and its associated pathologies in high seroprevalence regions, such as Sub-Saharan Africa.

Calcineurin inhibition rescues alloantigen-specific central memory T cell subsets that promote chronic GVHD.

Calcineurin inhibitors (CNIs) constitute the backbone of modern acute graft-versus-host disease (aGVHD) prophylaxis regimens but have limited efficacy in the prevention and treatment of chronic GVHD (cGVHD). We investigated the effect of CNIs on immune tolerance after stem cell transplantation with discovery-based single-cell gene expression and T cell receptor (TCR) assays of clonal immunity in tandem with traditional protein-based approaches and preclinical modeling. While cyclosporin and tacrolimus suppressed the clonal expansion of CD8+ T cells during GVHD, alloreactive CD4+ T cell clusters were preferentially expanded. Moreover, CNIs mediated reversible dose-dependent suppression of T cell activation and all stages of donor T cell exhaustion. Critically, CNIs promoted the expansion of both polyclonal and TCR-specific alloreactive central memory CD4+ T cells (TCM) with high self-renewal capacity that mediated cGVHD following drug withdrawal. In contrast to posttransplant cyclophosphamide (PT-Cy), CSA was ineffective in eliminating IL-17A-secreting alloreactive T cell clones that play an important role in the pathogenesis of cGVHD. Collectively, we have shown that, although CNIs attenuate aGVHD, they paradoxically rescue alloantigen-specific TCM, especially within the CD4+ compartment in lymphoid and GVHD target tissues, thus predisposing patients to cGVHD. These data provide further evidence to caution against CNI-based immune suppression without concurrent approaches that eliminate alloreactive T cell clones.

Urine scRNAseq reveals new insights into the bladder tumor immune microenvironment.

Due to bladder tumors' contact with urine, urine-derived cells (UDCs) may serve as a surrogate for monitoring the tumor microenvironment (TME) in bladder cancer (BC). However, the composition of UDCs and the extent to which they mirror the tumor remain poorly characterized. We generated the first single-cell RNA-sequencing of BC patient UDCs with matched tumor and peripheral blood mononuclear cells (PBMC). BC urine was more cellular than healthy donor (HD) urine, containing multiple immune populations including myeloid cells, CD4+ and CD8+ T cells, natural killer (NK) cells, B cells, and dendritic cells (DCs) in addition to tumor and stromal cells. Immune UDCs were transcriptionally more similar to tumor than blood. UDCs encompassed cytotoxic and activated CD4+ T cells, exhausted and tissue-resident memory CD8+ T cells, macrophages, germinal-center-like B cells, tissue-resident and adaptive NK cells, and regulatory DCs found in tumor but lacking or absent in blood. Our findings suggest BC UDCs may be surrogates for the TME and serve as therapeutic biomarkers.

Human T-cell activation with Toxoplasma gondii antigens loaded in maltodextrin nanoparticles.

Toxoplasmosis is the most prevalent parasitic zoonosis worldwide, causing ocular and neurological diseases. No vaccine has been approved for human use. We evaluated the response of peripheral blood mononuclear cells (PBMCs) to a novel construct of Toxoplasma gondii total antigen in maltodextrin nanoparticles (NP/TE) in individuals with varying infectious statuses (uninfected, chronic asymptomatic, or ocular toxoplasmosis). We analyzed the concentration of IFN-γ after NP/TE ex vivo stimulation using ELISA and the immunophenotypes of CD4+ and CD8+ cell populations using flow cytometry. In addition, serotyping of individuals with toxoplasmosis was performed by ELISA using GRA6-derived polypeptides. Low doses of NP/TE stimulation (0.9 µg NP/0.3 µg TE) achieved IFN-γ-specific production in previously exposed human PBMCs without significant differences in the infecting serotype. Increased IFN-γ expression in CD4+ effector memory cell subsets was found in patients with ocular toxoplasmosis with NP/TE but not with TE alone. This is the first study to show how T-cell subsets respond to ex vivo stimulation with a vaccine candidate for human toxoplasmosis, providing crucial insights for future clinical trials.

[Immune Regulation by TNF Receptor-associated Factor 5].

