RESUMEN
During acute viral infections, innate immune cells invade inflamed tissues and face hypoxic areas. Hypoxia-inducible factors (HIFs) adapt cellular responses towards these conditions. We wanted to investigate the effects of a loss of HIF-2α in macrophages during acute Friend murine leukemia retrovirus (FV) infection in C57BL/6 mice using a Cre/loxP system. Remarkably, mice with floxed Hif-2a (Hif-2afl; Hif-2a is also known as Epas1) did not show any signs of FV infection independent of Cre activity. This prevented a detailed analysis of the role of macrophage HIF-2α for FV infection but allowed us to study a model of unexpected FV resistance. Hif-2afl mice showed a significant decrease in the expression of the Atp6v1e2 gene encoding for the E2 subunit of the vacuolar H+-ATPase, which resulted in a decreased acidification of lysosomes and limited virus entry into the cell. These findings highlight that the insertion of loxP sites is not always without functional consequences and has established a phenotype in the floxed Hif-2a mouse, which is not only unexpected, but unwanted and is of relevance for the use of this mouse strain in (at least virus) experiments.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Virus de la Leucemia Murina de Friend , ATPasas de Translocación de Protón Vacuolares , Animales , Ratones , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Virus de la Leucemia Murina de Friend/genética , Lisosomas/metabolismo , Macrófagos/metabolismo , Macrófagos/virología , Macrófagos/inmunología , Ratones Endogámicos C57BL , Infecciones por Retroviridae/genética , Infecciones por Retroviridae/metabolismo , Infecciones por Retroviridae/virología , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/metabolismo , ATPasas de Translocación de Protón Vacuolares/metabolismo , ATPasas de Translocación de Protón Vacuolares/genéticaRESUMEN
Dendritic cells (DC) play a crucial role in generating and maintaining antiviral immunity. While DC are implicated in the antiviral defense by inducing T cell responses, they can also become infected by Cytomegalovirus (CMV). CMV is not only highly species-specific but also specialized in evading immune protection, and this specialization is in part due to characteristic genes encoded by a given virus. Here, we investigated whether rat CMV can infect XCR1+ DC and if infection of DC alters expression of cell surface markers and migration behavior. We demonstrate that wild-type RCMV and a mutant virus lacking the γ-chemokine ligand xcl1 (Δvxcl1 RCMV) infect splenic rat DC ex vivo and identify viral assembly compartments. Replication-competent RCMV reduced XCR1 and MHCII surface expression. Further, gene expression of infected DC was analyzed by bulk RNA-sequencing (RNA-Seq). RCMV infection reverted a state of DC activation that was induced by DC cultivation. On the functional level, we observed impaired chemotactic activity of infected XCR1+ DC compared to mock-treated cells. We therefore speculate that as a result of RCMV infection, DC exhibit diminished XCR1 expression and are thereby blocked from the lymphocyte crosstalk.
Asunto(s)
Infecciones por Citomegalovirus , Muromegalovirus , Ratas , Animales , Citomegalovirus/genética , Linfocitos T/metabolismo , Infecciones por Citomegalovirus/metabolismo , Células DendríticasRESUMEN
CD4+ T cells play an important role in immune responses against pathogens and cancer cells. Although their main task is to provide help to other effector immune cells, a growing number of infections and cancer entities have been described in which CD4+ T cells exhibit direct effector functions against infected or transformed cells. The most important cell type in this context are cytotoxic CD4+ T cells (CD4+ CTL). In infectious diseases anti-viral CD4+ CTL are mainly found in chronic viral infections. Here, they often compensate for incomplete or exhausted CD8+ CTL responses. The induction of CD4+ CTL is counter-regulated by Tregs, most likely because they can be dangerous inducers of immunopathology. In viral infections, CD4+ CTL often kill via the Fas/FasL pathway, but they can also facilitate the exocytosis pathway of killing. Thus, they are very important effectors to keep persistent virus in check and guarantee host survival. In contrast to viral infections CD4+ CTL attracted attention as direct anti-tumor effectors in solid cancers only recently. Anti-tumor CD4+ CTL are defined by the expression of cytolytic markers and have been detected within the lymphocyte infiltrates of different human cancers. They kill tumor cells in an antigen-specific MHC class II-restricted manner not only by cytolysis but also by release of IFNγ. Thus, CD4+ CTL are interesting tools for cure approaches in chronic viral infections and cancer, but their potential to induce immunopathology has to be carefully taken into consideration.
