RESUMEN

MAGUK protein ZO-2 is present at tight junctions (TJs) and nuclei. In MDCK ZO-2 knockdown (KD) cells, nuclei exhibit an irregular shape with lobules and indentations. This condition correlates with an increase in DNA double strand breaks, however cells are not senescent and instead become resistant to UV-induced senescence. The irregular nuclear shape is also observed in isolated cells and in those without TJs, due to the lack of extracellular calcium. The aberrant nuclear shape of ZO-2 KD cells is not accompanied by a reduced expression of lamins A/C and B and lamin B receptors. Instead, it involves a decrease in constitutive and facultative heterochromatin, and microtubule instability that is restored with docetaxel. ZO-2 KD cells over-express SUN-1 that crosses the inner nuclear membrane and connects the nucleoskeleton of lamin A to nesprins, which traverse the outer nuclear membrane. Nesprins-3 and -4 that indirectly bind on their cytoplasmic face to vimentin and microtubules, respectively, are also over-expressed in ZO-2 KD cells, whereas vimentin is depleted. SUN-1 and lamin B1 co-immunoprecipitate with ZO-2, and SUN-1 associates to ZO-2 in a pull-down assay. Our results suggest that ZO-2 forms a complex with SUN-1 and lamin B1 at the inner nuclear membrane, and that ZO-2 and cell-cell contacts are required for a normal nuclear shape.

Asunto(s)

Comunicación Celular/inmunología , Epitelio/metabolismo , Proteína de la Zonula Occludens-2/metabolismo , Humanos , Transfección

RESUMEN

Gap junctions (GJs) are clusters of intercellular connexin-formed channels found at the plasma membrane that allow direct communication between the cytoplasm of adjacent cells. Numerous reports have described GJs as modulators of key immunological processes, including in anti-tumor immune responses. Here, we described a simple flow cytometry method to test in vitro antigen-dependent GJ-mediated cell-to-cell coupling between cytotoxic T cells and target melanoma cells.

Asunto(s)

Comunicación Celular/inmunología , Uniones Comunicantes/inmunología , Melanoma/inmunología , Linfocitos T Citotóxicos/inmunología , Uniones Comunicantes/patología , Humanos , Melanoma/patología , Linfocitos T Citotóxicos/patología

RESUMEN

New evidence suggests that glycan expression in placental cells of women with invasive disorders of pregnancy differs from that in normal pregnant women. Hypothesizing that modifications of glycan expression could account for the course of preeclampsia, we established placental villous histocultures and compared glycan expression in women with preeclampsia with that in normal pregnant women and also in syncytialized BeWo cells, and we tested the effect of glycan expression on the functional phenotypes of circulating natural killer (NK) cells. Histocultures of third-trimester placentae from women with preeclampsia and full-term placentae from healthy pregnant women and BeWo choriocarcinoma cells were assessed for the expression of terminal glycans by lectin-binding assays. Circulating NK cells from nonpregnant healthy donors were tested in vitro for their cytotoxic activity and intracellular cytokine content. Histocultures from women with preeclampsia expressed significantly more mannose than did those from healthy pregnant women. Both histocultures and BeWo cells expressed terminal fucose, mannose, sialic acid, and N -acetylgalactosamine, although mean fluorescence intensity (MFI) expression was lower in choriocarcinoma cells than in cells from histocultures. Cocultures of circulating NK cells with K562 target cells resulted in a dose-dependent cytotoxicity effect, but the use of BeWo cells as target reduced cytotoxic activity; this reduction was not affected by syncytialization. Histocultures of placental villous tissue of women with preeclampsia expressed high levels of terminal mannose. We proposethat placental glycans may modulate the functional activity of circulating NK cells in the context of systemic inflammatory response in preeclampsia.

Asunto(s)

Vellosidades Coriónicas/patología , Células Asesinas Naturales/inmunología , Polisacáridos/metabolismo , Preeclampsia/inmunología , Adolescente , Adulto , Estudios de Casos y Controles , Comunicación Celular/inmunología , Línea Celular , Vellosidades Coriónicas/inmunología , Vellosidades Coriónicas/metabolismo , Femenino , Glicosilación , Voluntarios Sanos , Humanos , Células Asesinas Naturales/metabolismo , Preeclampsia/sangre , Preeclampsia/patología , Embarazo , Tercer Trimestre del Embarazo , Estudios Prospectivos , Trofoblastos/inmunología , Trofoblastos/metabolismo , Adulto Joven

