RESUMEN
NK cells are cytotoxic innate immune cells involved in antitumor immunity, and they provide a treatment option for patients with acute myeloid leukemia (AML). In this issue of the JCI, Cubitt et al. investigated the role of CD8α, a coreceptor present on approximately 40% of human NK cells. IL-15 stimulation of CD8α- NK cells induced CD8α expression via the RUNX3 transcription factor, driving formation of a unique induced CD8α (iCD8α+) population. iCD8α+ NK cells displayed higher proliferation, metabolic activity, and antitumor cytotoxic function compared with preexisting CD8α+ and CD8α- subsets. Therefore, CD8α expression can be used to define a potential dynamic spectrum of NK cell expansion and function. Because these cells exhibit enhanced tumor control, they may be used to improve in NK cell therapies for patients with AML.
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Antígenos CD8 , Subunidad alfa 3 del Factor de Unión al Sitio Principal , Interleucina-15 , Células Asesinas Naturales , Leucemia Mieloide Aguda , Humanos , Antígenos CD8/metabolismo , Antígenos CD8/inmunología , Antígenos CD8/genética , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 3 del Factor de Unión al Sitio Principal/metabolismo , Subunidad alfa 3 del Factor de Unión al Sitio Principal/inmunología , Interleucina-15/inmunología , Interleucina-15/metabolismo , Interleucina-15/genética , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Leucemia Mieloide Aguda/inmunología , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismoRESUMEN
Chimeric antigen receptor (CAR)-T cells have demonstrated clinical potential, but current receptors still need improvements to be successful against chronic HIV infection. In this study, we address some requirements of CAR motifs for strong surface expression of a novel anti-HIV CAR by evaluating important elements in the extracellular, hinge, and transmembrane (TM) domains. When combining a truncated CD4 extracellular domain and CD8α hinge/TM, the novel CAR did not express extracellularly but was detectable intracellularly. By shortening the CD8α hinge, CD4-CAR surface expression was partially recovered and addition of the LYC motif at the end of the CD8α TM fully recovered both intracellular and extracellular CAR expression. Mutation of LYC to TTA or TTC showed severe abrogation of CAR expression by flow cytometry and confocal microscopy. Additionally, we determined that CD4-CAR surface expression could be maximized by the removal of FQKAS motif at the junction of the extracellular domain and the hinge region. CD4-CAR surface expression also resulted in cytotoxic CAR T cell killing of HIV Env+ target cells. In this study, we identified elements that are crucial for optimal CAR surface expression, highlighting the need for structural analysis studies to establish fundamental guidelines of CAR designs.
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Antígenos CD4 , Receptores Quiméricos de Antígenos , Humanos , Receptores Quiméricos de Antígenos/inmunología , Receptores Quiméricos de Antígenos/metabolismo , Receptores Quiméricos de Antígenos/genética , Antígenos CD4/metabolismo , Antígenos CD4/inmunología , Infecciones por VIH/inmunología , Dominios Proteicos , Células HEK293 , Antígenos CD8/inmunología , Antígenos CD8/metabolismo , Membrana Celular/metabolismo , Secuencias de Aminoácidos , VIH-1/inmunologíaRESUMEN
The dog is an important companion animal and also serves as model species for human diseases. Given the central role of T cells in immune responses, a basic understanding of canine conventional T cell receptor (TCR)αß+ T cells, comprising CD4+ single-positive (sp) T helper (Th) and CD8α+ sp cytotoxic T cell subsets, is available. However, characterization of canine non-conventional TCRαß+ CD4+CD8α+ double-positive (dp) and TCRαß+ CD4-CD8α- double-negative (dn) T cells is limited. In this study, we performed a comprehensive analysis of canine dp and dn T cells in comparison with their conventional counterparts. TCRαß+ T cells from peripheral blood of healthy dogs were sorted according to their CD4/CD8α phenotype into four populations (i.e. CD4+ sp, CD8α+ sp, dp, and dn) and selected surface markers, transcription factors and effector molecules were analyzed ex vivo and after in vitro stimulation by RT-qPCR. Novel characteristics of canine dp T cells were identified, expanding the previously characterized Th1-like phenotype to Th17-like and Th2-like properties. Overall, mRNA expression of various Th cell-associated cytokines (i.e. IFNG, IL17A, IL4, IL13) in dp T cells upon stimulation highlights their versatile immunological potential. Furthermore, we demonstrated that the CD4-CD8α- dn phenotype is stable during in vitro stimulation. Strikingly, dn T cells were found to express highest mRNA levels of type 2 effector cytokines (IL4, IL5, and IL13) upon stimulation. Their strong ability to produce IL-4 was confirmed at the protein level. Upon stimulation, the percentage of IL-4-producing cells was even higher in the non-conventional dn than in the conventional CD4+ sp population. Constitutive transcription of IL1RL1 (encoding IL-33Rα) further supports Th2-like properties within the dn T cell population. These data point to a role of dn T cells in type 2 immunity. In addition, the high potential of dn T cells to transcribe the gene encoding the co-inhibitory receptor CTLA-4 and to produce the inhibitory cytokine IL-10 indicates putative immunosuppressive capacity of this population. In summary, this study reveals important novel aspects of canine non-conventional T cells providing the basis for further studies on their effector and/or regulatory functions to elucidate their role in health and disease.