Asunto(s)
Neoplasias , Linfocitos T Citotóxicos , Humanos , Linfocitos T CD4-PositivosRESUMEN
Antiretroviral therapy (ART) transformed HIV from a life-threatening disease to a chronic condition. However, eliminating the virus remains an elusive therapy goal. For several decades, Friend virus (FV) infection serves as a murine model to study retrovirus immunity. Similar to HIV, FV persists at low levels in lymph nodes B cell follicles avoiding elimination by immune cells. Such immune-privileged reservoirs exclude cytotoxic T cells from entry. However, CXCR5+ T cells are permitted to traffic through germinal centers. This marker is predominantly expressed by CD4+ follicular helper T cells (Tfh). Therefore, we explored immunotherapy to induce cytotoxic Tfh, which are rarely found under physiological conditions. The TNF receptor family member CD137 was first identified as a promising target for cancer immunotherapy. We demonstrated that FV-infected mice treatment with αCD137 antibody resulted in an induction of the cytotoxic program in Tfh. The therapy significantly increased numbers of cytotoxic Tfh within B cell follicles and contributed to viral load reduction. Moreover, αCD137 antibody combined with ART delayed virus rebound upon treatment termination without disturbing the lymph node architecture or antibody responses. Thus, αCD137 antibody therapy might be a novel strategy to target the retroviral reservoir and an interesting approach for HIV cure research.
Asunto(s)
Infecciones por VIH , Células T Auxiliares Foliculares , Animales , Ratones , Retroviridae , Linfocitos B , Inmunoterapia , Linfocitos T Colaboradores-InductoresRESUMEN
Human cytomegalovirus (CMV) is a ubiquitously distributed pathogen whose rodent counterparts such as mouse and rat CMV serve as common infection models. Here, we conducted global proteome profiling of rat CMV-infected cells and uncovered a pronounced loss of the transcription factor STAT2, which is crucial for antiviral interferon signalling. Via deletion mutagenesis, we found that the viral protein E27 is required for CMV-induced STAT2 depletion. Cellular and in vitro analyses showed that E27 exploits host-cell Cullin4-RING ubiquitin ligase (CRL4) complexes to induce poly-ubiquitylation and proteasomal degradation of STAT2. Cryo-electron microscopy revealed how E27 mimics molecular surface properties of cellular CRL4 substrate receptors called DCAFs (DDB1- and Cullin4-associated factors), thereby displacing them from the catalytic core of CRL4. Moreover, structural analyses showed that E27 recruits STAT2 through a bipartite binding interface, which partially overlaps with the IRF9 binding site. Structure-based mutations in M27, the murine CMV homologue of E27, impair the interferon-suppressing capacity and virus replication in mouse models, supporting the conserved importance of DCAF mimicry for CMV immune evasion.
Asunto(s)
Infecciones por Citomegalovirus , Muromegalovirus , Animales , Humanos , Ratones , Ratas , Microscopía por Crioelectrón , Infecciones por Citomegalovirus/genética , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Interferones/metabolismo , Factor de Transcripción STAT2/genética , Factor de Transcripción STAT2/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Receptores de Interleucina-17/metabolismoRESUMEN
BACKGROUND: Friend virus (FV) is a complex of the Friend murine leukemia virus (F-MuLV) and the replication-defective, pathogenic spleen focus forming virus (SFFV). In the past, we used a fluorescently labeled F-MuLV to analyze FV target cells. To build on these findings, we have now created a double-labeled FV that contains a Katushka-labeled F-MuLV and an mTagBFP-labeled SFFV, which we have used to study the infection by the two individual viruses in the FV infection of highly susceptible BALB/c mice. RESULTS: Our data show that the target cells of SFFV largely mirror those of F-MuLV, with the highest virus loads in erythroblasts, B cells and myeloid cells. The early phase of infection was dominated by cells infected by either SFFV or F-MuLV, whereas double-infected cells became dominant later in the course of infection with increasing viral loads. In the late phase of infection, the frequency of double-infected cells was similarly high as the frequencies of SFFV or F-MuLV single-infected cells, and single- and double-infected cells outnumbered the uninfected cells in the most highly infected cell populations such as erythroblasts. FV and retroviruses in general have been shown to induce interleukin 10 (IL-10) as a means of suppressing immune responses. Interestingly, we found in infected IL-10-eGFP reporter mice that SFFV-infected cells contributed to the IL-10-producing cell pool much more significantly than F-MuLV-infected cells, suggesting that the truncated SFFV envelope protein gp55 might play a role in IL-10 induction. Even though BALB/c mice mount notoriously weak immune responses against FV, infection of mice with an ablation of IL-10 expression in T cells showed transiently lower viral loads and stronger T cell activation, suggesting that IL-10 induction by FV and by SFFV in particular may contribute to a suppressed immune response in BALB/c mice. CONCLUSION: Our data provide detailed information about both F-MuLV- and SFFV-infected cells during the course of FV infection in highly susceptible mice and imply that the pathogenic SFFV contributes to immune suppression.