RESUMEN

Platelets are chief cells in hemostasis. Apart from their hemostatic roles, platelets are major inflammatory effector cells that can influence both innate and adaptive immune responses. Activated platelets have thromboinflammatory functions linking hemostatic and immune responses in several physiological and pathological conditions. Among many ways in which platelets exert these functions, platelet expression of pattern recognition receptors (PRRs), including TLR, Nod-like receptor, and C-type lectin receptor families, plays major roles in sensing and responding to pathogen-associated or damage-associated molecular patterns (PAMPs and DAMPs, respectively). In this review, an increasing body of evidence is compiled showing the participation of platelet innate immune receptors, including PRRs, in infectious diseases, sterile inflammation, and cancer. How platelet recognition of endogenous DAMPs participates in sterile inflammatory diseases and thrombosis is discussed. In addition, platelet recognition of both PAMPs and DAMPs initiates platelet-mediated inflammation and vascular thrombosis in infectious diseases, including viral, bacterial, and parasite infections. The study also focuses on the involvement of innate immune receptors in platelet activation during cancer, and their contribution to tumor microenvironment development and metastasis. Finally, how innate immune receptors participate in platelet communication with leukocytes, modulating leukocyte-mediated inflammation and immune functions, is highlighted. These cell communication processes, including platelet-induced release of neutrophil extracellular traps, platelet Ag presentation to T-cells and platelet modulation of monocyte cytokine secretion are discussed in the context of infectious and sterile diseases of major concern in human health, including cardiovascular diseases, dengue, HIV infection, sepsis, and cancer.

Asunto(s)

Presentación de Antígeno , Plaquetas/inmunología , Comunicación Celular/inmunología , Inmunidad Innata , Linfocitos T/inmunología , Trombosis/inmunología , Animales , Plaquetas/patología , Trampas Extracelulares/inmunología , Humanos , Receptores de Reconocimiento de Patrones/inmunología , Linfocitos T/patología , Trombosis/patología

RESUMEN

B-1 cells are a B-lymphocyte subtype whose roles in immunity are not completely defined. These cells can produce cytokines (mainly IL-10) and natural and specific antibodies. Currently, extracellular vesicles (EVs) released by immune cells have emerged as new important entities in cell-cell communication. Immune cells release EVs that can activate and/or modulate other immune cells. Here, we characterized the EVs released by peritoneal B-1 cells infected or not with Leishmania (Leishmania) amazonensis. This Leishmania species causes cutaneous leishmaniasis and can infect macrophages and B-1 cells. Our results showed that peritoneal B-1 cells spontaneously release EVs, but the parasite stimulated an increase in EVs production by peritoneal B-1 cells. The treatment of BALB/c and C57BL/6 bone marrow-derived macrophages (BMDM) with EVs from infected peritoneal B-1 cells led to differential expression of iNOS, IL-6, IL-10, and TNF-α. Additionally, BALB/c mice previous treated with EVs released by peritoneal B-1 cells showed a significant lower lesion size and parasite burden. Thus, this study demonstrated that peritoneal B-1 cells could release EVs that can alter the functions of macrophages in vitro and in vivo these EVs altered the course of L. amazonensis infection. These findings represent the first evidence that EVs from peritoneal B-1 cells can act as a new mechanism of cellular communication between macrophages and B-1 cells, contributing to immunity against experimental leishmaniasis.

Asunto(s)

Subgrupos de Linfocitos B/inmunología , Comunicación Celular/inmunología , Vesículas Extracelulares/inmunología , Leishmania/inmunología , Leishmaniasis/inmunología , Macrófagos Peritoneales/inmunología , Animales , Subgrupos de Linfocitos B/patología , Citocinas/inmunología , Vesículas Extracelulares/patología , Femenino , Leishmaniasis/patología , Macrófagos Peritoneales/patología , Ratones , Ratones Endogámicos BALB C , Óxido Nítrico Sintasa de Tipo II/inmunología

RESUMEN

Melanoma is a very lethal tumor type that easily spreads and colonizes regional and distant tissues. Crucial phenotypic changes that favor melanoma metastasis are interposed by the tumor microenvironment (TME), representing a complex network in which malignant cells communicate not only with each other but also with stromal and immune cells. This cell-cell communication can be mediated by extracellular vesicles (EVs), which are lipid bilayer-delimited particles capable of carrying a wide variety of bioactive compounds. Both melanoma-derived or TME-derived EVs deliver important pro- and antitumor signals implicated in various stages of tumor progression, such as proliferation, metastasis, and treatment response. In this review, we highlight the recent advances in EV-mediated crosstalk between melanoma and immune cells and other important cells of the TME, and address different aspects of this bidirectional interaction as well as how this may hinder or trigger the development and progression of melanoma. We also discuss the potential of using EVs as biomarkers and therapeutic strategies for melanoma.