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Receptores de Antígenos de Linfocitos T alfa-beta , Células Th2 , Animales , Perros , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Células Th2/inmunología , Antígenos CD8/metabolismo , Antígenos CD8/inmunología , Citocinas/metabolismo , Antígenos CD4/metabolismo , Antígenos CD4/inmunología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Inmunofenotipificación , MasculinoRESUMEN
The surface receptor CD8α is present on 20%-80% of human (but not mouse) NK cells, yet its function on NK cells remains poorly understood. CD8α expression on donor NK cells was associated with a lack of therapeutic responses in patients with leukemia in prior studies, thus, we hypothesized that CD8α may affect critical NK cell functions. Here, we discovered that CD8α- NK cells had improved control of leukemia in xenograft models compared with CD8α+ NK cells, likely due to an enhanced capacity for proliferation. Unexpectedly, we found that CD8α expression was induced on approximately 30% of previously CD8α- NK cells following IL-15 stimulation. These induced CD8α+ (iCD8α+) NK cells had the greatest proliferation, responses to IL-15 signaling, and metabolic activity compared with those that sustained existing CD8α expression (sustained CD8α+) or those that remained CD8α- (persistent CD8α-). These iCD8α+ cells originated from an IL-15Rßhi NK cell population, with CD8α expression dependent on the transcription factor RUNX3. Moreover, CD8A CRISPR/Cas9 deletion resulted in enhanced responses through the activating receptor NKp30, possibly by modulating KIR inhibitory function. Thus, CD8α status identified human NK cell capacity for IL-15-induced proliferation and metabolism in a time-dependent fashion, and its presence had a suppressive effect on NK cell-activating receptors.
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Antígenos CD8 , Proliferación Celular , Interleucina-15 , Células Asesinas Naturales , Activación de Linfocitos , Humanos , Antígenos CD8/metabolismo , Antígenos CD8/inmunología , Antígenos CD8/genética , Interleucina-15/inmunología , Interleucina-15/metabolismo , Interleucina-15/genética , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismoRESUMEN
Activated CD8+ T cells directly kill target cells. Therefore, the regulation of their function is central to avoiding immunopathology. Mechanisms that curb effector functions in CD4+ and CD8+ T cells are mostly shared, yet important differences occur. Here, we focus on the control of CD8+ T cell activity and discuss the importance of a poorly understood aspect of tolerance that directly impairs engagement of target cells: the downregulation of CD8. We contextualize this process and propose that it represents a key element during CD8+ T cell modulation.
