RESUMEN
Anti-CTLA-4 mAb is efficacious in enhancing tumor immunity in humans. CTLA-4 is expressed by conventional T cells upon activation and by naturally occurring FOXP3+CD4+ Treg cells constitutively, raising a question of how anti-CTLA-4 mAb can differentially control these functionally opposing T cell populations in tumor immunity. Here we show that FOXP3high potently suppressive effector Treg cells were abundant in melanoma tissues, expressing CTLA-4 at higher levels than tumor-infiltrating CD8+ T cells. Upon in vitro tumor-antigen stimulation of peripheral blood mononuclear cells from healthy individuals or melanoma patients, Fc-region-modified anti-CTLA-4 mAb with high antibody-dependent cell-mediated cytotoxicity (ADCC) and cellular phagocytosis (ADCP) activity selectively depleted CTLA-4+FOXP3+ Treg cells and consequently expanded tumor-antigen-specific CD8+T cells. Importantly, the expansion occurred only when antigen stimulation was delayed several days from the antibody treatment to spare CTLA-4+ activated effector CD8+T cells from mAb-mediated killing. Similarly, in tumor-bearing mice, high-ADCC/ADCP anti-CTLA-4 mAb treatment with delayed tumor-antigen vaccination significantly prolonged their survival and markedly elevated cytokine production by tumor-infiltrating CD8+ T cells, whereas antibody treatment concurrent with vaccination did not. Anti-CTLA-4 mAb modified to exhibit a lesser or no Fc-binding activity failed to show such timing-dependent in vitro and in vivo immune enhancement. Thus, high ADCC anti-CTLA-4 mAb is able to selectively deplete effector Treg cells and evoke tumor immunity depending on the CTLA-4-expressing status of effector CD8+ T cells. These findings are instrumental in designing cancer immunotherapy with mAbs targeting the molecules commonly expressed by FOXP3+ Treg cells and tumor-reactive effector T cells.
Asunto(s)
Citotoxicidad Celular Dependiente de Anticuerpos/efectos de los fármacos , Antineoplásicos Inmunológicos/farmacología , Linfocitos T CD8-positivos/inmunología , Antígeno CTLA-4/antagonistas & inhibidores , Vacunas contra el Cáncer/farmacología , Neoplasias/inmunología , Linfocitos T Reguladores/metabolismo , Animales , Antineoplásicos Inmunológicos/inmunología , Antígeno CTLA-4/inmunología , Vacunas contra el Cáncer/inmunología , Humanos , Ratones , Ratones Endogámicos BALB C , Neoplasias/patologíaRESUMEN
PD-1 blockade is a cancer immunotherapy effective in various types of cancer. In a fraction of treated patients, however, it causes rapid cancer progression called hyperprogressive disease (HPD). With our observation of HPD in â¼10% of anti-PD-1 monoclonal antibody (mAb)-treated advanced gastric cancer (GC) patients, we explored how anti-PD-1 mAb caused HPD in these patients and how HPD could be treated and prevented. In the majority of GC patients, tumor-infiltrating FoxP3highCD45RA-CD4+ T cells [effector Treg (eTreg) cells], which were abundant and highly suppressive in tumors, expressed PD-1 at equivalent levels as tumor-infiltrating CD4+ or CD8+ effector/memory T cells and at much higher levels than circulating eTreg cells. Comparison of GC tissue samples before and after anti-PD-1 mAb therapy revealed that the treatment markedly increased tumor-infiltrating proliferative (Ki67+) eTreg cells in HPD patients, contrasting with their reduction in non-HPD patients. Functionally, circulating and tumor-infiltrating PD-1+ eTreg cells were highly activated, showing higher expression of CTLA-4 than PD-1- eTreg cells. PD-1 blockade significantly enhanced in vitro Treg cell suppressive activity. Similarly, in mice, genetic ablation or antibody-mediated blockade of PD-1 in Treg cells increased their proliferation and suppression of antitumor immune responses. Taken together, PD-1 blockade may facilitate the proliferation of highly suppressive PD-1+ eTreg cells in HPDs, resulting in inhibition of antitumor immunity. The presence of actively proliferating PD-1+ eTreg cells in tumors is therefore a reliable marker for HPD. Depletion of eTreg cells in tumor tissues would be effective in treating and preventing HPD in PD-1 blockade cancer immunotherapy.