Asunto(s)

Biomarcadores de Tumor/inmunología , Comunicación Celular/inmunología , Proliferación Celular , Vesículas Extracelulares/inmunología , Melanoma/inmunología , Microambiente Tumoral/inmunología , Vesículas Extracelulares/patología , Humanos , Melanoma/patología , Melanoma/terapia , Metástasis de la Neoplasia

RESUMEN

Neutrophil extracellular traps (NETs) emerge from the cell as a DNA scaffold associated with cytoplasmic and granular proteins, able to immobilize and kill pathogens. This association occurs following nuclear and granular membrane disintegration, allowing contact with the decondensed chromatin. Thus, it is reasonable to speculate that the DNA can also mix with miRNAs and carry them in NETs. Here, we report for the first time the presence of the miRNA carriers associated with NETs and miRNAs present in NET-enriched supernatants (NET-miRs), thus adding a novel class of molecules and new proteins that can be released and transported in the NET platform. We observed that the majority of NET-miRs were common to all four stimuli used (PMA, interleukin-8, amyloid fibrils and Leishmania), and that miRNA-142-3p carried by NETs down-modulates protein kinase Cα and regulates TNF-α production in macrophages upon NET interaction with these cells. Our findings unveil a novel role for NETs in the cell communication processes, allowing the conveyance of miRNA from neutrophils to neighboring cells.

Asunto(s)

Comunicación Celular/inmunología , Trampas Extracelulares/inmunología , MicroARNs/genética , Neutrófilos/inmunología , Factor de Necrosis Tumoral alfa/genética , Amiloide/farmacología , Antagomirs/genética , Antagomirs/metabolismo , Medios de Cultivo Condicionados/farmacología , Trampas Extracelulares/metabolismo , Regulación de la Expresión Génica , Humanos , Interleucina-8/farmacología , Leishmania braziliensis , MicroARNs/antagonistas & inhibidores , MicroARNs/inmunología , Neutrófilos/efectos de los fármacos , Neutrófilos/microbiología , Cultivo Primario de Células , Proteína Quinasa C-alfa/genética , Proteína Quinasa C-alfa/inmunología , Transducción de Señal , Células THP-1 , Acetato de Tetradecanoilforbol/farmacología , Factor de Necrosis Tumoral alfa/inmunología

RESUMEN

Activation of naive T cells by antigen-presenting cells (APCs) is an essential step in mounting an adaptive immune response. It is known that antigen recognition and T cell receptor (TCR) signaling depend on forces applied by the T cell actin cytoskeleton, but until recently, the underlying mechanisms have been poorly defined. Here, we review recent advances in the field, which show that specific actin-dependent structures contribute to the process in distinct ways. In essence, T cell priming involves a tug-of-war between the cytoskeletons of the T cell and the APC, where the actin cytoskeleton serves as a mechanical intermediate that integrates force-dependent signals. We consider each of the relevant actin-rich T cell structures separately and address how they work together at the topologically and temporally complex cell-cell interface. In addition, we address how this mechanobiology can be incorporated into canonical immunological models to improve how these models explain T cell sensitivity and antigenic specificity.

Asunto(s)

Citoesqueleto de Actina/genética , Actinas/genética , Células Presentadoras de Antígenos/inmunología , Sinapsis Inmunológicas/genética , Mecanotransducción Celular , Citoesqueleto de Actina/inmunología , Actinas/inmunología , Inmunidad Adaptativa/inmunología , Comunicación Celular/inmunología , Citoesqueleto/genética , Citoesqueleto/inmunología , Humanos , Sinapsis Inmunológicas/inmunología , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Modelos Inmunológicos , Seudópodos/inmunología , Seudópodos/ultraestructura , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Transducción de Señal/genética , Linfocitos T/inmunología

