RESUMO
Introduction: α-galactosylceramide (α-GalCer), a prototypical agonist of invariant natural killer T (iNKT) cells, stimulates iNKT cells to produce various cytokines such as IFNγ and IL4. Moreover, repeated α-GalCer treatment can cause protective or pathogenic outcomes in various immune-mediated diseases. However, the precise role of α-GalCer-activated iNKT cells in sepsis development remains unclear. To address this issue, we employed a lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced murine sepsis model and two alternative models. Methods: Sepsis was induced in wild-type (WT) C57BL/6 (B6) mice by three methods (LPS/D-GalN, α-GalCer/D-GalN, and cecal slurry), and these mice were monitored for survival rates. WT B6 mice were intraperitoneally injected with α-GalCer or OCH (an IL4-biased α-GalCer analog) one week prior to the induction of sepsis. To investigate the effects of α-GalCer-mediated iNKT cell activation on sepsis development, immune responses were analyzed by flow cytometry using splenocytes and liver-infiltrating leukocytes. In addition, a STAT6 inhibitor (AS1517499) and an IL10 inhibitor (AS101) were employed to evaluate the involvement of IL4 or IL10 signaling. Furthermore, we performed B cell adoptive transfers to examine the contribution of α-GalCer-induced regulatory B (Breg) cell populations in sepsis protection. Results: In vivo α-GalCer pretreatment polarized iNKT cells towards IL4- and IL10-producing phenotypes, significantly attenuating LPS/D-GalN-induced septic lethality in WT B6 mice. Furthermore, α-GalCer pretreatment reduced the infiltration of immune cells to the liver and attenuated pro-inflammatory cytokine production. Treatment with a STAT6 inhibitor was unable to modulate disease progression, indicating that IL4 signaling did not significantly affect iNKT cell-mediated protection against sepsis. This finding was confirmed by pretreatment with OCH, which did not alter sepsis outcomes. However, interestingly, prophylactic effects of α-GalCer on sepsis were significantly suppressed by treatment with an IL10 antagonist, suggesting induction of IL10-dependent anti-inflammatory responses. In addition to IL10-producing iNKT cells, IL10-producing B cell populations were significantly increased after α-GalCer pretreatment. Conclusion: Overall, our results identify α-GalCer-mediated induction of IL10 by iNKT and B cells as a promising option for controlling the pathogenesis of postoperative sepsis.
Assuntos
Galactosilceramidas , Interleucina-10 , Camundongos Endogâmicos C57BL , Células T Matadoras Naturais , Choque Séptico , Animais , Galactosilceramidas/farmacologia , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/metabolismo , Camundongos , Interleucina-10/metabolismo , Choque Séptico/imunologia , Modelos Animais de Doenças , Linfócitos B/imunologia , Linfócitos B/metabolismo , Masculino , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologiaRESUMO
Type I NKT cells, also known as Invariant Natural Killer T (iNKT) cells, are a subpopulation of unconventional, innate-like T (ILT) cells which can proficiently influence downstream immune effector functions. Type I NKT cells express a semi-invariant αß T cell receptor (TCR) that recognises lipid-based ligands specifically presented by the non-classical cluster of differentiation (CD1) protein d (CD1d) molecule. Due to their potent immunomodulatory functional capacity, type I NKT cells are being increasingly considered in prophylactic and therapeutic approaches towards various diseases, including as vaccine-adjuvants. As viruses do not encode lipid synthesis, it is surprising that many studies have shown that some viruses can directly impede type I NKT activation through downregulating CD1d expression. Therefore, in order to harness type I NKT cells for potential anti-viral therapeutic uses, it is critical that we fully appreciate how the CD1d-iNKT cell axis interacts with viral immunity. In this review, we examine clinical findings that underpin the importance of type I NKT cell function in viral infections. This review also explores how certain viruses employ immunoevasive mechanisms and directly encode functions to target CD1d expression and type I NKT cell function. Overall, we suggest that the CD1d-iNKT cell axis may hold greater gravity within viral infections than what was previously appreciated.