Asunto(s)
Antineoplásicos Inmunológicos/efectos adversos , Nivolumab/efectos adversos , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Neoplasias Gástricas/inmunología , Linfocitos T Reguladores/efectos de los fármacos , Anciano , Animales , Antígeno CTLA-4/metabolismo , Progresión de la Enfermedad , Humanos , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Masculino , Ratones , Neoplasias Gástricas/tratamiento farmacológico , Linfocitos T Reguladores/metabolismoRESUMEN
Recently emerging evidence that the NF-κB family plays an important role in autoimmune disease has produced very broad and sometimes paradoxical conclusions. In the present study, we elucidated that the activation of RelA (p65) of NF-κB and IκB dissociation assumes a distinct role in experimental autoimmune encephalomyelitis (EAE) progression by altering IκB phosphorylation and/or degradation. In the present study of factors that govern EAE, the presence and immunoreactivity of nuclear RelA and phospho-IκB were recorded at the initiation and peak stage, and degradation of IκBα progressed rapidly at an early stage then stabilized during recovery. The immunoreactivity to RelA and phospho-IκB occurred mainly in inflammatory cells and microglial cells but only slightly in astrocytes. Subsequently, the blockade of IκB dissociation from NF-κB reduced the severity of disease by decreasing antigen-specific T cell response and production of IL-17 in EAE. Thus, blocking the dissociation of IκB from NF-κB can be utilized as a strategy to inhibit the NF-κB signal pathway thereby to reduce the initiation, progression, and severity of EAE.
Asunto(s)
Encéfalo/metabolismo , Encefalomielitis Autoinmune Experimental/metabolismo , Fosfoproteínas/metabolismo , Factor de Transcripción ReIA/metabolismo , Animales , Encefalomielitis Autoinmune Experimental/patología , Femenino , Quinasa I-kappa B , Proteínas I-kappa B/metabolismo , Ratones , Ratones Endogámicos C57BL , Fosforilación , Clorometilcetona de TosilfenilalanilaRESUMEN
This report addresses whether small molecules can deplete FoxP3-expressing regulatory T (T reg) cells, thereby augmenting antitumor immunity. Imatinib, a tyrosine kinase inhibitor of oncogenic BCR-ABL protein expressed by chronic myelogenous leukemia (CML) cells, possesses off-targets including LCK expressed in T cells. We showed that imatinib-treated CML patients in complete molecular remission (CMR) exhibited selective depletion of effector T reg (eT reg) cells and significant increase in effector/memory CD8+ T cells while non-CMR patients did not. Imatinib at CML-therapeutic concentrations indeed induced apoptosis specifically in eT reg cells and expanded tumor antigen-specific CD8+ T cells in vitro in healthy individuals and melanoma patients, and suppressed colon tumor growth in vivo in mice. Mechanistically, because of FoxP3-dependent much lower expression of LCK and ZAP-70 in T reg cells compared with other T cells, imatinib inhibition of LCK further reduced their TCR signal intensity, rendering them selectively susceptible to signal-deprived apoptotis. Taken together, eT reg cell depletion by imatinib is instrumental in evoking effective immune responses to various cancers.
Asunto(s)
Neoplasias del Colon/tratamiento farmacológico , Mesilato de Imatinib/uso terapéutico , Inmunidad/efectos de los fármacos , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Linfocitos T Reguladores/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Línea Celular Tumoral , Neoplasias del Colon/inmunología , Neoplasias del Colon/patología , Modelos Animales de Enfermedad , Femenino , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Humanos , Mesilato de Imatinib/farmacología , Leucemia Mielógena Crónica BCR-ABL Positiva/sangre , Leucemia Mielógena Crónica BCR-ABL Positiva/inmunología , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/antagonistas & inhibidores , Ratones , Ratones Endogámicos BALB C , Ratones SCID , Ratones Transgénicos , Inhibidores de Proteínas Quinasas/farmacología , Receptores de Antígenos de Linfocitos T/antagonistas & inhibidores , Linfocitos T Reguladores/inmunología , Resultado del TratamientoRESUMEN
Bearing pathologic and clinical similarities to human multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE) is used as a murine model to test potential therapeutic agents for MS. Recently, we reported the protective effects of an acidic polysaccharide of Panax ginseng (APG) in C57BL/6 strain-dependent EAE, a model of primary progressive MS. In this study, we extend our previous findings on the therapeutic capacity of APG in relapsing-remitting EAE (rr-EAE), the animal model to closely mimic recurrent inflammatory demyelination lesions of relapsing-remitting MS. Treatments with APG led to a significant reduction of clinical symptoms and the relapse rate of EAE than vehicle treatments. Consistent with this, histological examination revealed that APG markedly modulated the infiltration of CD4[Formula: see text] T cells and CD11b[Formula: see text] macrophages into the spinal cord and the APG-treated CNS was devoid of demyelination and axonal damages. In addition, APG decreased the proliferation of peripheral PLP-reactive T cells and the production of pro-inflammatory factors such as IFN-[Formula: see text], IL-17 and TNF-[Formula: see text]. The fact that APG can induce clinically beneficial effects to distinct types of EAE furthers our understanding on the basis of its immunosuppression in EAE and, possibly, in MS. Our results suggest that APG may serve as a new therapeutic agent for MS as well as other human autoimmune diseases, and warrants continued evaluation for its translation into therapeutic application.