RESUMEN

Hemolytic uremic syndrome (HUS) is a consequence of Shiga toxin (Stx)-producing Escherichia coli (STEC) infection and is the most frequent cause of acute renal failure (ARF) in children. Subtilase cytotoxin (SubAB) has also been associated with HUS pathogenesis. We previously reported that Stx2 and SubAB cause different effects on co-cultures of human renal microvascular endothelial cells (HGEC) and human proximal tubular epithelial cells (HK-2) relative to HGEC and HK-2 monocultures. In this work we have analyzed the secretion of pro-inflammatory cytokines by co-cultures compared to monocultures exposed or not to Stx2, SubAB, and Stx2+SubAB. Under basal conditions, IL-6, IL-8 and TNF-α secretion was different between monocultures and co-cultures. After toxin treatments, high concentrations of Stx2 and SubAB decreased cytokine secretion by HGEC monocultures, but in contrast, low toxin concentrations increased their release. Toxins did not modulate the cytokine secretion by HK-2 monocultures, but increased their release in the HK-2 co-culture compartment. In addition, HK-2 monocultures were stimulated to release IL-8 after incubation with HGEC conditioned media. Finally, Stx2 and SubAB were detected in HGEC and HK-2 cells from the co-cultures. This work describes, for the first time, the inflammatory responses induced by Stx2 and SubAB, in a crosstalk model of renal endothelial and epithelial cells.

Asunto(s)

Citocinas/metabolismo , Células Endoteliales/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Proteínas de Escherichia coli/toxicidad , Túbulos Renales Proximales/efectos de los fármacos , Microvasos/efectos de los fármacos , Toxina Shiga II/toxicidad , Subtilisinas/toxicidad , Comunicación Celular/efectos de los fármacos , Comunicación Celular/inmunología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/inmunología , Células Cultivadas , Técnicas de Cocultivo , Sinergismo Farmacológico , Células Endoteliales/inmunología , Células Epiteliales/inmunología , Síndrome Hemolítico-Urémico , Humanos , Riñón/irrigación sanguínea

RESUMEN

Chagas disease is a lifelong pathology resulting from Trypanosoma cruzi infection. It represents one of the most frequent causes of heart failure and sudden death in Latin America. Herein, we provide evidence that aerobic glycolytic pathway activation in monocytes drives nitric oxide (NO) production, triggering tyrosine nitration (TN) on CD8+ T cells and dysfunction in patients with chronic Chagas disease. Monocytes from patients exhibited a higher frequency of hypoxia-inducible factor 1α and increased expression of its target genes/proteins. Nonclassical monocytes are expanded in patients' peripheral blood and represent an important source of NO. Monocytes entail CD8+ T cell surface nitration because both the frequency of nonclassical monocytes and that of NO-producing monocytes positively correlated with the percentage of TN+ lymphocytes. Inhibition of glycolysis in in vitro-infected peripheral blood mononuclear cells decreased the inflammatory properties of monocytes/macrophages, diminishing the frequency of IL-1ß- and NO-producing cells. In agreement, glycolysis inhibition reduced the percentage of TN+CD8+ T cells, improving their functionality. Altogether, these results clearly show that glycolysis governs oxidative stress on monocytes and modulates monocyte-T cell interplay in human chronic Chagas disease. Understanding the pathological immune mechanisms that sustain an inflammatory environment in human pathology is key to designing improved therapies.

Asunto(s)

Linfocitos T CD8-positivos/inmunología , Comunicación Celular/inmunología , Enfermedad de Chagas/inmunología , Glucólisis/inmunología , Monocitos/metabolismo , Trypanosoma cruzi/inmunología , Adulto , Animales , Linfocitos T CD8-positivos/efectos de los fármacos , Estudios de Casos y Controles , Comunicación Celular/efectos de los fármacos , Enfermedad de Chagas/sangre , Enfermedad de Chagas/tratamiento farmacológico , Chlorocebus aethiops , Técnicas de Cocultivo , Femenino , Glucólisis/efectos de los fármacos , Humanos , Activación de Linfocitos/efectos de los fármacos , Masculino , Persona de Mediana Edad , Monocitos/efectos de los fármacos , Monocitos/inmunología , Óxido Nítrico/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/inmunología , Cultivo Primario de Células , Proteínas Protozoarias/inmunología , Tirosina/metabolismo , Células Vero , Adulto Joven