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Linfocitos T CD8-positivos , Tolerancia Inmunológica , Animales , Humanos , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/metabolismo , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Regulación hacia Abajo/inmunología , Activación de Linfocitos/inmunologíaRESUMEN
BACKGROUND: Cryptosporidium parvum is a protozoan parasite of medical and veterinary importance that causes neonatal diarrhea in many vertebrate hosts. In this study, we evaluated the efficacy of an affinity-purified antigen as a C. parvum vaccine candidate using ileal and liver tissues of experimentally infected neonatal mice by immunohistochemical profiling and immune scoring of CD4+, CD8+, Caspase-3, and nuclear factor kappa B (NF-κB). This vaccine was prepared from the C. parvum oocysts antigen using immune affinity chromatography with cyanogen bromide-activated Sepharose-4B beads. METHODS: Thirty neonatal mice were divided into three groups (10 mice/group): (1) non-immunized non-infected, (2) non-immunized infected (using gastric tubes with a single dose of 1 × 105 of C. parvum oocysts in 250 µl PBS solution 1 h before a meal) and (3) immunized (twice with 40 µg/kg of purified C. parvum antigen at 2-week intervals and then infected with 1 × 105 C. parvum oocysts simultaneously with the second group). After euthanizing the animals on the 10th day, post-infection, their ileal and liver tissues were collected and prepared for immunohistochemistry (IHC) staining to detect CD4+, CD8+, Caspase-3, and NF-κB levels, which are indicators for T helper cells, cytotoxic T cells, apoptosis, and inflammation, respectively. RESULTS: The IHC results showed that CD4+, CD8+, Caspase-3, and NF-κB expression varied significantly (P < 0.001) in both organs in all the groups. We also recorded high CD4+ levels and low CD8+ expression in the non-immunized non-infected mice tissues, while the opposite was observed in the non-immunized infected mice tissues. In the immunized infected mice, the CD4+ level was higher than CD8 + in both organs. While the Caspase-3 levels were higher in the ileal tissue of non-immunized infected than immunized infected mice ileal tissues, the reverse was seen in the liver tissues of both groups. Furthermore, NF-κB expression was higher in the liver tissues of non-immunized infected mice than in immunized infected mice tissues. Therefore, the IHC results and immune-scoring program revealed a significant difference (P < 0.001) in the CD4+, CD8+, Caspase-3, and NF-κB expression levels in both ileal and liver tissues of all mice groups, which might be necessary for immunomodulation in these tissues. CONCLUSIONS: The improvement observed in the immunized infected mice suggests that this vaccine candidate might protect against cryptosporidiosis.
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Antígenos CD4 , Antígenos CD8 , Caspasa 3 , Criptosporidiosis , FN-kappa B , Vacunas Antiprotozoos , Animales , Ratones , Caspasa 3/biosíntesis , Caspasa 3/inmunología , Antígenos CD4/biosíntesis , Antígenos CD4/inmunología , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/biosíntesis , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Criptosporidiosis/prevención & control , Criptosporidiosis/parasitología , Cryptosporidium , Cryptosporidium parvum/inmunología , Inmunohistoquímica , FN-kappa B/biosíntesis , FN-kappa B/inmunología , Vacunas Antiprotozoos/uso terapéutico , VacunasRESUMEN
Historically, the immune system was believed to develop along a linear axis of maturity from fetal life to adulthood. Now, it is clear that distinct layers of immune cells are generated from unique waves of hematopoietic progenitors during different windows of development. This model, known as the layered immune model, has provided a useful framework for understanding why distinct lineages of B cells and γδ T cells arise in succession and display unique functions in adulthood. However, the layered immune model has not been applied to CD8+ T cells, which are still often viewed as a uniform population of cells belonging to the same lineage, with functional differences between cells arising from environmental factors encountered during infection. Recent studies have challenged this idea, demonstrating that not all CD8+ T cells are created equally and that the functions of individual CD8+ T cells in adults are linked to when they were created in the host. In this review, we discuss the accumulating evidence suggesting there are distinct ontogenetic subpopulations of CD8+ T cells and propose that the layered immune model be extended to the CD8+ T cell compartment.
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Linfocitos T CD8-positivos , Sistema Inmunológico , Subgrupos de Linfocitos T , Humanos , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Desarrollo Humano/fisiología , Sistema Inmunológico/citología , Sistema Inmunológico/crecimiento & desarrollo , Sistema Inmunológico/inmunología , Sistema Inmunológico/fisiología , Inmunidad/inmunología , Inmunidad/fisiología , Subgrupos de Linfocitos T/inmunologíaRESUMEN
The microbiome contributes to the development and maturation of the immune system. In response to commensal bacteria, intestinal CD4+ T lymphocytes differentiate into functional subtypes with regulatory or effector functions. The development of small intestine intraepithelial lymphocytes that coexpress CD4 and CD8αα homodimers (CD4IELs) depends on the microbiota. However, the identity of the microbial antigens recognized by CD4+ T cells that can differentiate into CD4IELs remains unknown. We identified ß-hexosaminidase, a conserved enzyme across commensals of the Bacteroidetes phylum, as a driver of CD4IEL differentiation. In a mouse model of colitis, ß-hexosaminidase-specific lymphocytes protected against intestinal inflammation. Thus, T cells of a single specificity can recognize a variety of abundant commensals and elicit a regulatory immune response at the intestinal mucosa.