Asunto(s)
Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Panax/química , Fitoterapia , Polisacáridos/farmacología , Polisacáridos/uso terapéutico , Animales , Antígeno CD11b , Linfocitos T CD4-Positivos/inmunología , Células Cultivadas , Enfermedades Desmielinizantes , Modelos Animales de Enfermedad , Femenino , Humanos , Macrófagos/inmunología , Ratones Endogámicos C57BL , Esclerosis Múltiple/tratamiento farmacológico , Polisacáridos/aislamiento & purificación , Recurrencia , Médula Espinal/inmunología , Médula Espinal/patologíaRESUMEN
Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease in the murine central nervous system (CNS) and recapitulates the clinical and pathological features of human multiple sclerosis (MS). Glutamate carboxipeptidase II (GCPII), an enzyme expressed exclusively on astrocytes, is known to affect the disease progression of various neurological disorders by producing glutamate. Despite several findings indicating possible link between glutamate and MS/EAE, however, the involvement of astrocyte or GCPII on glutamate excitotoxicity has not received much attention in MS/EAE. When we examined GCPII expression during EAE progression in this study, we observed significantly elevated GCPII expression in peak stage of disease localized mainly in astrocytes. Intrigued by these results, we tried a potent GCPII inhibitor, 2-phosphonomethyl pentanedioic acid (2-PMPA), on EAE mice and noticed markedly attenuated EAE clinical signs along with significantly inhibited infiltration of inflammatory cells into CNS. Furthermore, 2-PMPA dampened the function of Th1 cell lineage and down-regulated mGluR1 expression in both periphery and CNS contributing to glutamate-mediated immune regulation. Our observations identify a sequence of events triggering EAE through GCPII overexpression, which may offer a novel therapeutic approach to the treatment of MS.
Asunto(s)
Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/enzimología , Glutamato Carboxipeptidasa II/antagonistas & inhibidores , Compuestos Organofosforados/farmacología , Aminoácidos/farmacología , Animales , Astrocitos/efectos de los fármacos , Astrocitos/enzimología , Progresión de la Enfermedad , Encefalomielitis Autoinmune Experimental/inmunología , Antagonistas de Aminoácidos Excitadores/farmacología , Femenino , Glutamato Carboxipeptidasa II/metabolismo , Ácido Glutámico/metabolismo , Humanos , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Inhibidores de Proteasas/farmacología , Ratas Endogámicas Lew , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Receptores de Glutamato Metabotrópico/metabolismo , Médula Espinal/efectos de los fármacos , Médula Espinal/enzimología , Médula Espinal/inmunología , Células TH1/efectos de los fármacos , Células TH1/inmunología , Xantenos/farmacologíaRESUMEN
Immunological tolerance to self requires naturally occurring regulatory T (Treg) cells. Yet how they stably control autoimmune T cells remains obscure. Here, we show that Treg cells can render self-reactive human CD8(+) T cells anergic (i.e., hypoproliferative and cytokine hypoproducing upon antigen restimulation) in vitro, likely by controlling the costimulatory function of antigen-presenting cells. Anergic T cells were naïve in phenotype, lower than activated T cells in T cell receptor affinity for cognate antigen, and expressed several coinhibitory molecules, including cytotoxic T lymphocyte-associated antigen-4 (CTLA-4). Using these criteria, we detected in healthy individuals anergic T cells reactive with a skin antigen targeted in the autoimmune disease vitiligo. Collectively, our results suggest that Treg cell-mediated induction of anergy in autoimmune T cells is important for maintaining self-tolerance.