RESUMEN

Brucella abortus is a stealthy intracellular bacterial pathogen of animals and humans. This bacterium promotes the premature cell death of neutrophils (PMN) and resists the killing action of these leukocytes. B. abortus-infected PMNs presented phosphatidylserine (PS) as "eat me" signal on the cell surface. This signal promoted direct contacts between PMNs and macrophages (Mϕs) and favored the phagocytosis of the infected dying PMNs. Once inside Mϕs, B. abortus replicated within Mϕs at significantly higher numbers than when Mϕs were infected with bacteria alone. The high levels of the regulatory IL-10 and the lower levels of proinflammatory TNF-α released by the B. abortus-PMN infected Mϕs, at the initial stages of the infection, suggested a non-phlogistic phagocytosis mechanism. Thereafter, the levels of proinflammatory cytokines increased in the B. abortus-PMN-infected Mϕs. Still, the efficient bacterial replication proceeded, regardless of the cytokine levels and Mϕ type. Blockage of PS with Annexin V on the surface of B. abortus-infected PMNs hindered their contact with Mϕs and hampered the association, internalization, and replication of B. abortus within these cells. We propose that B. abortus infected PMNs serve as "Trojan horse" vehicles for the efficient dispersion and replication of the bacterium within the host.

Asunto(s)

Brucella abortus/inmunología , Comunicación Celular/inmunología , Macrófagos/inmunología , Fagocitosis/inmunología , Animales , Brucella abortus/citología , Brucella abortus/fisiología , Brucelosis/inmunología , Brucelosis/metabolismo , Brucelosis/microbiología , Muerte Celular/inmunología , División Celular/inmunología , Interacciones Huésped-Patógeno/inmunología , Humanos , Mediadores de Inflamación/inmunología , Mediadores de Inflamación/metabolismo , Interleucina-10/inmunología , Interleucina-10/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiología , Neutrófilos/inmunología , Neutrófilos/microbiología , Fosfatidilserinas/inmunología , Fosfatidilserinas/metabolismo , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

The immune response has important roles in the biology of solid tumors, including oncogenesis, tumor growth, invasion and metastasis, and response to treatment. Improved understanding of tumor-immune system interactions has provided promising therapeutic options that are based on the rescue and enhancement of the anti-tumoral host response. Immune-based treatments have been approved for clinical use in various types of cancer, including head and neck cancer (HNC); other strategies involving combination therapies are currently in development. These novel therapies were developed based on knowledge derived from in vitro, in silico, and in vivo pre-clinical studies. However, clinical trials seldom replicate the efficacy observed in pre-clinical animal studies. This lack of correlation between pre-clinical studies and clinical trials may be related to limitations of the models used; which highlights the relevance of considering immune-related aspects of different pre-clinical models. Murine models are the most frequently used pre-clinical models of HNC and are discussed elsewhere. Non-murine models have characteristics that offer unique opportunities for the study of HNC etiology, therapeutic strategies, and tumor-immune system interactions. The current review focuses on immune-related aspects of non-murine models, including dog, cat, pig, zebrafish, and frog, that could be used to investigate tumor-immune interactions in HNC.

Asunto(s)

Comunicación Celular/inmunología , Modelos Animales de Enfermedad , Neoplasias de Cabeza y Cuello/inmunología , Neoplasias de Cabeza y Cuello/patología , Inmunidad Innata/fisiología , Animales , Anuros , Gatos , Perros , Ratones , Porcinos , Escape del Tumor/fisiología , Microambiente Tumoral/inmunología , Pez Cebra

RESUMEN

Characteristics of melanoma cells have been deciphered by studies carried out in two dimensional cell cultures growing as adherent monolayers on the bottom of plastic flasks. Melanoma cells can be cultured with a considerable degree of success, and, depending on the further use of the cells obtained in the culture, methodologies have to be adjusted to obtain reliable results. Although there are many melanoma continuous cell lines, in vitro 2D and 3D melanoma primary cell culture may be a more useful model to investigate interactions between cancer cells and immune system, as well as the effect of cytotoxic treatments and personalized medicine in environments more similar to the physiological conditions.Here, we described a protocol which employs many strategies to obtain primary 2D and 3D melanoma cultures as a model to study cell-cell and cell-microenvironment interactions that must be considered to properly design personalized cancer treatments, as well as for testing novel anticancer drugs and drug delivery vehicles.