Asunto(s)
Virus de la Leucemia Murina de Friend , Leucemia Experimental , Ratones , Animales , Virus Formadores de Foco en el Bazo , Interleucina-10 , Bazo , Ratones Endogámicos BALB C , InmunidadRESUMEN
Retroviral envelope (Env) proteins have long been recognized to exhibit immunosuppressive properties, which affect the CD8+ T-cell response to an infection but also to immunization. Interestingly, we previously showed in the Friend murine leukemia virus (F-MuLV) model that the surface Env protein gp70 also plays a role in immunosuppression, in addition to the immunosuppressive function attributed to the transmembrane Env protein. We now demonstrate that immunization with F-MuLV Env leads to a significant increase in interleukin-10 (IL-10)-producing CD4+ T cells and that the induction of CD8+ T-cell responses in the presence of Env is rescued if the capacity of CD4+ T cells to produce IL-10 is abrogated, indicating a mechanistic role of IL-10-producing CD4+ T cells in mediating the Env-induced suppression of CD8+ T-cell responses in Env co-immunization. We found that CD8+ T-cell responses against different immunogens are not all equally affected. On the other hand, suppression of immunity was observed not only in co-immunization experiments but also for immune control of subcutaneous tumor growth after an Env immunization. Finally, we show that suppression of CD8+ T cells by the surface Env protein is observed not only for Friend MuLV Env but also for the Env proteins of other gamma retroviruses. Taken together, our results show that IL-10-producing CD4+ T cells mechanistically underlie the Env-mediated suppression of CD8+ T-cell responses and suggest the presence of an immunosuppressive motif in the surface Env protein of gamma retroviruses.
Asunto(s)
Infecciones por Retroviridae , Vacunas Virales , Animales , Ratones , Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , Virus de la Leucemia Murina de Friend , Productos del Gen env , Terapia de Inmunosupresión , Interleucina-10 , Retroviridae , Proteínas de los Retroviridae , HumanosRESUMEN
OBJECTIVE: The growth of uterine leiomyomas is regulated by progesterone, although the underlying molecular mechanisms are not fully understood. METHODS: Primary leiomyoma cells were isolated by standard method from 16 samples of uterine leiomyoma tissue. Uterine leiomyoma explants and primary leiomyoma cell cultures were exposed to progesterone in concentrations of 0.01 µg/ml, 0.1 µg/ml and 1 µg/ml for 24 h. Cell apoptosis was assessed with Annexin V assays performed in cell cultures by flow cytometry. The expression of PR-A, PR-B, Ki67, Akt, ERK, PTEN and PPARγ mRNAs was estimated in cultured leiomyoma cells and tissue explants by real time RT-PCR. RESULTS: Treatment with progesterone promoted viability and proliferation of cultured leiomyoma cells in a dose-dependent manner. Low and high doses of progesterone decreased early apoptosis of leiomyoma cells. High concentrations of progesterone increased the number of living cells in Annexin V assays. High doses of progesterone increased the expression of Ki67 mRNA, while low doses increased the expression of PR-A mRNA in cultured leiomyoma cells and tissue explants. In cell cultures, low doses of progesterone increased the expression of PR-B mRNA and the expression of PTEN and PPARγ mRNAs in a dose-dependent manner. Exposure of leiomyoma tissue explants to progesterone led to increased expression of PR-B and ERK mRNAs in a dose-dependent manner. CONCLUSIONS: The effects of progesterone on the apoptosis and proliferation of leiomyoma cells was dose-dependent and different in cell cultures and leiomyoma explants, possibly as a result of impacts derived from the tumor microenvironment.