The tumor necrosis factor receptor (TNFR)-associated factor (TRAF) family of molecules are intracellular adaptors that regulate cellular signaling through members of the TNFR and Toll-like receptor superfamily. Mammals have seven TRAF molecules numbered sequentially from TRAF1 to TRAF7. Although TRAF5 was identified as a potential regulator of TNFR superfamily members, the in vivo function of TRAF5 has not yet been fully elucidated. We identified an unconventional role of TRAF5 in interleukin-6 (IL-6) receptor signaling involving CD4+ T cells. Moreover, TRAF5 binds to the signal-transducing glycoprotein 130 (gp130) receptor for IL-6 and inhibits the activity of the janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway. In addition, Traf5-deficient CD4+ T cells exhibit significantly enhanced IL-6-driven differentiation of T helper 17 (Th17) cells, which exacerbates neuroinflammation in experimental autoimmune encephalomyelitis. Furthermore, TRAF5 demonstrates a similar activity to gp130 for IL-27, another cytokine of the IL-6 family. Additionally, Traf5-deficient CD4+ T cells display significantly increased IL-27-mediated differentiation of Th1 cells, which increases footpad swelling in delayed-type hypersensitivity response. Thus, TRAF5 functions as a negative regulator of gp130 in CD4+ T cells. This review aimed to explain how TRAF5 controls the differentiation of CD4+ T cells and discuss how the expression of TRAF5 in T cells and other cell types can influence the development and progression of autoimmune and inflammatory diseases.

Persistent T cell unresponsiveness associated with chronic visceral leishmaniasis in HIV-coinfected patients.

A large proportion of HIV-coinfected visceral leishmaniasis (VL-HIV) patients exhibit chronic disease with frequent VL recurrence. However, knowledge on immunological determinants underlying the disease course is scarce. We longitudinally profiled the circulatory cellular immunity of an Ethiopian HIV cohort that included VL developers. We show that chronic VL-HIV patients exhibit high and persistent levels of TIGIT and PD-1 on CD8+/CD8- T cells, in addition to a lower frequency of IFN-γ+ TIGIT- CD8+/CD8- T cells, suggestive of impaired T cell functionality. At single T cell transcriptome and clonal resolution, the patients show CD4+ T cell anergy, characterised by a lack of T cell activation and lymphoproliferative response. These findings suggest that PD-1 and TIGIT play a pivotal role in VL-HIV chronicity, and may be further explored for patient risk stratification. Our findings provide a strong rationale for adjunctive immunotherapy for the treatment of chronic VL-HIV patients to break the recurrent disease cycle.

Bystander Effects and Profibrotic Interactions in Hepatic Stellate Cells during HIV and HCV Coinfection.

This study aims to explore the influence of coinfection with HCV and HIV on hepatic fibrosis. A coculture system was set up to actively replicate both viruses, incorporating CD4 T lymphocytes (Jurkat), hepatic stellate cells (LX-2), and hepatocytes (Huh7.5). LX-2 cells' susceptibility to HIV infection was assessed through measurements of HIV receptor expression, exposure to cell-free virus, and cell-to-cell contact with HIV-infected Jurkat cells. The study evaluated profibrotic parameters, including programed cell death, ROS imbalance, cytokines (IL-6, TGF-ß, and TNF-α), and extracellular matrix components (collagen, α-SMA, and MMP-9). The impact of HCV infection on LX-2/HIV-Jurkat was examined using soluble factors released from HCV-infected hepatocytes. Despite LX-2 cells being nonsusceptible to direct HIV infection, bystander effects were observed, leading to increased oxidative stress and dysregulated profibrotic cytokine release. Coculture with HIV-infected Jurkat cells intensified hepatic fibrosis, redox imbalance, expression of profibrotic cytokines, and extracellular matrix production. Conversely, HCV-infected Huh7.5 cells exhibited elevated profibrotic gene transcriptions but without measurable effects on the LX-2/HIV-Jurkat coculture. This study highlights how HIV-infected lymphocytes worsen hepatic fibrosis during HCV/HIV coinfection. They increase oxidative stress, profibrotic cytokine levels, and extracellular matrix production in hepatic stellate cells through direct contact and soluble factors. These insights offer valuable potential therapies for coinfected individuals.

Inhibition of caspase pathways limits CD4+ T cell loss and restores host anti-retroviral function in HIV-1 infected humanized mice with augmented lymphoid tissue.