Assuntos
Antígenos CD1d , Células T Matadoras Naturais , Viroses , Células T Matadoras Naturais/imunologia , Humanos , Viroses/imunologia , Animais , Antígenos CD1d/imunologia , Antígenos CD1d/metabolismo , Ativação Linfocitária/imunologiaRESUMO
Introduction: Immunogenicity, the unwanted immune response triggered by therapeutic antibodies, poses significant challenges in biotherapeutic development. This response can lead to the production of anti-drug antibodies, potentially compromising the efficacy and safety of treatments. The internalization of therapeutic antibodies into dendritic cells (DCs) is a critical factor influencing immunogenicity. Using monoclonal antibodies, with differences in non-specific cellular uptake, as tools to explore the impact on the overall risk of immunogenicity, this study explores how internalization influences peptide presentation and subsequently T cell activation. Materials and methods: To investigate the impact of antibody internalization on immunogenicity, untargeted toolantibodies with engineered positive or negative charge patches were utilized. Immature monocyte-derived DCs (moDCs), known for their physiologically relevant high endocytic activity, were employed for internalization assays, while mature moDCs were used for MHC-II associated peptide proteomics (MAPPs) assays. In addition to the lysosomal accumulation and peptide presentation, subsequent CD4+ T cell activation has been assessed. Consequently, a known CD4+ T cell epitope from ovalbumin was inserted into the tool antibodies to evaluate T cell activation on a single, shared epitope. Results: Antibodies with positive charge patches exhibited higher rates of lysosomal accumulation and epitope presentation compared to those with negative charge patches or neutral surface charge. Furthermore, a direct correlation between internalization rate and presentation on MHC-II molecules could be established. To explore the link between internalization, peptide presentation and CD4+ T cell activation, tool antibodies containing the same OVA epitope were used. Previous observations were not altered by the insertion of the OVA epitope and ultimately, an enhanced CD4+ T cell response correlated with increased internalization in DCs and peptide presentation. Discussion: These findings demonstrate that the biophysical properties of therapeutic antibodies, particularly surface charge, play a crucial role in their internalization into DCs. Antibodies internalized faster and processed by DCs, are also more prone to be presented on their surface leading to a higher risk of triggering an immune response. These insights underscore the importance of considering antibody surface charge and other properties that enhance cellular accumulation during the preclinical development of biotherapeutics to mitigate immunogenicity risks.
Assuntos
Apresentação de Antígeno , Células Dendríticas , Ativação Linfocitária , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Humanos , Apresentação de Antígeno/imunologia , Ativação Linfocitária/imunologia , Anticorpos Monoclonais/imunologia , Linfócitos T CD4-Positivos/imunologia , Epitopos de Linfócito T/imunologia , Fatores de Risco , Endocitose/imunologia , Ovalbumina/imunologiaRESUMO
Rationale: Dysregulated T-cell immune response-mediated inflammation plays critical roles in the pathology of diverse liver diseases, but the underlying mechanism of liver immune homeostasis control and the specific therapies for limiting T-cell overactivation remain unclear. Methods: The metabolic changes in concanavalin A (ConA) mice and autoimmune hepatitis (AIH) patients and their associations with liver injury were analyzed. The expression of purine catabolism nucleases (e.g., CD39 and CD73) on liver cells and immune cells was assessed. The effects of MCregs and their extracellular vesicles (EVs) on CD4+ T-cell overactivation and the underlying mechanism were also explored. Results: Our findings revealed significant alterations in purine metabolism in ConA mice and AIH patients, which correlated with liver injury severity and therapeutic response. CD39 and CD73 were markedly upregulated on CD11b+Gr-1+ MCs under liver injury conditions. The naturally expanded CD39+CD73+Gr-1highCD11b+ MCreg subset during early liver injury effectively suppressed CD4+ T-cell hyperactivation and liver injury both in vitro and in vivo. Mechanistically, MCregs released CD73high EVs, which converted extracellular AMP to immunosuppressive metabolites (e.g., adenosine and inosine), activating the cAMP pathway and inhibiting glycolysis and cytokine secretion in activated CD4+ T cells. Conclusions: This study provides insights into the mechanism controlling immune homeostasis during the early liver injury phase and highlights that MCreg or MCreg-EV therapy may be a specific strategy for preventing diverse liver diseases induced by T-cell overactivation.