Asunto(s)
Leiomioma , Neoplasias Uterinas , Apoptosis , Técnicas de Cultivo de Célula , Proliferación Celular , Femenino , Humanos , Progesterona , Receptores de Progesterona , Microambiente Tumoral , Neoplasias Uterinas/tratamiento farmacológicoRESUMEN
Type I Interferons (IFNs), including numerous IFNα subtypes and IFNß, are key molecules during innate and adaptive immune responses against viral infections. These cytokines exert various non-redundant biological activities, although binding to the same receptor. Persistent viral infections are often characterized by increased IFN signatures implicating a potential role of type I IFNs in disease pathogenesis. Using the well-established Friend retrovirus (FV) mouse model, we compared the therapeutic efficacy of IFNα11 and IFNß in acute and chronic retroviral infection. We observed a strong antiviral activity of both IFNs during acute FV infection, whereas only IFNα11 and not IFNß could also control persistent FV infection. The therapeutic treatment with IFNα11 induced the expression of antiviral IFN-stimulated genes (ISG) and improved cytotoxic T cell responses. Finally, dysfunctional CD8+ T cells solely regained cytotoxicity after IFNα11 treatment. Our data provide evidence for opposing activities of type I IFNs during chronic retroviral infections. IFNß was shown to be involved in immune dysfunction in chronic infections, whereas IFNα11 had a strong antiviral potential and reactivated exhausted T cells during persistent retroviral infection. In contrast, during acute infection, both type I IFNs were able to efficiently suppress FV replication.
Asunto(s)
Antivirales/farmacología , Interferón-alfa/farmacología , Infecciones por Retroviridae/tratamiento farmacológico , Infecciones por Retroviridae/virología , Animales , Biomarcadores , Línea Celular , Citotoxicidad Inmunológica/efectos de los fármacos , Manejo de la Enfermedad , Modelos Animales de Enfermedad , Femenino , Virus de la Leucemia Murina de Friend/fisiología , Interacciones Huésped-Patógeno/inmunología , Factores Inmunológicos/farmacología , Interferón Tipo I/farmacología , Interferón beta/farmacología , Virus de la Leucemia Murina/fisiología , Linfocitos/inmunología , Linfocitos/metabolismo , Ratones , Infecciones por Retroviridae/inmunología , Resultado del Tratamiento , Carga Viral/efectos de los fármacos , Replicación Viral/efectos de los fármacosRESUMEN
Aging results in profound immune dysfunction, resulting in the decline of vaccine responsiveness previously attributed to irreversible defects in the immune system. In addition to increased interleukin-6 (IL-6), we found aged mice exhibit increased systemic IL-10 that requires forkhead box P3-negative (FoxP3-), but not FoxP3+, CD4+T cells. Most IL-10-producing cells manifested a T follicular helper (Tfh) phenotype and required the Tfh cytokines IL-6 and IL-21 for their accrual, so we refer to them as Tfh10 cells. IL-21 was also required to maintain normal serum levels of IL-6 and IL-10. Notably, antigen-specific Tfh10 cells arose after immunization of aged mice, and neutralization of IL-10 receptor signaling significantly restored Tfh-dependent antibody responses, whereas depletion of FoxP3+ regulatory and follicular regulatory cells did not. Thus, these data demonstrate that immune suppression with age is reversible and implicate Tfh10 cells as an intriguing link between "inflammaging" and impaired immune responses with age.
RESUMEN
In retroviral infections, different immunological mechanisms are involved in the development of a chronic infection. In the Friend virus (FV) model, regulatory T cells (Tregs) were found to induce CD8+ T cell dysfunction before viral clearance is achieved and thus contribute to viral chronicity. Although studied for decades, the exact suppressive mechanisms of Tregs in the FV model remain elusive and an unavailable therapeutic target. However, extracellular IL-2 and intracellular NF-κB signaling were shown to be important pathways for Treg expansion and activation. Therefore, we decided to focus on these two pathways to test therapeutic approaches inhibiting Treg activation during FV infection. In this study, we show that the inhibition of either IL-2 or the NF-κB subunit c-Rel, impaired Treg expansion and activation at 2 weeks post-FV infection. Total numbers of Tregs as well as activated Tregs were reduced in FV-infected mice after treatment with anti-IL-2 antibodies or the c-Rel blocking reagent pentoxifylline. Surprisingly, this did not affect the expansion or function of virus-specific CD8+ T cells nor viral loads in the spleen. However, our data suggest that neutralization of IL-2 as well as blocking c-Rel efficiently inhibits virus-induced Treg expansion.