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Bacteroidetes , Linfocitos T CD4-Positivos , Colitis , Mucosa Intestinal , beta-N-Acetilhexosaminidasas , Animales , Bacteroidetes/enzimología , Bacteroidetes/inmunología , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/inmunología , Colitis/inmunología , Colitis/microbiología , Modelos Animales de Enfermedad , Mucosa Intestinal/inmunología , Mucosa Intestinal/microbiología , Ratones , Ratones Endogámicos C57BL , beta-N-Acetilhexosaminidasas/inmunologíaRESUMEN
CD4-CD8- (double-negative, DN) T cells are critical orchestrators of the cytokine network associated with the pathogenic inflammatory response in one of the deadliest cardiomyopathies known, Chagas heart disease, which is caused by Trypanosoma cruzi infection. Here, studying the distribution, activation status, and cytokine expression of memory DN T-cell subpopulations in Chagas disease patients without cardiac involvement (indeterminate form-IND) or with Chagas cardiomyopathy (CARD), we report that while IND patients displayed a higher frequency of central memory, CARD had a high frequency of effector memory DN T cells. In addition, central memory DN T cells from IND displayed a balanced cytokine profile, characterized by the concomitant expression of IFN-γ and IL-10, which was not observed in effector memory DN T cells from CARD. Supporting potential clinical relevance, we found that the frequency of central memory DN T cells was associated with indicators of better ventricular function, while the frequency of effector memory DN T cells was not. Importantly, decreasing CD1d-mediated activation of DN T cells led to an increase in IL-10 expression by effector memory DN T cells from CARD, restoring a balanced profile similar to that observed in the protective central memory DN T cells. Targeting the activation of effector memory DN T cells may emerge as a strategy to control inflammation in Chagas cardiomyopathy and potentially in other inflammatory diseases where these cells play a key role.
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Antígenos CD4/inmunología , Antígenos CD8/inmunología , Cardiomiopatía Chagásica/inmunología , Enfermedad de Chagas/inmunología , Células T de Memoria/inmunología , Trypanosoma cruzi/inmunología , Adulto , Anciano , Animales , Antígenos CD1d/inmunología , Antígenos CD1d/metabolismo , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Células Cultivadas , Cardiomiopatía Chagásica/metabolismo , Cardiomiopatía Chagásica/parasitología , Enfermedad de Chagas/metabolismo , Enfermedad de Chagas/parasitología , Chlorocebus aethiops , Electrocardiografía , Femenino , Humanos , Interleucina-10/inmunología , Interleucina-10/metabolismo , Masculino , Células T de Memoria/metabolismo , Persona de Mediana Edad , Trypanosoma cruzi/fisiología , Función Ventricular Izquierda/inmunología , Función Ventricular Izquierda/fisiología , Células VeroRESUMEN
Classical dendritic cells (cDCs) in mice have been divided into 2 major subsets based on the expression of nuclear transcription factors: a CD8+Irf8+Batf3 dependent (DC1) subset, and a CD8-Irf4+ (DC2) subset. We found that the CD8+DC1 subset can be further divided into CD8+DC1a and CD8+DC1b subsets by differences in surface receptors, gene expression, and function. Whereas all 3 DC subsets can act alone to induce potent Th1 cytokine responses to class I and II MHC restricted peptides derived from ovalbumin (OVA) by OT-I and OT-II transgenic T cells, only the DC1b subset could effectively present glycolipid antigens to natural killer T (NKT) cells. Vaccination with OVA protein pulsed DC1b and DC2 cells were more effective in reducing the growth of the B16-OVA melanoma as compared to pulsed DC1a cells in wild type mice. In conclusion, the Batf3-/- dependent DC1 cells can be further divided into two subsets with different immune functional profiles in vitro and in vivo.