The study of HIV infection and pathogenicity in physical reservoirs requires a biologically relevant model. The human immune system (HIS) mouse is an established model of HIV infection, but defects in immune tissue reconstitution remain a challenge for examining pathology in tissues. We utilized exogenous injection of the human recombinant FMS-like tyrosine kinase 3 ligand (rFLT-3 L) into the hematopoietic stem cell (HSC) cord blood HIS mouse model to significantly expand the total area of lymph node (LN) and the number of circulating human T cells. The results enabled visualization and quantification of HIV infectivity, CD4 T cell depletion and other measures of pathogenesis in the secondary lymphoid tissues of the spleen and LN. Treatment with the Caspase-1/4 inhibitor VX-765 limited CD4+ T cell loss in the spleen and reduced viral load in both the spleen and axillary LN. In situ hybridization further demonstrated a decrease in viral RNA in both the spleen and LN. Transcriptomic analysis revealed that in vivo inhibition of caspase-1/4 led to an upregulation in host HIV restriction factors including SAMHD1 and APOBEC3A. These findings highlight the use of rFLT-3 L to augment human immune system characteristics in HIS mice to support investigations of HIV pathogenesis and test host directed therapies, though further refinements are needed to further augment LN architecture and cellular populations. The results further provide in vivo evidence of the potential to target inflammasome pathways as an avenue of host-directed therapy to limit immune dysfunction and virus replication in tissue compartments of HIV+ persons.

Tracking in situ checkpoint inhibitor-bound target T cells in patients with checkpoint-induced colitis.

The success of checkpoint inhibitors (CPIs) for cancer has been tempered by immune-related adverse effects including colitis. CPI-induced colitis is hallmarked by expansion of resident mucosal IFNγ cytotoxic CD8+ T cells, but how these arise is unclear. Here, we track CPI-bound T cells in intestinal tissue using multimodal single-cell and subcellular spatial transcriptomics (ST). Target occupancy was increased in inflamed tissue, with drug-bound T cells located in distinct microdomains distinguished by specific intercellular signaling and transcriptional gradients. CPI-bound cells were largely CD4+ T cells, including enrichment in CPI-bound peripheral helper, follicular helper, and regulatory T cells. IFNγ CD8+ T cells emerged from both tissue-resident memory (TRM) and peripheral populations, displayed more restricted target occupancy profiles, and co-localized with damaged epithelial microdomains lacking effective regulatory cues. Our multimodal analysis identifies causal pathways and constitutes a resource to inform novel preventive strategies.

Probiotic-derived amphiphilic exopolysaccharide self-assembling adjuvant delivery platform for enhancing immune responses.

Enhancing immune response activation through the synergy of effective antigen delivery and immune enhancement using natural, biodegradable materials with immune-adjuvant capabilities is challenging. Here, we present NAPSL.p that can activate the Toll-like receptor 4 (TLR4) pathway, an amphiphilic exopolysaccharide, as a potential self-assembly adjuvant delivery platform. Its molecular structure and unique properties exhibited remarkable self-assembly, forming a homogeneous nanovaccine with ovalbumin (OVA) as the model antigen. When used as an adjuvant, NAPSL.p significantly increased OVA uptake by dendritic cells. In vivo imaging revealed prolonged pharmacokinetics of NAPSL. p-delivered OVA compared to OVA alone. Notably, NAPSL.p induced elevated levels of specific serum IgG and isotype titers, enhancing rejection of B16-OVA melanoma xenografts in vaccinated mice. Additionally, NAPSL.p formulation improved therapeutic effects, inhibiting tumor growth, and increasing animal survival rates. The nanovaccine elicited CD4+ and CD8+ T cell-based immune responses, demonstrating the potential for melanoma prevention. Furthermore, NAPSL.p-based vaccination showed stronger protective effects against influenza compared to Al (OH)3 adjuvant. Our findings suggest NAPSL.p as a promising, natural self-adjuvanting delivery platform to enhance vaccine design across applications.

HIV immunological non-responders are characterized by extensive immunosenescence and impaired lymphocyte cytokine production capacity.