Assuntos
Vesículas Extracelulares , Hepatite Autoimune , Camundongos Endogâmicos C57BL , Purinas , Animais , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/imunologia , Camundongos , Purinas/metabolismo , Hepatite Autoimune/imunologia , Hepatite Autoimune/metabolismo , Hepatite Autoimune/patologia , Humanos , Apirase/metabolismo , Fígado/metabolismo , Fígado/imunologia , Fígado/patologia , Células Mieloides/metabolismo , Células Mieloides/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Masculino , 5'-Nucleotidase/metabolismo , Ativação Linfocitária/imunologia , Concanavalina A , Feminino , Modelos Animais de Doenças , Inflamação/metabolismo , Inflamação/imunologia , Antígenos CDRESUMO
BACKGROUND: Systemic lupus erythematosus (SLE) is the quintessential autoimmune disease, as it is characterized by hyperactivity of CD4+ T cells and subsequently drives lupus pathology. Follicular helper T (TFH) cells play an important role in B cell maturation and antibody production. However, which specific subset of cTFH cells drives B cell function and contributes to the development of anti-dsDNA antibodies and SLE pathogenesis remains unclear. METHODS: Peripheral blood mononuclear cells from SLE patients with inactive (n = 11) and active (n = 21) were used to determine and detect frequencies and phenotypes of circulating TFH cells (cTFH), memory cTFH, and B cell subsets. The correlations among cTFH cell subsets and phenotypes, B cell subsets, anti-dsDNA autoantibodies, and clinical parameters were analyzed. RESULTS: In subjects with active SLE, cTFH1 and cTFH17 cells were significantly expanded and activated. These expanded cTFH cells expressed memory phenotypes; cTFH1 cells were predominantly central memory (CM) type, while cTFH17 cells were largely effector memory (EM) type. Phenotyping B cell subsets in these patients showed increased frequencies of aNAV and DN2 B cells. Clinically, ICOS+ cTFH1, ICOS+ cTFH17 cells, and SLEDAI-2k scores were found to be correlated. Analysis of cTFH-B cell relationship revealed positive correlations among ICOS+ cTFH1 cells, aNAV B cells, and anti-dsDNA antibodies. Activation of ICOS+ cTFH17 cells was significantly related to the expansion of aNAV and DN2 B cells. The presence of CM cells in cTFH1 and cTFH17 subsets was correlated with aNAV and DN2 B cell frequencies. CONCLUSION: SLE cTFH cells were found to be polarized toward cTFH1 and cTFH17 cells; activation of these cTFH subsets was significantly associated with disease activity score, aNAV, DN2 B cell expansion, and anti-dsDNA antibody level. Thus, the interactions among cTFH1, cTFH17, and B cells likely contribute to the development of autoantibodies and the pathogenesis in SLE.
Assuntos
Lúpus Eritematoso Sistêmico , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/sangue , Feminino , Adulto , Masculino , Pessoa de Meia-Idade , Linfócitos B/imunologia , Ativação Linfocitária/imunologia , Células T Auxiliares Foliculares/imunologia , Células Th17/imunologia , Adulto Jovem , Anticorpos Antinucleares/imunologia , Anticorpos Antinucleares/sangueRESUMO
While adoptive cell therapy has shown success in hematological malignancies, its potential against solid tumors is hindered by an immunosuppressive tumor microenvironment (TME). In recent years, members of the hypoxia-inducible factor (HIF) family have gained recognition as important regulators of T-cell metabolism and function. The role of HIF signalling in activated CD8 T cell function in the context of adoptive cell transfer, however, has not been explored in full depth. Here we utilize CRISPR-Cas9 technology to delete prolyl hydroxylase domain-containing enzymes (PHD) 2 and 3, thereby stabilizing HIF-1 signalling, in CD8 T cells that have already undergone differentiation and activation, modelling the T cell phenotype utilized in clinical settings. We observe a significant boost in T-cell activation and effector functions following PHD2/3 deletion, which is dependent on HIF-1α, and is accompanied by an increased glycolytic flux. This improvement in CD8 T cell performance translates into an enhancement in tumor response to adoptive T cell therapy in mice, across various tumor models, even including those reported to be extremely resistant to immunotherapeutic interventions. These findings hold promise for advancing CD8 T-cell based therapies and overcoming the immune suppression barriers within challenging tumor microenvironments.