Asunto(s)
Enfermedades Autoinmunes/inmunología , Linfocitos T CD8-positivos/inmunología , Anergia Clonal , Autotolerancia , Linfocitos T Reguladores/inmunología , Células Presentadoras de Antígenos/inmunología , Antígeno CTLA-4 , Humanos , Activación de Linfocitos , Receptores de Antígenos de Linfocitos T/inmunología , Vitíligo/inmunologíaRESUMEN
Owing to its susceptibility to radiation, the small intestine of mice is valuable for studying radioprotective effects. When exposed to radiation, intestinal crypt cells immediately go through apoptosis, which impairs swift differentiation necessary for the regeneration of intestinal villi. Our previous studies have elucidated that acidic polysaccharide of Panax ginseng (APG) protects the mouse small intestine from radiation-induced damage by lengthening villi with proliferation and repopulation of crypt cells. In the present study, we identified the molecular mechanism involved. C57BL/6 mice were irradiated with gamma-rays with or without APG and the expression levels of apoptosis-related molecules in the jejunum were investigated using immunohistochemistry. APG pretreatment strongly decreased the radiation-induced apoptosis in the jejunum. It increased the expression levels of anti-apoptotic proteins (Bcl-2 and Bcl-XS/L) and dramatically reduced the expression levels of pro-apoptotic proteins (p53, BAX, cytochrome c and caspase-3). Therefore, APG attenuated the apoptosis through the intrinsic pathway, which is controlled by p53 and Bcl-2 family members. Results presented in this study suggest that APG protects the mouse small intestine from irradiation-induced apoptosis through inhibition of the p53-dependent pathway and the mitochondria/caspase pathway. Thus, APG may be a potential agent for preventing radiation induced injuries in intestinal cells during radio-therapy such as in cancer treatment.
Asunto(s)
Apoptosis , Yeyuno/efectos de los fármacos , Extractos Vegetales/farmacología , Polisacáridos/farmacología , Traumatismos Experimentales por Radiación/tratamiento farmacológico , Protectores contra Radiación/farmacología , Animales , Proteínas Reguladoras de la Apoptosis/metabolismo , Caspasa 3/metabolismo , Femenino , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efectos de la radiación , Yeyuno/patología , Yeyuno/efectos de la radiación , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Mitocondrias/efectos de la radiación , Panax/química , Extractos Vegetales/uso terapéutico , Polisacáridos/uso terapéutico , Traumatismos Experimentales por Radiación/patología , Tolerancia a Radiación/efectos de los fármacos , Protectores contra Radiación/uso terapéuticoRESUMEN
Phloroglucinol (PG) is a phenolic compound isolated from Ecklonia cava, a brown algae abundant on Jeju island, Korea. Previous reports have suggested that PG exerts antioxidative and cytoprotective effects against oxidative stress. In this study, we confirmed that PG protected against small intestinal damage caused by ionizing radiation, and we investigated its protective mechanism in detail. Regeneration of intestinal crypts in the PG-treated irradiated group was significantly promoted compared with that in irradiated controls. The expression level of proapoptotic molecules such as p53, Bax, and Bak in the small intestine was downregulated and that of antiapoptotic molecules such as Bcl-2 and Bcl-X(S/L) was augmented in the PG-treated group. On histological observation of the small intestine, PG inhibited the immunoreactivity of p53, Bax, and Bak and increased that of Bcl-2 and Bcl-X(S/L). These results demonstrate the protective mechanisms of PG in mice against intestinal damage from ionizing radiation, providing the benefit of raising the apoptosis threshold of jejunal crypt cells.
Asunto(s)
Antioxidantes/farmacología , Proteínas Reguladoras de la Apoptosis/metabolismo , Apoptosis/efectos de los fármacos , Intestino Delgado/efectos de los fármacos , Floroglucinol/farmacología , Traumatismos Experimentales por Radiación/prevención & control , Animales , Antioxidantes/uso terapéutico , Citoprotección , Rayos gamma/efectos adversos , Inmunohistoquímica , Intestino Delgado/patología , Intestino Delgado/efectos de la radiación , Ratones , Ratones Endogámicos C57BL , Floroglucinol/uso terapéutico , Traumatismos Experimentales por Radiación/metabolismo , Traumatismos Experimentales por Radiación/patología , Células Madre/efectos de los fármacos , Células Madre/patologíaRESUMEN
Gamma ray irradiation triggers DNA damage and apoptosis of proliferating stem cells and peripheral immune cells, resulting in the destruction of intestinal crypts and lymphoid system. Geraniin is a natural compound extracts from an aquatic plant Nymphaea tetragona and possesses good antioxidant property. In this study, we demonstrate that geraniin rescues radiosensitive splenocytes and jejunal crypt cells from radiation-induced DNA damage and apoptosis. Isolated splenocytes from C57BL/6 mice treated with geraniin were protected against radiation injury of 2 Gy irradiation through the enhancement of the proliferation and attenuation of DNA damage. Also, geraniin inhibited apoptosis in radiosensitive splenocytes by reducing the expression level and immunoreactivity of proapoptotic p53 and Bax and increasing those of anti-apoptotic Bcl-2. In mice exposed to radiation, geraniin treatment protected splenocytes and intestinal crypt cells from radiation-induced cell death. Our results suggest that geraniin presents radioprotective effects by regulating DNA damage on splenocytes, exerting immunostimulatory capacities and inhibiting apoptosis of radiosensitive immune cells and jejunal crypt cells. Therefore, geraniin can be a radioprotective agent against γ-irradiation exposure.