Introduction: Immunological non-responders (INR) are people living with HIV (PLHIV) who fail to fully restore CD4+ T-cell counts despite complete viral suppression with antiretroviral therapy (ART). INR are at higher risk for non-HIV related morbidity and mortality. Previous research suggest persistent qualitative defects. Methods: The 2000HIV study (clinical trials NTC03994835) enrolled 1895 PLHIV, divided in a discovery and validation cohort. PLHIV with CD4 T-cell count <350 cells/mm3 after ≥2 years of suppressive ART were defined as INR and were compared to immunological responders (IR) with CD4 T-cell count >500 cells/mm3. Logistic and rank based regression were used to analyze clinical data, extensive innate and adaptive immunophenotyping, and ex vivo monocyte and lymphocyte cytokine production after stimulation with various stimuli. Results: The discovery cohort consisted of 62 INR and 1224 IR, the validation cohort of 26 INR and 243 IR. INR were older, had more advanced HIV disease before starting ART and had more frequently a history of non-AIDS related malignancy. INR had lower absolute CD4+ T-cell numbers in all subsets. Activated (HLA-DR+, CD38+) and exhausted (PD1+) subpopulations were proportionally increased in CD4 T-cells. Monocyte and granulocyte immunophenotypes were comparable. INR lymphocytes produced less IL-22, IFN-γ, IL-10 and IL-17 to stimuli. In contrast, monocyte cytokine production did not differ. The proportions of CD4+CD38+HLA-DR+ and CD4+PD1+ subpopulations showed an inversed correlation to lymphocyte cytokine production. Conclusions: INR compared to IR have hyperactivated and exhausted CD4+ T-cells in combination with lymphocyte functional impairment, while innate immune responses were comparable. Our data provide a rationale to consider the use of anti-PD1 therapy in INR.

Herpesvirus Entry Mediator as an Immune Checkpoint Target and a Potential Prognostic Biomarker in Myeloid and Lymphoid Leukemia.

Herpesvirus entry mediator (HVEM) is a molecular switch that can modulate immune responses against cancer. The significance of HVEM as an immune checkpoint target and a potential prognostic biomarker in malignancies is still controversial. This study aims to determine whether HVEM is an immune checkpoint target with inhibitory effects on anti-tumor CD4+ T cell responses in vitro and whether HVEM gene expression is dysregulated in patients with acute lymphocytic leukemia (ALL). HVEM gene expression in tumor cell lines and peripheral blood mononuclear cells (PBMCs) from ALL patients and healthy controls was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor cells were left untreated (control) or were treated with an HVEM blocker before co-culturing with CD4+ T cells in vitro in a carboxyfluorescein succinimidyl ester (CFSE)-dependent proliferation assay. HVEM expression was upregulated in the chronic myelogenous leukemia cell line (K562) (FC = 376.3, p = 0.086) compared with normal embryonic kidney cells (Hek293). CD4+ T cell proliferation was significantly increased in the HVEM blocker-treated K562 cells (p = 0.0033). Significant HVEM differences were detected in ALL PBMCs compared with the controls, and these were associated with newly diagnosed ALL (p = 0.0011) and relapsed/refractory (p = 0.0051) B cell ALL (p = 0.0039) patients. A significant differentiation between malignant ALL and the controls was observed in a receiver operating characteristic (ROC) curve analysis with AUC = 0.78 ± 0.092 (p = 0.014). These results indicate that HVEM is an inhibitory molecule that may serve as a target for immunotherapy and a potential ALL biomarker.

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vß21.3+ activation in multi-inflammatory syndrome in children.

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vß21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vß21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vß21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.

Response to Neoadjuvant Chemotherapy in Invasive Breast Cancer Predicted by CD4+, CD8+, and FOXP3+ Tumor-Infiltrating Lymphocytes.

BACKGROUND: Response to neoadjuvant chemotherapy (NC) in individuals with invasive breast cancer (IBC) must be monitored, and biomarkers are needed. NC can activate an anti-tumour immune response in its microenvironment, known as Tumor-infiltrating Lymphocytes (TIL). TIL components believed to have great potential as predictors are CD4+, CD8+, and FOXP3+ TIL. This study aims to explore TIL components that can potentially be predictive biomarkers of NC pathological responses. METHODS: A sample size of 40 were analyzed based on the relationship between CD4+, CD8+, and FOXP3+ TIL expression with the Miller-Payne (MP) grading system. Age, tumour grade, PR, ER, Ki-67, and HER2 were also evaluated. CD4+, CD8+, and FOXP3+ TIL expressions were analayzed by IHC staining, while other data were collected from archives. Data was analyzed using univariate and multivariate analysis. RESULTS: Univariate analysis showed a significant relationship between CD4+ TIL and MP (p<0.001), CD8+ and MP (p=0.004), and FOXP3 with MP (p<0.001). The simultaneous integration of the three biomarkers in one model was not good enough to be a predictive model. Therefore, an exploratory analysis was conducted by testing several alternative models that combined two of the three existing biomarkers. It turned out that CD4+ TIL in model 2 (CD4+CD8+) and FOXP3+ TIL in model 4 (CD8+FOXP3+) showed significant coefficient values. Moreover, all of the threshold coefficients in model 4 are significant. CONCLUSION: This study shows that CD4+, CD8+, and FOXP3+ TIL have promising potential as predictive biomarkers. In particular, FOXP3+ is dominant in predictive models of pathological response in patients with IBC.