Asunto(s)

Antineoplásicos/farmacología , Ensayos de Selección de Medicamentos Antitumorales/métodos , Melanoma/patología , Cultivo Primario de Células/métodos , Neoplasias Cutáneas/patología , Antineoplásicos/uso terapéutico , Biopsia , Comunicación Celular/efectos de los fármacos , Comunicación Celular/inmunología , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/inmunología , Ensayos de Selección de Medicamentos Antitumorales/instrumentación , Humanos , Melanoma/sangre , Melanoma/tratamiento farmacológico , Melanoma/inmunología , Cultivo Primario de Células/instrumentación , Neoplasias Cutáneas/sangre , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/inmunología , Manejo de Especímenes/instrumentación , Manejo de Especímenes/métodos , Esferoides Celulares , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/inmunología

RESUMEN

B lymphocytes are recognized for their crucial role in the adaptive immunity since they represent the only leukocyte lineage capable of differentiating into Ab-secreting cells. However, it has been demonstrated that these lymphocytes can exert several Ab-independent functions, including engulfing and processing Ags for presentation to T cells, secreting soluble mediators, providing co-stimulatory signals, and even participating in lymphoid tissues development. Beyond that, several reports claiming the existence of multiple B cell subsets contributing directly to innate immune responses have appeared. These "innate-like" B lymphocytes, whose phenotype, development pathways, tissue distribution, and functions are in most cases notoriously different from those of conventional B cells, are crucial to early protective responses against pathogens by exerting "crossover" defensive strategies that blur the established boundaries of innate and adaptive branches of immunity. Examples of these mechanisms include the rapid secretion of the polyspecific natural Abs, increased susceptibility to innate receptors-mediated activation, cytokine secretion, downstream priming of other innate cells, usage of specific variable immunoglobulin gene-segments, and other features. As these new insights emerge, it is becoming preponderant to redefine the functionality of B cells beyond their classical adaptive-immune tasks.

Asunto(s)

Anticuerpos/inmunología , Subgrupos de Linfocitos B/inmunología , Citocinas/inmunología , Inmunidad Celular , Inmunidad Humoral , Inmunidad Innata , Animales , Anticuerpos/genética , Antígenos CD/genética , Antígenos CD/inmunología , Subgrupos de Linfocitos B/clasificación , Subgrupos de Linfocitos B/citología , Comunicación Celular/inmunología , Linaje de la Célula/genética , Linaje de la Célula/inmunología , Citocinas/genética , Expresión Génica , Humanos

RESUMEN

Human T cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T cell leukemia/lymphoma. The development of HAM/TSP, a chronic neuroinflammatory disease, is correlated to complex interaction between the host immune response and the infecting virus. Tax expression plays an important role in HAM/TSP pathogenesis by activating various cellular genes, including the cytokines interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Exosomes have emerged as an important factor of cell-to-cell communication contributing to diverse cellular processes, including immune modulation. Considering the potential role of exosomes in modulating the immune response and inflammation, the main objective of this study was to examine if HTLV-1-infected cells produce exosomes carrying viral proteins or inflammatory molecules, which can participate in the chronic inflammation that is observed in patients with HAM/TSP. Exosomes were isolated from HTLV-1-infected cell line, evaluated for the tax mRNA presence, and tested for the ability to activate peripheral mononuclear cells (PBMC) in inducing an inflammatory immune response. We observed that the proinflammatory cytokines, IFN-γ and TNF-α, were upregulated in T cells after treatment of the PBMC with Tax-carrying exosomes compared to the negative control. Interleukin-4, Granzyme B, and Perforin did not show alterations. Taken together, these results suggest that exosomes carrying tax-mRNA isolated from HTLV-1-infected cells might induce the production of proinflammatory cytokines and activate T helper (Th)1, and not Th2-immune response. If this finding is further confirmed, this study may have impact on investigations on the pathogenesis of HAM-TSP and the inflammatory response involved in this disease.

Asunto(s)

Exosomas/metabolismo , Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/genética , Interferón gamma/metabolismo , Paraparesia Espástica Tropical/inmunología , ARN Mensajero/metabolismo , Adulto , Donantes de Sangre , Comunicación Celular/inmunología , Células Cultivadas , Exosomas/virología , Femenino , Sangre Fetal/citología , Humanos , Linfoma de Células T/patología , Linfoma de Células T/virología , Masculino , Paraparesia Espástica Tropical/virología , ARN Viral , Células TH1/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