Asunto(s)
Interleucina-2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-rel/antagonistas & inhibidores , Infecciones por Retroviridae/inmunología , Transducción de Señal/inmunología , Linfocitos T Reguladores/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Femenino , Virus de la Leucemia Murina de Friend , Interleucina-2/inmunología , Activación de Linfocitos/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Pentoxifilina/administración & dosificación , Proteínas Proto-Oncogénicas c-rel/metabolismo , Linfocitos T Reguladores/patología , Carga ViralRESUMEN
Clinical administration of Interferon α (IFNα) resulted in limited therapeutic success against some viral infections. Immune modulation of CD8+ T cell responses during IFNα therapy is believed to play a pivotal role in promoting viral clearance. However, these clinical studies primarily focused on IFNα subtype 2. To date, the immunomodulatory roles of the remaining 10-13 IFNα subtypes remains poorly understood, thereby precluding assessments of their potential for more effective treatments. Here, we report that virus-specific CD8+ T cell responses were influenced to various extents by individual IFNα subtypes. IFNα4, 6, and 9 had the strongest effects on CD8+ T cells, including antiproliferative effects, improved cytokine production and cytotoxicity. Interestingly, augmented cytokine responses were dependent on IFNα subtype stimulation of dendritic cells (DCs), while antiproliferative effects and cytotoxicity were mediated by IFNAR signaling in either CD8+ T cells or DCs. Thus, precise modulation of virus-specific CD8+ T cell responses may be feasible for specific antiviral immunotherapies through careful selection and administration of individual IFNα subtypes.
Asunto(s)
Linfocitos T CD8-positivos/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Interferón-alfa/farmacología , Replicación Viral/efectos de los fármacos , Animales , Antivirales/inmunología , Antivirales/farmacología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/virología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Citocinas/inmunología , Citocinas/metabolismo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Células Dendríticas/virología , Células HEK293 , Humanos , Factores Inmunológicos/inmunología , Factores Inmunológicos/farmacología , Interferón-alfa/clasificación , Interferón-alfa/inmunología , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Isoformas de Proteínas/inmunología , Isoformas de Proteínas/farmacología , Replicación Viral/inmunologíaRESUMEN
Immunization vectors based on cytomegalovirus (CMV) have attracted a lot of interest in recent years because of their high efficacy in the simian immunodeficiency virus (SIV) macaque model, which has been attributed to their ability to induce strong, unusually broad, and unconventionally restricted CD8+ T cell responses. To evaluate the ability of CMV-based vectors to mediate protection by other immune mechanisms, we evaluated a mouse CMV (MCMV)-based vector encoding Friend virus (FV) envelope (Env), which lacks any known CD8+ T cell epitopes, for its protective efficacy in the FV mouse model. When we immunized highly FV-susceptible mice with the Env-encoding MCMV vector (MCMV.env), we could detect high frequencies of Env-specific CD4+ T cells after a single immunization. While the control of an early FV challenge infection was highly variable, an FV infection applied later after immunization was tightly controlled by almost all immunized mice. Protection of mice correlated with their ability to mount a robust anamnestic neutralizing antibody response upon FV infection, but Env-specific CD4+ T cells also produced appreciable levels of interferon γ. Depletion and transfer experiments underlined the important role of antibodies for control of FV infection but also showed that while no Env-specific CD8+ T cells were induced by the MCMV.env vaccine, the presence of CD8+ T cells at the time of FV challenge was required. The immunity induced by MCMV.env immunization was long-lasting, but was restricted to MCMV naïve animals. Taken together, our results demonstrate a novel mode of action of a CMV-based vaccine for anti-retrovirus immunization that confers strong protection from retrovirus challenge, which is conferred by CD4+ T cells and antibodies.