Asunto(s)
Apoptosis/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Glucósidos/farmacología , Taninos Hidrolizables/farmacología , Protectores contra Radiación/farmacología , Animales , Apoptosis/efectos de la radiación , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Células Cultivadas , Daño del ADN/efectos de la radiación , Rayos gamma , Genes p53 , Glucósidos/administración & dosificación , Glucósidos/toxicidad , Taninos Hidrolizables/administración & dosificación , Taninos Hidrolizables/toxicidad , Inyecciones Intraperitoneales , Intestino Delgado/efectos de los fármacos , Intestino Delgado/patología , Intestino Delgado/efectos de la radiación , Yeyuno/citología , Yeyuno/efectos de los fármacos , Yeyuno/efectos de la radiación , Ratones , Ratones Endogámicos C57BL , Nymphaea/química , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Radiación Ionizante , Bazo/citología , Bazo/efectos de los fármacos , Bazo/patología , Pruebas de Toxicidad Aguda , Irradiación Corporal Total , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Vanadium, an essential micronutrient, has been implicated in controlling diabetes and carcinogenesis and in impeding reactive oxygen species (ROS) generation. γ-ray irradiation triggers DNA damage by inducing ROS production and causes diminution in radiosensitive immunocytes. In this study, we elucidate the immune activation capacities of Jeju water containing vanadium on immunosuppression caused by γ-ray irradiation, and identify its mechanism using various low doses of NaVO(3). We examined the intracellular ROS generation, DNA damage, cell proliferation, population of splenocytes, and cytokine/antibody profiles in irradiated mice drinking Jeju water for 180 days and in non-irradiated and in irradiated splenocytes both of which were treated with NaVO(3). Both Jeju water and 0.245 µM NaVO(3) attenuated the intracellular ROS generation and DNA damage in splenocytes against γ-ray irradiation. Splenocytes were significantly proliferated by the long-term intake of Jeju water and by 0.245 µM NaVO(3) treatment, and the expansion of B cells accounted for the increased number of splenocytes. Also, 0.245 µM NaVO(3) treatment showed the potency to amplify the production of IFN-γ and total IgG in irradiated splenocytes, which correlated with the expansion of B cells. Collectively, Jeju water containing vanadium possesses the immune activation property against damages caused by γ-irradiation.
Asunto(s)
Agua Subterránea/análisis , Bazo/inmunología , Bazo/efectos de la radiación , Vanadio/efectos adversos , Vanadio/análisis , Animales , Formación de Anticuerpos/efectos de los fármacos , Linfocitos B/efectos de los fármacos , Linfocitos B/efectos de la radiación , Radioisótopos de Cobalto , Colorantes , Ensayo Cometa , Citocinas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Fluoresceínas , Depuradores de Radicales Libres , Rayos gamma , Interferón gamma/biosíntesis , Ratones , Especies Reactivas de Oxígeno/metabolismo , República de Corea , Bazo/citología , Sales de Tetrazolio , Tiazoles , Timidina/metabolismo , Vanadatos/farmacologíaRESUMEN
An acidic polysaccharide of Panax ginseng (APG), so called ginsan, is a purified polysaccharide. APG has multiple immunomodulatory effects of stimulating natural killer (NK) and T cells and producing a variety of cytokines that proved to diminish the proinflammatory response, and protect from septic lethality. To determine APG's role in the autoimmune demyelinating disease, we tested whether APG can regulate inflammatory and encephalitogenic response in experimental autoimmune encephalomyelitis (EAE), an animal model of human multiple sclerosis (MS). Here, we demonstrate the therapeutic efficacy of the APG which induces the suppression of an encephalitogenic response during EAE. APG significantly ameliorates the progression of EAE by inhibiting the proliferation of autoreactive T cells and the production of inflammatory cytokines such as IFN-γ, IL-1ß and IL-17. More importantly, APG promotes the generation of immunosuppressive regulatory T cells (Tregs) through the activation of transcription factor, Foxp3. Furthermore, the depletion of CD25+ cells from APG-treated EAE mice abrogates the beneficial effects of EAE. The capacity of APG to induce clinically beneficial effects furthers our understanding of the basis for its therapeutic immunosuppression of EAE and, possibly, MS. Thus, our results suggest that APG may serve as an effective therapy for MS and other autoimmune diseases.