Brucellosis is an infectious disease elicited by bacteria of the genus Brucella. Platelets have been extensively described as mediators of hemostasis and responsible for maintaining vascular integrity. Nevertheless, they have been recently involved in the modulation of innate and adaptive immune responses. Although many interactions have been described between Brucella abortus and monocytes/macrophages, the role of platelets during monocyte/macrophage infection by these bacteria remained unknown. The aim of this study was to investigate the role of platelets in the immune response against B. abortus. We first focused on the possible interactions between B. abortus and platelets. Bacteria were able to directly interact with platelets. Moreover, this interaction triggered platelet activation, measured as fibrinogen binding and P-selectin expression. We further investigated whether platelets were involved in Brucella-mediated monocyte/macrophage early infection. The presence of platelets promoted the invasion of monocytes/macrophages by B. abortus. Moreover, platelets established complexes with infected monocytes/macrophages as a result of a carrier function elicited by platelets. We also evaluated the ability of platelets to modulate functional aspects of monocytes in the context of the infection. The presence of platelets during monocyte infection enhanced IL-1ß, TNF-α, IL-8, and MCP-1 secretion while it inhibited the secretion of IL-10. At the same time, platelets increased the expression of CD54 (ICAM-1) and CD40. Furthermore, we showed that soluble factors released by B. abortus-activated platelets, such as soluble CD40L, platelet factor 4, platelet-activating factor, and thromboxane A2, were involved in CD54 induction. Overall, our results indicate that platelets can directly sense and react to B. abortus presence and modulate B. abortus-mediated infection of monocytes/macrophages increasing their pro-inflammatory capacity, which could promote the resolution of the infection.

Asunto(s)

Plaquetas/citología , Brucella abortus/fisiología , Comunicación Celular/inmunología , Monocitos/inmunología , Brucella abortus/inmunología , Antígeno CD56/inmunología , Línea Celular , Células Cultivadas , Quimiocina CCL2/inmunología , Humanos , Interleucina-10/inmunología , Interleucina-8/inmunología , Monocitos/microbiología , Células THP-1 , Factor de Necrosis Tumoral alfa/inmunología

RESUMEN

B-cells mediate humoral adaptive immune response via the production of antibodies and cytokines, and by inducing T-cell activation. These functions can be attributed to distinct B-cell subpopulations. Infection with Trypanosoma cruzi, the causative agent of Chagas disease, induces a polyclonal B-cell activation and lytic antibody production, critical for controlling parasitemia. Individuals within the chronic phase of Chagas disease may remain in an asymptomatic form (indeterminate), or develop severe cardiomyopathy (cardiac form) that can lead to death. Currently, there is no effective vaccine to prevent Chagas disease, and no treatment to halt the development of the cardiomyopathy once it is installed. The pathology associated with cardiac Chagas disease is a result of an inflammatory reaction. Thus, discovering characteristics of the host's immune response that favor the maintenance of favorable heart function may unveil important immunotherapeutic targets. Given the importance of B cells in antibody production and parasite control, we investigated T. cruzi-derived antigenic fractions responsible for B-cell activation and whether frequencies and functional characteristics of B-cell subpopulations are associated with different clinical outcomes of human Chagas disease. We stimulated cells from indeterminate (I) and cardiac (C) Chagas patients, as well as non-infected individuals (NI), with T. cruzi-derived protein- (PRO), glycolipid- (GCL) and lipid (LIP)-enriched fractions and determined functional characteristics of B-cell subpopulations. Our results showed that the frequency of B-cells was similar amongst groups. PRO, but not GCL nor LIP, led to an increased frequency of B1 B-cells in I, but not C nor NI. Although stimulation with PRO induced higher TNF expression by B1 B-cells from C and I, as compared to NI, it induced expression of IL-10 in cells from I, but not C. Stimulation with PRO induced an increased frequency of the CD11b+ B1 B-cell subpopulation, which was associated with better cardiac function. Chagas patients displayed increased IgM production, and activation of gamma-delta T-cells, which have been associated with B1 B-cell function. Our data showed that PRO activates CD11b+ B1 B-cells, and that this activation is associated with a beneficial clinical status. These findings may have implications in designing new strategies focusing on B-cell activation to prevent Chagas disease cardiomyopathy.

Asunto(s)

Antígenos de Protozoos/inmunología , Linfocitos B/inmunología , Cardiomiopatía Chagásica/inmunología , Proteínas Protozoarias/inmunología , Trypanosoma cruzi/inmunología , Adulto , Anciano , Antígenos de Protozoos/metabolismo , Linfocitos B/metabolismo , Brasil , Antígeno CD11b/inmunología , Antígeno CD11b/metabolismo , Comunicación Celular/inmunología , Células Cultivadas , Cardiomiopatía Chagásica/sangre , Cardiomiopatía Chagásica/parasitología , Estudios Transversales , Femenino , Glucolípidos/inmunología , Glucolípidos/metabolismo , Humanos , Inmunoglobulina M/inmunología , Inmunoglobulina M/metabolismo , Interleucina-10/inmunología , Interleucina-10/metabolismo , Linfocitos Intraepiteliales/inmunología , Linfocitos Intraepiteliales/metabolismo , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Cultivo Primario de Células , Proteínas Protozoarias/metabolismo , Trypanosoma cruzi/metabolismo , Adulto Joven

RESUMEN

T regulatory cells play a key role in the control of the immune response, both in health and during illness. While the mechanisms through which T regulatory cells exert their function have been extensively described, their molecular effects on effector cells have received little attention. Thus, this revision is aimed at summarizing our current knowledge on those regulation mechanisms on the target cells from a molecular perspective.