Assuntos
Linfócitos T CD8-Positivos , Subunidade alfa do Fator 1 Induzível por Hipóxia , Prolina Dioxigenases do Fator Induzível por Hipóxia , Imunoterapia Adotiva , Microambiente Tumoral , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética , Imunoterapia Adotiva/métodos , Camundongos , Microambiente Tumoral/imunologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Camundongos Endogâmicos C57BL , Linhagem Celular Tumoral , Ativação Linfocitária/imunologia , Sistemas CRISPR-Cas , Humanos , Neoplasias/imunologia , Neoplasias/terapia , Neoplasias/genética , Feminino , Pró-Colágeno-Prolina DioxigenaseRESUMO
BACKGROUND: Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by defective antibody production and impaired differentiation of B cells. B cell proliferation is an essential step for antibody synthesis. Depending on the nature of the stimulus, their response may be either T-cell-dependent or T-cell-independent. METHODS: We studied 23 CVID patients and 14 healthy donors (HD). The patients were categorized based on their percentage of memory B cells. In addition to standard immunophenotyping of circulating human B and T cell subsets, an in vitro CFSE dilution assay was used to assess the proliferative capacity of B cells and to compare the activation of the T cell-dependent and T cell-independent response among the patients. RESULTS: Patients with a reduction in memory B cells exhibited an increase in follicular T cells (Tfh) and showed low proliferation in response to PKW, CpG, and SAC stimuli (Condition II) (p= 0.0073). In contrast, patients with a normal percentage of memory B cells showed a high expression of IL-21R and low proliferation in response to CPG (Condition III); IL-21, CD40L, and anti-IgM (Condition IV) stimuli (p= 0.0163 and p = 0.0475, respectively). CONCLUSION: Defective proliferation in patients depends on the type of stimulus used and the phenotypic characteristics of the patients. Further studies are necessary to understand the disease mechanisms, which may guide us toward identifying genetic defects associated with CVID.
Assuntos
Proliferação de Células , Imunodeficiência de Variável Comum , Ativação Linfocitária , Humanos , Imunodeficiência de Variável Comum/imunologia , Masculino , Feminino , Adulto , Ativação Linfocitária/imunologia , Pessoa de Meia-Idade , Imunofenotipagem , Linfócitos B/imunologia , Adulto Jovem , Células Cultivadas , Células B de Memória/imunologia , Interleucinas/metabolismo , Interleucinas/imunologia , Adolescente , Memória Imunológica/imunologiaRESUMO
Programming cell signaling during T-cell activation represents a simple strategy for improving the potency of therapeutic T-cell products. Stim-R technology (Lyell Immunopharma) is a customizable, degradable synthetic cell biomimetic that emulates physiologic, cell-like presentation of signal molecules to control T-cell activation. A breadth of Stim-R formulations with different anti-CD3/anti-CD28 (αCD3/αCD28) antibody densities and stoichiometries were screened for their effects on multiple metrics of T-cell function. We identified an optimized formulation that produced receptor tyrosine kinase-like orphan receptor 1 (ROR1)-targeted chimeric antigen receptor (CAR) T cells with enhanced persistence and polyfunctionality in vitro, as assessed in repeat-stimulation assays, compared with a benchmark product generated using a conventional T-cell-activating reagent. In transcriptomic analyses, CAR T cells activated with Stim-R technology showed downregulation of exhaustion-associated gene sets and retained a unique subset of stem-like cells with effector-associated gene signatures following repeated exposure to tumor cells. Compared with the benchmark product, CAR T cells activated using the optimized Stim-R technology formulation exhibited higher peak expansion, prolonged persistence, and improved tumor control in a solid tumor xenograft model. Enhancing T-cell products with Stim-R technology during T-cell activation may help improve therapeutic efficacy against solid tumors.
Assuntos
Ativação Linfocitária , Receptores de Antígenos Quiméricos , Transdução de Sinais , Linfócitos T , Receptores de Antígenos Quiméricos/imunologia , Receptores de Antígenos Quiméricos/metabolismo , Receptores de Antígenos Quiméricos/genética , Humanos , Animais , Ativação Linfocitária/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Camundongos , Imunoterapia Adotiva/métodos , Ensaios Antitumorais Modelo de Xenoenxerto , Linhagem Celular Tumoral , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos de Linfócitos T/imunologia , Antígenos CD28/imunologia , Antígenos CD28/metabolismoRESUMO
Gamma/delta (γδ) T cells are unconventional lymphocytes that recognize diverse ligands via somatically recombined T cell antigen receptors (γδ TCRs). The molecular mechanism by which ligand recognition initiates γδ TCR signaling, a process known as TCR triggering, remains elusive. Unlike αß TCRs, γδ TCRs are not mechanosensitive and do not require co-receptors or typical binding-induced conformational changes for triggering. Here, we show that γδ TCR triggering by nonclassical MHC class Ib antigens, a major class of ligands recognized by γδ T cells, requires steric segregation of the large cell-surface phosphatases CD45 and CD148 from engaged TCRs at synaptic close-contact zones. Increasing access of these inhibitory phosphatases to sites of TCR engagement, by elongating MHC class Ib ligands or truncating CD45/148 ectodomains, abrogates TCR triggering and T cell activation. Our results identify a critical step in γδ TCR triggering and provide insight into the core triggering mechanism of endogenous and synthetic tyrosine-phosphorylated immunoreceptors.