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Antígenos CD8/inmunología , Células Dendríticas/inmunología , Activación de Linfocitos/inmunología , Transcriptoma/inmunología , Animales , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , FenotipoRESUMEN
Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in B cell malignancies. However, high tumor burden limits clinical efficacy and increases the risk of cytokine release syndrome and neurotoxicity, which is associated with over-activation of the CAR-T cells. The hinge domain plays an important role in the function of CAR-T cells. We hypothesized that deletion of glycine, an amino acid with good flexibility, may reduce the flexibility of the hinge region, thereby mitigating CAR-T cell over-activation. This study involved generating a novel CAR by deletion of two consecutive glycine residues in the CD8 hinge domain of second-generation (2nd) CAR, thereafter named 2nd-GG CAR. The 2nd-GG CAR-T cells showed similar efficacy of CAR expression but lower hinge flexibility, and its protein affinity to CD19 protein was lower than that of 2nd CAR-T cells. Compared to the 2nd CAR-T cells, 2nd-GG CAR-T cells reduced proinflammatory cytokine secretion without diminishing the specific cytotoxicity toward tumor cells in vitro. Furthermore, 2nd-GG CAR-T cells prolonged overall survival in an immunodeficient mouse model bearing NALM-6 when tumor burden was high. This study demonstrated that a lower-flexibility of CD8α hinge improved survival under high tumor burden and reduced proinflammatory cytokines in preclinical studies. While there is potential for improved safety and efficacy, yet this needs validation with clinical trials.
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Antígenos CD8/inmunología , Citocinas/metabolismo , Leucemia Linfocítica Crónica de Células B/terapia , Receptores Quiméricos de Antígenos/inmunología , Linfocitos T/inmunología , Animales , Antígenos CD19/genética , Antígenos CD19/inmunología , Antígenos CD8/genética , Línea Celular Tumoral , Femenino , Humanos , Inmunoterapia Adoptiva/métodos , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/inmunología , Leucemia Linfocítica Crónica de Células B/patología , Transfusión de Linfocitos , Ratones , Ratones SCID , Receptores Quiméricos de Antígenos/genética , Análisis de Supervivencia , Linfocitos T/citología , Linfocitos T/trasplante , Transducción Genética , Carga Tumoral , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Naïve T (Tn) cells require two homeostatic signals for long-term survival: tonic T cell receptor:self-peptide-MHC contact and IL-7 stimulation. However, how microbial exposure impacts Tn homeostasis is still unclear. Here we show that infections can lead to the expansion of a subpopulation of long-lived, Ly6C+ CD8+ Tn cells with accelerated effector function. Mechanistically, mono-infection with West Nile virus transiently, and polymicrobial exposure persistently, enhances Ly6C expression selectively on CD5hiCD8+ cells, which in the case of polyinfection translates into a numerical CD8+ Tn cell increase in the lymph nodes. This conversion and expansion of Ly6C+ Tn cells depends on IFN-I, which upregulates MHC class I expression and enhances tonic TCR signaling in differentiating Tn cells. Moreover, for Ly6C+CD8+ Tn cells, IFN-I-mediated signals optimize their homing to secondary sites, extend their lifespan, and enhance their effector differentiation and antibacterial function, particularly for low-affinity clones. Our results thus uncover significant regulation of Tn homeostasis and function via infection-driven IFN-I, with potential implications for immunotherapy.
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Antígenos Ly/genética , Linfocitos T CD8-positivos/inmunología , Homeostasis/genética , Memoria Inmunológica/genética , Interferón-alfa/genética , Interferón gamma/genética , Fiebre del Nilo Occidental/genética , Animales , Antígenos Ly/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/virología , Antígenos CD5/genética , Antígenos CD5/inmunología , Antígenos CD8/genética , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/virología , Diferenciación Celular , Femenino , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Homeostasis/inmunología , Interferón-alfa/inmunología , Interferón gamma/inmunología , Interleucina-7/genética , Interleucina-7/inmunología , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Transducción de Señal , Fiebre del Nilo Occidental/inmunología , Fiebre del Nilo Occidental/patología , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/inmunología , Virus del Nilo Occidental/patogenicidadRESUMEN
IL-27 controls a diverse range of immune responses in many disease settings. Here, we identify intestinal epithelial cells (IECs) as one of the major IL-27 cellular sources in the gut-associated tissue. Unlike IL-27 secreted by innate immune cells, gut epithelial IL-27 is dispensable for T-bet+ regulatory T cell (T reg cell) differentiation or IL-10 induction. Rather, IEC-derived IL-27 specifically promotes a distinct CD8αα+CD4+ intraepithelial lymphocyte (IEL) population that acquires their functional differentiation at the intestinal epithelium. Loss of IL-27 in IECs leads to a selective defect in CD8αα+CD4+ IELs over time. Consequently, mice with IEC-specific IL-27 ablation exhibited elevated pathogen burden during parasitic infection, and this could be rescued by transfer of exogenous CD8αα+CD4+ IELs. Collectively, our data reveal that in addition to its known regulatory properties in preventing immune hyperactivity, gut epithelial IL-27 confers barrier immunity by inducing a specific IEL subset and further suggest that IL-27 produced by different cell types plays distinct roles in maintaining intestinal homeostasis.