Asunto(s)
Virus de la Leucemia Murina de Friend/inmunología , Muromegalovirus/inmunología , Vacunas Virales/inmunología , Traslado Adoptivo , Animales , Anticuerpos Antivirales/biosíntesis , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/virología , Femenino , Virus de la Leucemia Murina de Friend/genética , Virus de la Leucemia Murina de Friend/patogenicidad , Productos del Gen env/genética , Productos del Gen env/inmunología , Vectores Genéticos , Inmunización , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Muromegalovirus/genética , Infecciones por Retroviridae/inmunología , Infecciones por Retroviridae/prevención & control , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunología , Vacunas Virales/genéticaRESUMEN
B cell follicles of the spleen and lymph nodes are immune privileged sites and serve as sanctuaries for infected CD4+ cells in HIV infection. It is assumed that CD8+ T cell responses promote the establishment of the reservoir, as B cell follicles do not permit CD8+ T cell entry. Here we analyzed the infected cell population in the Friend retrovirus (FV) infection and investigated whether FV can similarly infect follicular cells. For analysis of FV-infected cells, we constructed a recombinant FV encoding the bright fluorescent protein mWasabi and performed flow cytometry with cells isolated from spleens, lymph nodes and bone marrow of FV-mWasabi-infected mice. Using t-stochastic neighbor embedding for data exploration, we demonstrate how the target cell population changes during the course of infection. While FV was widely distributed in erythrocytes, myeloid cells, B cells, and CD4+ T cells in the acute phase of infection, the bulk viral load in the late phase was carried by macrophages and follicular B and CD4+ T cells, suggesting that FV persists in cells that are protected from CD8+ T cell killing. Importantly, seeding into follicular cells was equally observed in CD8+ T cell-depleted mice and in highly FV-susceptible mice that mount a very weak immune response, demonstrating that infection of follicular cells is not driven by immune pressure. Our data demonstrate that infection of cells in the B cell follicle is a characteristic of the FV infection, making this murine retrovirus an even more valuable model for development of retrovirus immunotherapy approaches.IMPORTANCE Human immunodeficiency virus is notorious for its ability to avoid clearance by therapeutic interventions, which is partly attributed to the establishment of reservoirs in latently infected cells and cells that reside in immunologically privileged B cell follicles. In the work presented here, we show that cells of the B cell follicle are equally infected by a simple mouse gammaretrovirus. Using fluorescently labeled Friend retrovirus, we found that B cells and T cells in the B cell follicle, while not carrying the bulk of the virus load, were indeed infected by Friend virus in the early acute phase of the infection and persisted in the chronic infection. Our results suggest that infection of follicular cells may be a shared property of lymphotropic viruses and propose the FV infection of mice as a useful model to study strategies for follicular reservoir elimination.
Asunto(s)
Linfocitos B/virología , Virus de la Leucemia Murina de Friend/crecimiento & desarrollo , Leucemia Experimental/virología , Infecciones por Retroviridae/virología , Infecciones Tumorales por Virus/virología , Animales , Citometría de Flujo , Virus de la Leucemia Murina de Friend/genética , Proteínas Luminiscentes/análisis , Proteínas Luminiscentes/genética , Ganglios Linfáticos/virología , Ratones , Bazo/virología , Coloración y EtiquetadoRESUMEN
T cell responses are crucial for anti-tumor immunity. In chronic viral infections, anti-tumor T cell responses can be compromised due to various immunological mechanisms, including T cell exhaustion. To study mechanisms of anti-tumor immunity during a chronic viral infection, we made use of the well-established Friend virus (FV) mouse model. Chronically FV-infected mice are impaired in their ability to reject FBL-3 cells-a virus-induced tumor cell line of C57BL/6 origin. Here we aimed to explore therapeutic strategies to overcome the influence of T cell exhaustion during chronic viral infection, and reactivate effector CD8+ and CD4+ T cells to eliminate tumor cells. For T cell stimulation, agonistic antibodies against the tumor necrosis factor receptor (TNFR) superfamily members CD137 and CD134 were used, because they were reported to augment the cytotoxic program of T cells. αCD137 agonistic therapy, but not αCD134 agonistic therapy, resulted in FBL-3 tumor elimination in chronically FV-infected mice. CD137 stimulation significantly enhanced the cytotoxic activity of both CD4+ and CD8+ T cells, which were both required for efficient tumor control. Our study suggests that agonistic antibodies to CD137 can efficiently enhance anti-tumor immunity even in the setting of chronic viral infection, which might have promising therapeutic applications.