Dexamethasone-Integrated Mesenchymal Stem Cells for Systemic Lupus Erythematosus Treatment via Multiple Immunomodulatory Mechanisms.

The therapeutic application of mesenchymal stem cells (MSCs) has good potential as a treatment strategy for systemic lupus erythematosus (SLE), but traditional MSC therapy still has limitations in effectively modulating immune cells. Herein, we present a promising strategy based on dexamethasone liposome-integrated MSCs (Dexlip-MSCs) for treating SLE via multiple immunomodulatory pathways. This therapeutic strategy prolonged the circulation time of dexamethasone liposomes in vivo, restrained CD4+T-cell proliferation, and inhibited the release of proinflammatory mediators (IFN-γ and TNF-α) by CD4+T cells. In addition, Dexlip-MSCs initiated cellular reprogramming by activating the glucocorticoid receptor (GR) signaling pathway to upregulate the expression of anti-inflammatory factors such as cysteine-rich secretory protein LCCL-containing domain 2 (CRISPLD2) and downregulate the expression of proinflammatory factors. In addition, Dexlip-MSCs synergistically increased the anti-inflammatory inhibitory effect of CD4+T cells through the release of dexamethasone liposomes or Dex-integrated MSC-derived exosomes (Dex-MSC-EXOs). Based on these synergistic biological effects, we demonstrated that Dexlip-MSCs alleviated disease progression in MRL/lpr mice more effectively than Dexlip or MSCs alone. These features indicate that our stem cell delivery strategy is a promising therapeutic approach for clinical SLE treatment.

A novel humanized mouse model for HIV and tuberculosis co-infection studies.

Background: Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), continues to be a major public health problem worldwide. The human immunodeficiency virus (HIV) is another equally important life-threatening pathogen. HIV infection decreases CD4+ T cell levels markedly increasing Mtb co-infections. An appropriate animal model for HIV/Mtb co-infection that can recapitulate the diversity of the immune response in humans during co-infection would facilitate basic and translational research in HIV/Mtb infections. Herein, we describe a novel humanized mouse model. Methods: The irradiated NSG-SGM3 mice were transplanted with human CD34+ hematopoietic stem cells, and the humanization was monitored by staining various immune cell markers for flow cytometry. They were challenged with HIV and/or Mtb, and the CD4+ T cell depletion and HIV viral load were monitored over time. Before necropsy, the live mice were subjected to pulmonary function test and CT scan, and after sacrifice, the lung and spleen homogenates were used to determine Mtb load (CFU) and cytokine/chemokine levels by multiplex assay, and lung sections were analyzed for histopathology. The mouse sera were subjected to metabolomics analysis. Results: Our humanized NSG-SGM3 mice were able to engraft human CD34+ stem cells, which then differentiated into a full-lineage of human immune cell subsets. After co-infection with HIV and Mtb, these mice showed decrease in CD4+ T cell counts overtime and elevated HIV load in the sera, similar to the infection pattern of humans. Additionally, Mtb caused infections in both lungs and spleen, and induced granulomatous lesions in the lungs. Distinct metabolomic profiles were also observed in the tissues from different mouse groups after co-infections. Conclusion: The humanized NSG-SGM3 mice are able to recapitulate the pathogenic effects of HIV and Mtb infections and co-infection at the pathological, immunological and metabolism levels and are therefore a reproducible small animal model for studying HIV/Mtb co-infection.

Paracrine- and cell-contact-mediated immunomodulatory effects of human periodontal ligament-derived mesenchymal stromal cells on CD4+ T lymphocytes.