Assuntos
Receptores de Antígenos de Linfócitos T gama-delta , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Humanos , Ligantes , Animais , Antígenos Comuns de Leucócito/metabolismo , Ativação Linfocitária/imunologia , Camundongos , Linfócitos T/imunologia , Linfócitos T/metabolismo , FosforilaçãoRESUMO
B-cell lymphoma, clinically, comprises a heterogeneous group of malignancies that encompass various subtypes. CD20 is an optimal target for therapeutic antibodies in B-cell lymphoma immunotherapy since approximately 90% of B-cell malignancies typically exhibit CD20 expression on their surface, while its presence is limited in normal tissues. In this study, we have developed a series of novel non-IgG-like T cell-dependent bispecific antibodies by constructing Fab-FabCH3, referred to as Tandem Antigen-binding Fragment 002 (TFAB002), which specifically target CD20 for the treatment of malignant B-cell lymphoma. TFAB002s display strong binding affinity with CD20 and moderate binding affinity with CD3, thereby triggering target-specific T-cell activation, cytokine release, and tumor cell lysis in vitro. Furthermore, TFAB002s exhibit potent cytotoxicity against B-cell malignancies that express varying levels of CD20. Besides, the TFAB002s show potent pharmacodynamic activity in vivo in the WIL2-S cells CDX mouse model. Collectively, these results underscore the potential of TFAB002s as a highly promising therapeutic approach for selectively depleting CD20-positive B cells, thereby warranting further clinical evaluation as a viable treatment option for CD20-expressing B-cell malignancies.
Assuntos
Anticorpos Biespecíficos , Antígenos CD20 , Fragmentos Fab das Imunoglobulinas , Linfoma de Células B , Linfócitos T , Animais , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/imunologia , Antígenos CD20/imunologia , Linfoma de Células B/imunologia , Linfoma de Células B/terapia , Linfoma de Células B/tratamento farmacológico , Camundongos , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Linfócitos T/imunologia , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto , Ativação Linfocitária/imunologia , Ativação Linfocitária/efeitos dos fármacos , FemininoRESUMO
Upon antigenic stimulation, naïve CD4+ T cells can give rise to phenotypically distinct effector T helper cells and long-lived memory T cells. We computationally reconstructed the in vivo trajectory of CD4+ T cell differentiation during a type I inflammatory immune response and identified two distinct differentiation paths for effector and precursor central memory T cells arising directly from naïve CD4+ T cells. Unexpectedly, our studies revealed heterogeneity among naïve CD4+ T cells, which are typically considered homogeneous save for their diverse T cell receptor usage. Specifically, a previously unappreciated population of naïve CD4+ T cells sensing environmental type I IFN exhibited distinct activation thresholds, suggesting that naïve CD4+ T cell differentiation potential may be influenced by environmental cues. This population was expanded in human viral infection and type I IFN response-lined autoimmunity. Understanding the relevance of naïve T cell heterogeneity to beneficial and maladaptive T cell responses may have therapeutic implications for adoptive T cell therapies in cancer immunotherapy and vaccination.
Assuntos
Linfócitos T CD4-Positivos , Diferenciação Celular , Memória Imunológica , Células T de Memória , Humanos , Linfócitos T CD4-Positivos/imunologia , Diferenciação Celular/imunologia , Animais , Memória Imunológica/imunologia , Células T de Memória/imunologia , Camundongos , Interferon Tipo I/metabolismo , Interferon Tipo I/imunologia , Ativação Linfocitária/imunologiaRESUMO
Rheumatoid arthritis (RA) is a systemic autoimmune disease, mediated by a complex interaction between B cells and various subsets of T cells. Dysfunction of helper T (Th) and regulatory T (Treg) cells may contribute to the breakdown of self-tolerance and the progression of autoimmune disease. In this study, we investigated the activity of Th and Treg cells on the differentiation of autologous B cells in vitro using cell cultures from the peripheral blood of healthy controls (HCs) and RA patients. The expressions of programmed death 1 (PD-1) and IL-21 were monitored as activation markers for Th cells. Unstimulated Th cells from RA patients showed remarkably higher PD-1 expression than HC samples. Stimulation of Th cells from RA patients with Staphylococcus enterotoxin B (SEB) in the presence of B cells significantly induced their PD-1 and IL-21 expression at a considerably higher level in RA compared to HCs, and Treg cells did not affect IL-21 production. When monitoring B-cell differentiation, a significantly higher frequency of plasma cells was observed, even in unstimulated samples of RA patients compared to HCs. In the SEB-stimulated co-cultures of the RA samples, plasma cell frequency and IgG production were considerably higher than in HCs and were not significantly affected by Tregs. These findings demonstrate that Th cells are constitutively active in RA, and their hyperactivity upon interaction with diseased B cells may lead to uncontrolled antibody production.