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Células Epiteliales/inmunología , Interleucinas/inmunología , Mucosa Intestinal/inmunología , Linfocitos Intraepiteliales/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Diferenciación Celular/inmunología , Femenino , Homeostasis/inmunología , Masculino , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Transducción de Señal/inmunologíaRESUMEN
The CD8αß heterodimer plays a crucial role in the stabilization between major histocompatibility complex class I molecules (MHC-I) and the T cell receptor (TCR). The interaction between CD8 and MHC-I can be regulated by posttranslational modifications, which are proposed to play an important role in the development of CD8 T cells. One modification that has been proposed to control CD8 coreceptor function is ribosylation. Utilizing NAD+, the ecto-enzyme adenosine diphosphate (ADP) ribosyl transferase 2.2 (ART2.2) catalyzes the addition of ADP-ribosyl groups onto arginine residues of CD8α or ß chains and alters the interaction between the MHC and TCR complexes. To date, only interactions between modified CD8 and classical MHC-I (MHC-Ia), have been investigated and the interaction with non-classical MHC (MHC-Ib) has not been explored. Here, we show that ADP-ribosylation of CD8 facilitates the binding of the liver-restricted nonclassical MHC, H2-Q10, independent of the associated TCR or presented peptide, and propose that this highly regulated binding imposes an additional inhibitory leash on the activation of CD8-expressing cells in the presence of NAD+. These findings highlight additional important roles for nonclassical MHC-I in the regulation of immune responses.
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ADP-Ribosilación/inmunología , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Antígenos H-2/inmunología , Multimerización de Proteína/inmunología , ADP Ribosa Transferasas/genética , ADP Ribosa Transferasas/inmunología , ADP-Ribosilación/genética , Animales , Antígenos CD8/genética , Antígenos H-2/genética , Hígado/inmunología , Ratones , Ratones Noqueados , Multimerización de Proteína/genética , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunologíaRESUMEN
Background: The global outbreak of coronavirus disease 2019 (COVID-19) has turned into a worldwide public health crisis and caused more than 100,000,000 severe cases. Progressive lymphopenia, especially in T cells, was a prominent clinical feature of severe COVID-19. Activated HLA-DR+CD38+ CD8+ T cells were enriched over a prolonged period from the lymphopenia patients who died from Ebola and influenza infection and in severe patients infected with SARS-CoV-2. However, the CD38+HLA-DR+ CD8+ T population was reported to play contradictory roles in SARS-CoV-2 infection. Methods: A total of 42 COVID-19 patients, including 32 mild or moderate and 10 severe or critical cases, who received care at Beijing Ditan Hospital were recruited into this retrospective study. Blood samples were first collected within 3 days of the hospital admission and once every 3-7 days during hospitalization. The longitudinal flow cytometric data were examined during hospitalization. Moreover, we evaluated serum levels of 45 cytokines/chemokines/growth factors and 14 soluble checkpoints using Luminex multiplex assay longitudinally. Results: We revealed that the HLA-DR+CD38+ CD8+ T population was heterogeneous, and could be divided into two subsets with distinct characteristics: HLA-DR+CD38dim and HLA-DR+CD38hi. We observed a persistent accumulation of HLA-DR+CD38hi CD8+ T cells in severe COVID-19 patients. These HLA-DR+CD38hi CD8+ T cells were in a state of overactivation and consequent dysregulation manifested by expression of multiple inhibitory and stimulatory checkpoints, higher apoptotic sensitivity, impaired killing potential, and more exhausted transcriptional regulation compared to HLA-DR+CD38dim CD8+ T cells. Moreover, the clinical and laboratory data supported that only HLA-DR+CD38hi CD8+ T cells were associated with systemic inflammation, tissue injury, and immune disorders of severe COVID-19 patients. Conclusions: Our findings indicated that HLA-DR+CD38hi CD8+ T cells were correlated with disease severity of COVID-19 rather than HLA-DR+CD38dim population.