BACKGROUND: Mesenchymal stromal cells (MSCs) isolated from the periodontal ligament (hPDL-MSCs) have a high therapeutic potential, presumably due to their immunomodulatory properties. The interaction between hPDL-MSCs and immune cells is reciprocal and executed by diverse cytokine-triggered paracrine and direct cell-to-cell contact mechanisms. For the first time, this study aimed to directly compare the contribution of various mechanisms on this reciprocal interaction using different in vitro co-culture models at different inflammatory milieus. METHODS: Three co-culture models were used: indirect with 0.4 µm-pored insert, and direct with or without insert. After five days of co-culturing mitogen-activated CD4+ T lymphocytes with untreated, interleukin (IL)-1ß, or tumor necrosis factor (TNF)-α- treated hPDL-MSCs, the CD4+ T lymphocyte proliferation, viability, and cytokine secretion were investigated. The gene expression of soluble and membrane-bound immunomediators was investigated in the co-cultured hPDL-MSCs. RESULTS: Untreated hPDL-MSCs decreased the CD4+ T lymphocyte proliferation and viability more effectively in the direct co-culture models. The direct co-culture model without inserts showed a strikingly higher CD4+ T lymphocyte cell death rate. Adding IL-1ß to the co-culture models resulted in substantial CD4+ T lymphocyte response alterations, whereas adding TNF resulted in only moderate effects. The most changes in CD4+ T lymphocyte parameters upon the addition of IL-1ß or TNF-α in a direct co-culture model without insert were qualitatively different from those observed in two other models. Additionally, the co-culture models caused variability in the immunomediator gene expression in untreated and cytokine-triggered hPDL-MSCs. CONCLUSION: These results suggest that both paracrine and cell-to-cell contact mechanisms contribute to the reciprocal interaction between hPDL-MSCs and CD4+ T lymphocytes. The inflammatory environment affects each of these mechanisms, which depends on the type of cytokines used for the activation of MSCs' immunomodulatory activities. This fact should be considered by comparing the outcomes of the different models.

Immunomodulatory activity of argentatins A and B isolated from guayule.

Argentatins are secondary metabolites synthesized by guayule (Parthenium argentatum A. Gray) with numerous potential medical applications. In addition to inhibiting insect growth, they are endowed with several pharmacological properties including antimicrobial and antitumorigenic activity. However, their potential as immunomodulators remains unexplored. The aim of the present study was to investigate whether argentatins can modulate the function of the immune system. Human mesenchymal stem cells were treated with argentatins and the production of several anti- and proinflammatory cytokines was evaluated. The effect of argentatins on the polarization of CD4+ T-lymphocytes and macrophages was also assessed. Results demonstrated that argentatins can modulate the production of proinflammatory cytokines and the polarization of cellular phenotypes, including Th2 lymphocytes and M1 macrophages. These findings suggest that argentatins are promising therapeutic agents in autoimmune or allergic diseases, and open new perspectives for the investigation of argentatins in immune response and in the development of more targeted and effective immunomodulatory therapies.

Antigenic Peptide-Thioredoxin Fusion Chimeras for In Vitro Stimulus of CD4+ TCR+ Jurkat T Cells.

Study of CD4+ T cell response and T cell receptor (TCR) specificity is crucial for understanding etiology of immune-mediated diseases and developing targeted therapies. However, solubility, accessibility, and stability of synthetic antigenic peptides used in T cell assays may be a critical point in such studies. Here we present a T cell activation reporter system using recombinant proteins containing antigenic epitopes fused with bacterial thioredoxin (trx-peptides) and obtained by bacterial expression. We report that co-incubation of CD4+ HA1.7 TCR+ reporter Jurkat 76 TRP cells with CD80+ HLA-DRB1*01:01+ HeLa cells or CD4+ Ob.1A12 TCR+ Jurkat 76 TRP with CD80+ HLA-DRB1*15:01+ HeLa cells resulted in activation of reporter Jurkat 76 TPR after addition of recombinant trx-peptide fusion proteins, containing TCR-specific epitopes. Trx-peptides were comparable with corresponding synthetic peptides in their capacity to activate Jurkat 76 TPR. These data demonstrate that thioredoxin as a carrier protein (trx) for antigenic peptides exhibits minimal interference with recognition of MHC-specific peptides by TCRs and consequent T cell activation. Our findings highlight potential feasibility of trx-peptides as a reagent for assessing the immunogenicity of antigenic fragments.

The Adaptive Immune Response in Hepatitis B Virus-Associated Hepatocellular Carcinoma Is Characterized by Dysfunctional and Exhausted HBV-Specific T Cells.

This systematic review investigates the immunosuppressive environment in HBV-associated hepatocellular carcinoma (HCC), characterized by dysfunctional and exhausted HBV-specific T cells alongside an increased infiltration of HBV-specific CD4+ T cells, particularly regulatory T cells (Tregs). Heightened expression of checkpoint inhibitors, notably PD-1, is linked with disease progression and recurrence, indicating its potential as both a prognostic indicator and a target for immunotherapy. Nevertheless, using PD-1 inhibitors has shown limited effectiveness. In a future perspective, understanding the intricate interplay between innate and adaptive immune responses holds promise for pinpointing predictive biomarkers and crafting novel treatment approaches for HBV-associated HCC.