Asunto(s)

Inmunomodulación , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Animales , Comunicación Celular/inmunología , Citocinas/metabolismo , Citotoxicidad Inmunológica , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Granzimas/metabolismo , Humanos , Sistema Inmunológico/citología , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Inmunidad , Activación de Linfocitos/inmunología , Perforina/metabolismo , Transducción de Señal

RESUMEN

The expression of N-glycolyl-monosialodihexosyl-ganglioside (NGcGM3) in humans is restricted to cancer cells; therefore, it is a tumor antigen. There are measurable quantities of circulating anti-NGcGM3 antibodies (aNGcGM3 Abs) in human serum. Interestingly, some people have circulating Ag-specific immunoglobulins G (IgGs) that are capable of complement mediated cytotoxicity against NGcGM3 positive cells, which is relevant for tumor surveillance. In light of the chemical nature of Ag, we postulated it as a candidate ligand for CD1d. Furthermore, we hypothesize that the immune mechanism involved in the generation of these Abs entails cross talk between B lymphocytes (Bc) and invariant natural killer T cells (iNKT). Combining cellular techniques, such as flow cytometry and biochemical assays, we demonstrated that CD1d binds to NGcGM3 and that human Bc present NGcGM3 in a CD1d context according to two alternative strategies. We also showed that paraformaldehyde treatment of cells expressing CD1d affects the presentation. Finally, by co-culturing primary human Bc with iNKT and measuring Ki-67 expression, we detected a reproducible increment in the proliferation of the iNKT population when Ag was on the medium. Our findings identify a novel, endogenous, human CD1d ligand, which is sufficiently competent to stimulate iNKT. We postulate that CD1d-restricted Bc presentation of NGcGM3 drives effective iNKT activation, an immunological mechanism that has not been previously described for humans, which may contribute to understanding aNGcGM3 occurrence.

Asunto(s)

Antígenos CD1d/inmunología , Linfocitos B/inmunología , Comunicación Celular/inmunología , Gangliósido G(M3)/inmunología , Células T Asesinas Naturales/inmunología , Adulto , Presentación de Antígeno/inmunología , Antígenos CD1d/metabolismo , Linfocitos B/metabolismo , Línea Celular , Proliferación Celular , Células Cultivadas , Técnicas de Cocultivo , Citometría de Flujo , Gangliósido G(M3)/metabolismo , Humanos , Ligandos , Activación de Linfocitos/inmunología , Células T Asesinas Naturales/metabolismo , Tonsila Palatina/citología , Unión Proteica/inmunología

RESUMEN

Dendritic cells (DCs), the most important professional antigen-presenting cells (APC), play crucial role in both immunity and tolerance. It is well known that DCs are able to mount immune responses against foreign antigens and simultaneously tolerate self-antigens. Since DCs can be modulated depending on the surrounding microenvironment, they can act as a bridge between innate and adaptive immunity. However, the mechanisms that support this dual role are not entirely clear. Recent studies have shown that DCs can be manipulated ex vivo in order to trigger their tolerogenic profile, what can be a tool to be used in clinical trials aiming the treatment of various diseases and the prevention of transplant rejection. In this sense, the blockage of costimulatory molecules on DC, in the attempt of inhibiting the second signal in the immunological synapse, can be considered as one of the main strategies under development. This review brings an update on current therapies using tolerogenic dendritic cells modulated with costimulatory blockers with the aim of reducing transplant rejection. However, although there are current clinical trials using tolerogenic DC to treat allograft rejection, the actual challenge is to modulate these cells in order to maintain a permanent tolerogenic profile.

Asunto(s)

Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Tolerancia Inmunológica , Inmunología del Trasplante , Inmunidad Adaptativa , Animales , Comunicación Celular/inmunología , Rechazo de Injerto/inmunología , Rechazo de Injerto/terapia , Humanos , Inmunidad Innata , Inmunoterapia , Transducción de Señal , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Trasplante Homólogo