Asunto(s)
Vigilancia Inmunológica , Neoplasias Experimentales/inmunología , Infecciones por Retroviridae/inmunología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/agonistas , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Línea Celular Tumoral , Enfermedad Crónica , Citotoxicidad Inmunológica , Virus de la Leucemia Murina de Friend , Ratones , Ratones Endogámicos C57BL , Receptores OX40/agonistasRESUMEN
Natural killer (NK) cells play a key role in host defense against cancer and viral infections. It was shown that NK cells are important for the control of acute retroviral infections, but their antiviral activity depends on multiple parameters such as viral inoculation dose, interactions with myeloid cell types and the cytokine milieu. In addition, during an ongoing retroviral infection regulatory T cells (Tregs) can suppress NK cell functions. However, the precise role of Tregs on the initial NK cell response and their immediate antiviral activity after an acute retroviral infection is still unknown. Here we show that thymus-derived Tregs suppress the proliferation, effector functions and cytotoxicity of NK cells very early during acute Friend Retrovirus (FV) infection. Tregs exhibited an activated phenotype and increased the production of the immunosuppressive cytokines IL-10 and TGF-ß after FV infection of mice. Neutralization of the immunosuppressive cytokine IL-10 resulted in a significant augmentation of NK cell functions. Although the activation of dendritic cells (DCs) and macrophages as well as the IL-15 cytokine levels were increased after Treg depletion, Tregs mainly affect the NK cell activity in an IL-10-regulated pathway. In this study we demonstrate an IL-10-dependent suppression of NK cells by activated Tregs during the first days of a retroviral infection.
Asunto(s)
Virus de la Leucemia Murina de Friend/inmunología , Inmunidad Celular , Interleucina-10/inmunología , Células Asesinas Naturales/inmunología , Infecciones por Retroviridae/inmunología , Linfocitos T Reguladores/inmunología , Enfermedad Aguda , Animales , Células Dendríticas/inmunología , Células Dendríticas/patología , Femenino , Células Asesinas Naturales/patología , Masculino , Ratones , Infecciones por Retroviridae/patología , Linfocitos T Reguladores/patologíaRESUMEN
CD4+ helper T cells and cytotoxic CD8+ T cells are key players for adaptive immune responses against acute infections with retroviruses. Similar to textbook knowledge the most important function of CD4+ T cells during an acute retrovirus infection seems to be their helper function for other immune cells. Whereas there was no direct anti-viral activity of CD4+ T cells during acute Friend Virus (FV) infection, they were absolutely required for the control of chronic infection. During chronic FV infection a population of activated FV-specific CD4+ T cells did not express cytotoxic molecules, but Fas Ligand that can induce Fas-induced apoptosis in target cells. Using an MHC II-restricted in vivo CTL assay we demonstrated that FV-specific CD4+ T cells indeed mediated cytotoxic effects against FV epitope peptide loaded targets. CD4 + CTL killing was also detected in FV-infected granzyme B knockout mice confirming that the exocytosis pathway was not involved. However, killing could be blocked by antibodies against FasL, which identified the Fas/FasL pathway as critical cytotoxic mechanism during chronic FV infection. Interestingly, targeting the co-stimulatory receptor CD137 with an agonistic antibody enhanced CD4+ T cell cytotoxicity. This immunotherapy may be an interesting new approach for the treatment of chronic viral infections.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Citotoxicidad Inmunológica , Proteína Ligando Fas/inmunología , Leucemia Experimental/inmunología , Infecciones por Retroviridae/inmunología , Infecciones Tumorales por Virus/inmunología , Animales , Apoptosis , Células Cultivadas , Femenino , Virus de la Leucemia Murina de Friend/inmunología , Ratones , Ratones Endogámicos C57BLRESUMEN
Recent successes in immune therapeutic strategies aimed to improve control over tumor growth have sparked hope that long-lived control of cancer through stimulation of the immune system can be possible. However, the underlying immunological mechanisms that are induced by immunotherapeutic strategies are not well understood. In this study, we used the highly immunogenic Friend virus-induced FBL-3 tumor as a model to study the mechanisms of immunological tumor control by CD4(+) T cells in the course of CD137 (4-1BB) agonist immunotherapy in the absence of a CD8 T cell response. We demonstrate that treatment with a CD137 agonist resulted in complete FBL-3 tumor regression in CD8(+) T cell-deficient mice. CD137 signaling enhanced the production of proinflammatory cytokines and cytotoxic molecules in tumor-specific CD4(+) T cells. Interestingly, a subset of CD4(+)Foxp3(+) regulatory T cells was reprogrammed to eliminate immunogenic virus-induced tumor cells in response to CD137 agonist treatment. These cells expressed markers characteristic for Th cells (CD154) and produced the cytokine TNF-α or the T-box transcriptional factor Eomesodermin and granzyme B without loss of Foxp3 expression. Foxp3 Eomes double-positive CD4(+) T cells were capable of eliminating immunogenic virus-induced tumor cells in vivo. Thus, our data show that tumor-induced Foxp3(+)CD4(+) T cells can be reprogrammed into cytotoxic effector cells upon therapeutic costimulatory signaling and restore antitumor immunity.