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Linfocitos T CD8-positivos/inmunología , COVID-19/inmunología , Enfermedades del Sistema Inmune/inmunología , SARS-CoV-2 , Adulto , Anciano , Antígenos CD8/inmunología , Citocinas/inmunología , Femenino , Antígenos HLA-DR/inmunología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
The intestinal epithelium is a unique tissue, serving both as a barrier against pathogens and to conduct the end digestion and adsorption of nutrients. As regards the former, the intestinal epithelium contains a diverse repertoire of immune cells, including a variety of resident lymphocytes, macrophages and dendritic cells. These cells serve a number of roles including mitigation of infection and to stimulate regeneration in response to damage. The transcription factor Cdx2, and to a lesser extent Cdx1, plays essential roles in intestinal homeostasis, and acts as a context-dependent tumour suppressor in colorectal cancer. Deletion of Cdx2 from the murine intestinal epithelium leads to macrophage infiltration resulting in a chronic inflammatory response. However the mechanisms by which Cdx2 loss evokes this response are poorly understood. To better understand this relationship, we used a conditional mouse model lacking all intestinal Cdx function to identify potential target genes which may contribute to this inflammatory phenotype. One such candidate encodes the histocompatability complex protein H2-T3, which functions to regulate intestinal iCD8α lymphocyte activity. We found that Cdx2 occupies the H3-T3 promoter in vivo and directly regulates its expression via a Cdx response element. Loss of Cdx function leads to a rapid and pronounced attenuation of H2-T3, followed by a decrease in iCD8α cell number, an increase in macrophage infiltration and activation of pro-inflammatory cascades. These findings suggest a previously unrecognized role for Cdx in intestinal homeostasis through H2-T3-dependent regulation of iCD8α cells.
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Antígenos CD8/inmunología , Factor de Transcripción CDX2/fisiología , Proteínas de Homeodominio/fisiología , Intestinos/inmunología , Linfocitos/inmunología , Macrófagos/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Animales , Diferenciación Celular , Intestinos/patología , Ratones , Ratones Noqueados , Regiones Promotoras Genéticas , Elementos de RespuestaRESUMEN
Determination of treatment response to immunotherapy in glioblastoma multiforme (GBM) is a process which can take months. Detection of CD8+ T cell recruitment to the tumor with a noninvasive imaging modality such as positron emission tomography (PET) may allow for tumor characterization and early evaluation of therapeutic response to immunotherapy. In this study, we utilized 89Zr-labeled anti-CD8 cys-diabody-PET to provide proof-of-concept to detect CD8+ T cell immune response to oncolytic herpes simplex virus (oHSV) M002 immunotherapy in a syngeneic GBM model. Immunocompetent mice (n = 16) were implanted intracranially with GSC005 GBM tumors, and treated with intratumoral injection of oHSV M002 or saline control. An additional non-tumor bearing cohort (n = 4) receiving oHSV M002 treatment was also evaluated. Mice were injected with 89Zr-labeled anti-CD8 cys-diabody seven days post oHSV administration and imaged with a preclinical PET scanner. Standardized uptake value (SUV) was quantified. Ex vivo tissue analyses included autoradiography and immunohistochemistry. PET imaging showed significantly higher SUV in tumors which had been treated with M002 compared to those without M002 treatment (p = 0.0207) and the non-tumor bearing M002 treated group (p = 0.0021). Accumulation in target areas, especially the spleen, was significantly reduced by blocking with the non-labeled diabody (p < 0.001). Radioactive probe accumulation in brains was consistent with CD8+ cell trafficking patterns after oHSV treatment. This PET imaging strategy could aid in distinguishing responders from non-responders during immunotherapy of GBM.
Asunto(s)
Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Glioma/terapia , Viroterapia Oncolítica/métodos , Animales , Antígenos CD8/antagonistas & inhibidores , Antígenos CD8/aislamiento & purificación , Linfocitos T CD8-positivos/virología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Glioma/diagnóstico por imagen , Glioma/inmunología , Glioma/virología , Humanos , Ratones , Radioisótopos/farmacología , Simplexvirus/genética , Tomografía Computarizada por Rayos X , Circonio/farmacologíaRESUMEN
Mycobacteriosis caused by Mycobacterium spp. causes economic damages to the world aquaculture industry. In mammals, mycolic acids contained in the cell wall of Mycobacterium spp. are presented by CD1b molecule as lipid antigens and induce cell-mediated immunity (CMI). Here, we investigated CMI responses against the mycolic acids of Mycobacterioides salmoniphilum in a CD1-lacking teleost fish, rainbow trout. After stimulation of trout leukocytes with mycolic acids, the number and percentage of CD8α+ T cells increased. Fish immunized with mycolic acids showed an up-regulation of IFN-γ. Further, in vitro re-stimulation of leukocytes derived from immunized fish resulted in proliferation of CD8α+ cells. These data suggest that mycolic acids are recognized as lipid antigens resulting in an activation of rainbow trout CD8α+ cells and up-regulation of the Th1 cytokine IFN-γ. The mycolic acids are promising candidates for vaccines to activate CD8α+ T cells against fish mycobacteriosis.