Assuntos
Artrite Reumatoide , Linfócitos B , Interleucinas , Receptor de Morte Celular Programada 1 , Linfócitos T Auxiliares-Indutores , Linfócitos T Reguladores , Humanos , Artrite Reumatoide/imunologia , Artrite Reumatoide/metabolismo , Feminino , Receptor de Morte Celular Programada 1/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Masculino , Interleucinas/metabolismo , Pessoa de Meia-Idade , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Formação de Anticorpos/imunologia , Diferenciação Celular/imunologia , Adulto , Enterotoxinas/imunologia , Células Cultivadas , Idoso , Ativação Linfocitária/imunologia , Técnicas de CoculturaRESUMO
PD-1 is a key negative regulator of CD8+ T cell activation and is highly expressed by exhausted T cells in cancer and chronic viral infection. Although PD-1 blockade can improve viral and tumor control, physiological PD-1 expression prevents immunopathology and improves memory formation. The mechanisms driving high PD-1 expression in exhaustion are not well understood and could be critical to disentangling its beneficial and detrimental effects. Here, we functionally interrogated the epigenetic regulation of PD-1 using a mouse model with deletion of an exhaustion-specific PD-1 enhancer. Enhancer deletion exclusively alters PD-1 expression in CD8+ T cells in chronic infection, creating a 'sweet spot' of intermediate expression where T cell function is optimized compared to wild-type and Pdcd1-knockout cells. This permits improved control of chronic infection without additional immunopathology. Together, these results demonstrate that tuning PD-1 via epigenetic editing can reduce CD8+ T cell dysfunction while avoiding excess immunopathology.
Assuntos
Linfócitos T CD8-Positivos , Epigênese Genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor de Morte Celular Programada 1 , Animais , Receptor de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/genética , Linfócitos T CD8-Positivos/imunologia , Camundongos , Ativação Linfocitária/imunologia , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Elementos Facilitadores Genéticos/genéticaRESUMO
T-cell activation is central for the initiation of T cell mediated adaptive immune response and is the result of the close communication between the Antigen Presenting Cell (APC) and the T lymphocyte. Although T-cell activation is currently well understood, and many intracellular pathways are well characterized, nevertheless new players are constantly identified, and this complements the known protein interactome. In this work we aimed to identify new proteins involved in T cell activation. We reviewed and analyzed results of microarray gene expression datasets reported in the public database GEO-NCBI. Using data from GSE136625, GSE50971, GSE13887, GSE11989 and GSE902 we performed different comparisons using R and other bioinformatic tools including GEO2R and we report here upregulated genes that have no previous reports in immune related functions and with potential participation upon T-cell activation. Our results indicate that RND3, SYT10, IgSF6 and PIN1 are potential new T-cell activation molecules.
Assuntos
Biologia Computacional , Ativação Linfocitária , Linfócitos T , Ativação Linfocitária/imunologia , Biologia Computacional/métodos , Humanos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Perfilação da Expressão GênicaRESUMO
Luteolin, a commonly used traditional Chinese medicine, has been utilized for several decades in the treatment of hepatocellular carcinoma (HCC). Previous research has demonstrated its anti-tumour efficacy, but its underlying mechanism remains unclear. This study aimed to assess the therapeutic effects of luteolin in H22 tumour-bearing mice. luteolin effectively inhibited the growth of solid tumours in a well-established mouse model of HCC. High-throughput sequencing revealed that luteolin treatment could enhance T-cell activation, cell chemotaxis and cytokine production. In addition, luteolin helped sustain a high ratio of CD8+ T lymphocytes in the spleen, peripheral blood and tumour tissues. The effects of luteolin on the phenotypic and functional changes in tumour-infiltrating CD8+ T lymphocytes were also investigated. Luteolin restored the cytotoxicity of tumour-infiltrating CD8+ T lymphocytes in H22 tumour-bearing mice. The CD8+ T lymphocytes exhibited intensified phenotype activation and increased production of granzyme B, IFN-γ and TNF-α in serum. The combined administration of luteolin and the PD-1 inhibitor enhanced the anti-tumour effects in H22 tumour-bearing mice. Luteolin could exert an anti-tumour immune response by inducing CD8+ T lymphocyte infiltration and enhance the anti-tumour effects of the PD-1 inhibitor on H22 tumour-bearing mice.