Asunto(s)
Ligando 4-1BB/uso terapéutico , Neoplasias Experimentales/terapia , Linfocitos T Citotóxicos/inmunología , Linfocitos T Reguladores/inmunología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/agonistas , Animales , Ligando de CD40/metabolismo , Línea Celular Tumoral , Reprogramación Celular , Citocinas/inmunología , Factores de Transcripción Forkhead/biosíntesis , Granzimas/biosíntesis , Inmunoterapia , Depleción Linfocítica , Ratones , Ratones Noqueados , Proteínas de Dominio T Box/biosíntesis , Linfocitos T Reguladores/trasplante , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
PROBLEM: Recent studies showed the impairment of local cytokine balance in women with external endometriosis, but similar findings concerning direct production of cytokines by immunocompetent cells of women with adenomyosis are absent. In this context, investigation of the cytokine synthesis by mononuclear cells (MNCs) infiltrating eutopic and ectopic endometrium is of special interest. METHOD OF STUDY: Concentration of interferon-gamma (IFNgamma), interferon-alpha (IFNalpha), tumour necrosis factor-alpha (TNFalpha), interleukin- 1beta (IL-1beta) and epidermal growth factor (EGF) in supernatants (SNs) of 24-hr cultures of MNCs obtained from eutopic and ectopic endometrium of women with adenomyosis was determined by enzyme-linked immunosorbent assay. RESULTS: The levels of IFNgamma, IFNalpha, TNFalpha, IL-1beta and EGF in SNs of eutopic endometrial MNCs of women with adenomyosis were significantly increased and the content of IL-8 in SNs was reduced compared with that of the control figures. Ectopic MNCs of women with adenomyosis produced higher levels of IFNgamma, IFNalpha and TNFalpha than the MNCs of normal endometrium. The production of IL-1beta, IL-8 and EGF by ectopic endometrial MNCs was significantly reduced. CONCLUSION: The results obtained indicate a significant role of local cytokine production impairment in the development of adenomyosis.
Asunto(s)
Citocinas/metabolismo , Endometriosis/inmunología , Endometrio/inmunología , Estudios de Casos y Controles , Endometriosis/patología , Endometrio/patología , Factor de Crecimiento Epidérmico/metabolismo , Femenino , Humanos , Técnicas In Vitro , Interferón-alfa/metabolismo , Interferón gamma/metabolismo , Interleucina-1/metabolismo , Interleucina-8/metabolismo , Leucocitos Mononucleares/inmunología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The aim of our work was to establish the peculiarities of phenotype profile and functional activity of peritoneal immunocompetent cells of women with different rate of myoma growth. Forty three women with uterine myoma (main group) and 16 healthy women (control group) were recruited for study. According to the growth rate and tumor's size the main group was divided into two clinical subgroups: (1) women with stable small size of uterine myoma (23 patients), (2) women with large size rapidly growing myoma (20 patients). The expression of CD markers on the surface of peritoneal fluid (PF) lymphocytes and bactericidal and adhesive activity of macrophages were studied. It was found that in women with stable small myomas both lymphocytes and macrophages in PF were activated. In women with rapidly growing large myomas cellular reactions seemed to be inhibited and the impairment of maturation and differentiation of lymphocytes was observed. It can be suggested that local immune response is directly connected with the rate of myoma growth.