Asunto(s)
Inmunidad Celular , Mycobacteriaceae/inmunología , Ácidos Micólicos/inmunología , Oncorhynchus mykiss/inmunología , Animales , Antígenos Bacterianos/administración & dosificación , Antígenos Bacterianos/inmunología , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/inmunología , Antígenos CD8/inmunología , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/prevención & control , Memoria Inmunológica , Interferón gamma/genética , Interferón gamma/inmunología , Leucocitos/inmunología , Ácidos Micólicos/administración & dosificación , Oncorhynchus mykiss/microbiología , Linfocitos T/inmunología , Vacunación/veterinariaRESUMEN
Numerous studies reported a small subpopulation of TCRαß+CD4-CD8- (double-negative) T cells that exert regulatory functions in the peripheral lymphocyte population. However, the origin of these double-negative T (DNT) cells is controversial. Some researchers reported that DNT cells originated from the thymus, and others argued that these cells are derived from peripheral immune induction. We report a possible mechanism for the induction of nonregulatory CD4+ T cells to become regulatory double-negative T (iDNT) cells in vitro. We found that immature bone marrow dendritic cells (CD86+MHC-II- DCs), rather than mature DCs (CD86+MHC-II+), induced high levels of iDNT cells. The addition of an anti-MHC-II antibody to the CD86+MHC-II+ DC group significantly increased induction. These iDNT cells promoted B cell apoptosis and inhibited B cell proliferation and plasma cell formation. A subgroup of iDNT cells expressed NKG2D. Compared to NKG2D- iDNT cells, NKG2D+ iDNT cells released more granzyme B to enhance B cell regulation. This enhancement may function via NKG2D ligands expressed on B cells following lipopolysaccharide stimulation. These results demonstrate that MHC-II impedes induction, and iDNT cells may be MHC independent. NKG2D expression on iDNT cells enhanced the regulatory function of these cells. Our findings elucidate one possible mechanism of the induction of peripheral immune tolerance and provide a potential treatment for chronic allograft rejection in the future.
Asunto(s)
Linfocitos B/inmunología , Antígenos CD4/inmunología , Antígenos CD8/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Linfocitos T/inmunología , Animales , Antígeno B7-2/genética , Antígeno B7-2/inmunología , Antígeno B7-2/metabolismo , Antígenos CD4/genética , Antígenos CD4/metabolismo , Antígenos CD8/genética , Antígenos CD8/metabolismo , Células Cultivadas , Citocinas/genética , Citocinas/inmunología , Citocinas/metabolismo , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Expresión Génica/inmunología , Granzimas/genética , Granzimas/inmunología , Granzimas/metabolismo , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/inmunología , Antígenos de Histocompatibilidad Clase II/metabolismo , Masculino , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Inmunológicos , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Linfocitos T/metabolismoRESUMEN
The importance of the adaptive T cell response in the control and resolution of viral infection has been well established. However, the nature of T cell-mediated viral control mechanisms in life-threatening stages of COVID-19 has yet to be determined. The aim of the present study was to determine the function and phenotype of T cell populations associated with survival or death of patients with COVID-19 in intensive care as a result of phenotypic and functional profiling by mass cytometry. Increased frequencies of circulating, polyfunctional CD4+CXCR5+HLA-DR+ stem cell memory T cells (Tscms) and decreased proportions of granzyme B-expressing and perforin-expressing effector memory T cells were detected in recovered and deceased patients, respectively. The higher abundance of polyfunctional PD-L1+CXCR3+CD8+ effector T cells (Teffs), CXCR5+HLA-DR+ Tscms, and anti-nucleocapsid (anti-NC) cytokine-producing T cells permitted us to differentiate between recovered and deceased patients. The results from a principal component analysis show an imbalance in the T cell compartment that allowed for the separation of recovered and deceased patients. The paucity of circulating PD-L1+CXCR3+CD8+ Teffs and NC-specific CD8+ T cells accurately forecasts fatal disease outcome. This study provides insight into the nature of the T cell populations involved in the control of COVID-19 and therefore might impact T cell-based vaccine designs for this infectious disease.