Assuntos
Linfócitos T CD8-Positivos , Carcinoma Hepatocelular , Neoplasias Hepáticas , Luteolina , Linfócitos do Interstício Tumoral , Luteolina/farmacologia , Luteolina/uso terapêutico , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/patologia , Camundongos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/metabolismo , Linhagem Celular Tumoral , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologia , Citocinas/metabolismo , Masculino , Granzimas/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Camundongos Endogâmicos C57BLRESUMO
Natural Killer (NK) cells, integral components of the innate immune system, play a crucial role in the protection against intracellular threats. Their cytotoxic power requires that activation is tightly controlled, and in this, they take a unique position within the immune system. Rather than depending on the engagement of a single activating receptor, their activation involves a delicate balance between inhibitory and activating signals mediated through an array of surface molecules. Only when this cumulative balance surpasses a specific threshold do NK cells initiate their activity. Remarkably, the activation threshold of NK cells remains robust even when cells express vastly different repertoires of inhibitory and activating receptors. These threshold values seem to be influenced by NK cell interactions with their environment during development and after release from the bone marrow. Understanding how NK cells integrate this intricate pattern of stimuli is an ongoing area of research, particularly relevant for cellular therapies seeking to harness the anti-cancer potential of these cells by modifying surface receptor expression. In this review, we will explore some of the current dogmas regarding NK cell activation and discuss recent literature addressing advances in our understanding of this field.
Assuntos
Células Matadoras Naturais , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Humanos , Animais , Ativação Linfocitária/imunologia , Transdução de SinaisRESUMO
Conventional CD4+ T lymphocytes consist of naïve, foreign antigen-specific memory, and self-antigen-driven memory-phenotype (MP) cell compartments at homeostasis. We recently showed that MP cells tonically proliferate in response to self-antigens and differentiate into the T-bet+ subset in steady state. How excess proliferation and differentiation of MP cells are inhibited remains unclear. Given immunosuppressive function of regulatory T cells (Tregs), it is possible that they are also involved in inhibition of spontaneous MP cell activation. Here we show using Foxp3-diphtheria toxin receptor-transgenic mice that both MP and naïve CD4+ T cells spontaneously proliferate and differentiate into Th1 cells upon acute Treg depletion. At an early time point post Treg depletion, MP as compared to naïve CD4+ T cells are preferentially activated while at a later stage, the response is dominated by activated cells originated from the naïve pool. Moreover, we argue that MP cell proliferation is driven by TCR and CD28 signaling whereas Th1 differentiation mediated by IL-2. Furthermore, our data indicate that such activation of MP and naïve CD4+ T lymphocytes contribute to development of multi-organ inflammation at early and later time points, respectively, after Treg ablation. Together our findings reveal that Tregs tonically inhibit early, spontaneous proliferation and Th1 differentiation of MP CD4+ T lymphocytes as well as late activation of naïve cells, thereby contributing to maintenance of T cell homeostasis.
Assuntos
Memória Imunológica , Ativação Linfocitária , Camundongos Transgênicos , Linfócitos T Reguladores , Animais , Linfócitos T Reguladores/imunologia , Camundongos , Ativação Linfocitária/imunologia , Diferenciação Celular/imunologia , Células T de Memória/imunologia , Células T de Memória/metabolismo , Linfócitos T CD4-Positivos/imunologia , Camundongos Endogâmicos C57BL , Células Th1/imunologia , Proliferação de Células , Fenótipo , Transdução de SinaisRESUMO
Introduction: Adjuvants added to subunit vaccines augment antigen-specific immune responses. One mechanism of adjuvant action is activation of pattern recognition receptors (PRRs) on innate immune cells. Bordetella colonization factor A (BcfA); an outer membrane protein with adjuvant function, activates TH1/TH17-polarized immune responses to protein antigens from Bordetella pertussis and SARS CoV-2. Unlike other adjuvants, BcfA does not elicit a TH2 response. Methods: To understand the mechanism of BcfA-driven TH1/TH17 vs. TH2 activation, we screened PRRs to identify pathways activated by BcfA. We then tested the role of this receptor in the BcfA-mediated activation of bone marrow-derived dendritic cells (BMDCs) using mice with germline deletion of TLR4 to quantify upregulation of costimulatory molecule expression and cytokine production in vitro and in vivo. Activity was also tested on human PBMCs. Results: PRR screening showed that BcfA activates antigen presenting cells through murine TLR4. BcfA-treated WT BMDCs upregulated expression of the costimulatory molecules CD40, CD80, and CD86 and produced IL-6, IL-12/23 p40, and TNF-α while TLR4 KO BMDCs were not activated. Furthermore, human PBMCs stimulated with BcfA produced IL-6. BcfA-stimulated murine BMDCs also exhibited increased uptake of the antigen DQ-OVA, supporting a role for BcfA in improving antigen presentation to T cells. BcfA further activated APCs in murine lungs. Using an in vitro TH cell polarization system, we found that BcfA-stimulated BMDC supernatant supported TFH and TH1 while suppressing TH2 gene programming. Conclusions: Overall, these data provide mechanistic understanding of how this novel adjuvant activates immune responses.
Assuntos
Adjuvantes Imunológicos , Células Th1 , Células Th2 , Receptor 4 Toll-Like , Animais , Receptor 4 Toll-Like/imunologia , Receptor 4 Toll-Like/metabolismo , Camundongos , Células Th1/imunologia , Células Th2/imunologia , Adjuvantes Imunológicos/farmacologia , Humanos , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/metabolismo , Camundongos Knockout , Células Dendríticas/imunologia , Camundongos Endogâmicos C57BL , Células T Auxiliares Foliculares/imunologia , Citocinas/metabolismo , Ativação Linfocitária/imunologiaRESUMO
Bacterial superantigens are T-cell-stimulatory protein molecules which produce massive cytokines and cause human diseases. Due to their ability to activate up to 20% of resting T-cells, they have effectively killed T-cell-dependent tumours in vivo. However, the intrinsic toxicity of whole SAg molecules highlights the urgent need to develop more effective and safer SAg-based immunotherapy. With its unique approach, our study is a significant step towards developing safer tumour-targeted superantigen peptides (TTSP). We identified the T-cell activation function regions on the SEA superantigen and produced variants with minimal lethality, ensuring a safer approach to cancer treatment. This involved the creation of twenty 50-amino-acid-long overlapping peptides covering the full-length SEA superantigen (P1-P20). We then screened these peptides for T-cell activation, successfully isolating two peptides (P5 and P15) with significant T-cell activation. These selected peptides were used to design and synthesise tumour-targeted superantigen peptides, which were linked to a cancer-specific third loop (L3) of transforming growth factor-α (TGF-α), TGFαL3 from either a C' or N' terminal with an eight-amino-acid flexible linker in between. We also produced several P15 variants by changing single amino acids or by amino acid deletions. The novel molecules were then investigated for cytokine production and tumour-targeted killing. The findings from our previous study and the current work open up new avenues for peptide-based immunotherapy, particularly when combined with other immunotherapy techniques, thereby ensuring effective and safer cancer treatment.
Assuntos
Imunoterapia , Peptídeos , Superantígenos , Superantígenos/imunologia , Imunoterapia/métodos , Humanos , Animais , Peptídeos/imunologia , Peptídeos/química , Camundongos , Neoplasias/terapia , Neoplasias/imunologia , Linfócitos T/imunologia , Ativação Linfocitária/imunologia , Linhagem Celular Tumoral , Enterotoxinas/imunologia , Enterotoxinas/química , Medicina de Precisão/métodosRESUMO
Functionally bivalent non-covalent Fab dimers (Bi-Fabs) specific for the TCR/CD3 complex promote CD3 signaling on T cells. While comparing functional responses to stimulation with Bi-Fab, F(ab')2 or mAb specific for the same CD3 epitope, we observed fratricide requiring anti-CD3 bridging of adjacent T cells. Surprisingly, anti-CD3 Bi-Fab ranked first in fratricide potency, followed by anti-CD3 F(ab')2 and anti-CD3 mAb. Low resolution structural studies revealed anti-CD3 Bi-Fabs and F(ab')2 adopt similar global shapes with CD3-binding sites oriented outward. However, under molecular dynamic simulations, anti-CD3 Bi-Fabs crosslinked CD3 more rigidly than F(ab')2. Furthermore, molecular modelling of Bi-Fab and F(ab')2 binding to CD3 predicted crosslinking of T cell antigen receptors located in opposing plasma membrane domains, a feature fitting with T cell fratricide observed. Thus, increasing rigidity of Fab-CD3 crosslinking between opposing effector-target pairs may result in stronger T cell effector function. These findings could guide improving clinical performance of bi-specific anti-CD3 drugs.