Dendritic Cells: Location, Function, and Clinical Implications

Dendritic cells (DCs) are antigen-presenting cells derived from bone marrow precursors and form a widely distributed cellular system throughout the body. DCs exert immune-surveillance for exogenous and endogenous antigens and the later activation of naive T lymphocytes giving rise to various immunological responses. Different growth factors and cytokines can modulate the differentiation and function of DCs, GM-CSF, M-CSF, Flt3, and TGF-β, resulting in a large variety of DCs with different functional abilities. Thus, DCs are classified as plasmacytoid DCs (pDCs), conventional DCs (cDCs), and DCs derived from monocytes (mDCs). Functionally, the cDCs may be divided into two states: immature and mature. Immature DCs are specialist in uptaking and processing antigens; in contrast, mature DCs are professional in antigen presentation. It has been observed that immature cDCs can induce immune tolerance while mature cDCs may induce Th2 or Th1 immune responses. It is worth noting that different subpopulations of DCs have the ability to secrete different cytokine patterns, resulting in the induction of different immunological responses. Furthermore DCs are involved in the pathophysiology of several diseases such as contact hypersensitivity, autoimmune diseases, or cancer, but they can also be used as therapeutic tools in these conditions

The frequency of defective genomes in Omicron differs from that of the Alpha, Beta and Delta variants

Evolution; Genetics; Molecular biologyEvolució; Genètica; Biologia molecularEvolución; Genética; Biología molecularThe SARS-CoV-2 Omicron variant emerged showing higher transmissibility and possibly higher resistance to current COVID-19 vaccines than other variants dominating the global pandemic. In March 2020 we performed a study in clinical samples, where we found that a portion of genomes in the SARS-CoV-2 viral population accumulated deletions immediately before the S1/S2 cleavage site (furin-like cleavage site, PRRAR/S) of the spike gene, generating a frameshift and appearance of a premature stop codon. The main aim of this study was to determine the frequency of defective deletions in prevalent variants from the first to sixth pandemic waves in our setting and discuss whether the differences observed might support epidemiological proposals. The complete SARS-CoV-2 spike gene was deeply studied by next-generation sequencing using the MiSeq platform. More than 90 million reads were obtained from respiratory swab specimens of 78 COVID-19 patients with mild infection caused by the predominant variants circulating in the Barcelona city area during the six pandemic waves: B.1.5, B.1.1, B.1.177, Alpha, Beta, Delta, and Omicron. The frequency of defective genomes found in variants dominating the first and second waves was similar to that seen in Omicron, but differed from the frequencies seen in the Alpha, Beta and Delta variants. The changing pattern of mutations seen in the various SARS-CoV-2 variants driving the pandemic waves over time can affect viral transmission and immune escape. Here we discuss the putative biological effects of defective deletions naturally occurring before the S1/S2 cleavage site during adaption of the virus to human infection.This study was partially supported by Pla Estratègic de Recerca i Innovació en Salut (PERIS) – Direcció General de Recerca i Innovació en Salut (DGRIS), Catalan Health Ministry, Generalitat de Catalunya; the Spanish Network for the Research in Infectious Diseases (REIPI RD16/0016/0003) from the European Regional Development Fund (ERDF); Centro para el Desarrollo Tecnológico Industrial (CDTI) from the Spanish Ministry of Economy and Business, grant number IDI-20200297; Grant PI19/00301 from Instituto de Salud Carlos III cofinanced by the European Regional Development Fund (ERDF), and Gilead’s biomedical research project GLD21/00006. We gratefully acknowledge the authors, originating and submitting laboratories of the sequences from GISAID’s EpiCov Database on which this research is based

Jak3 Is Involved in Dendritic Cell Maturation and CCR7-Dependent Migration

BACKGROUND: CCR7-mediated signalling is important for dendritic cell maturation and homing to the lymph nodes. We have previously demonstrated that Jak3 participates in the signalling pathway of CCR7 in T lymphocytes. METHODOLOGY AND PRINCIPAL FINDINGS: Here, we used Jak3(-/-) mice to analyze the role of Jak3 in CCR7-mediated dendritic cells migration and function. First, we found no differences in the generation of DCs from Jak3(-/-) bone marrow progenitors, when compared to wild type cells. However, phenotypic analysis of the bone marrow derived DCs obtained from Jak3(-/-) mice showed reduced expression of co-stimulatory molecules compared to wild type (Jak3(+/+)). In addition, when we analyzed the migration of Jak3(-/-) and Jak3(+/+) mature DCs in response to CCL19 and CCL21 chemokines, we found that the absence of Jak3 results in impaired chemotactic responses both in vitro and in vivo. Moreover, lymphocyte proliferation and contact hypersensitivity experiments showed that DC-mediated T lymphocyte activation is reduced in the absence of Jak3. CONCLUSION/SIGNIFICANCE: Altogether, our data provide strong evidence that Jak3 is important for DC maturation, migration and function, through a CCR7-mediated signalling pathway

A score model for the continuous grading of early allograft dysfunction severity

[EN] Early allograft dysfunction (EAD) dramatically influences graft and patient outcomes. A lack of consensus on an EAD definition hinders comparisons of liver transplant outcomes and management of recipients among and within centers. We sought to develop a model for the quantitative assessment of early allograft function [Model for Early Allograft Function Scoring (MEAF)] after transplantation. A retrospective study including 1026 consecutive liver transplants was performed for MEAF score development. Multivariate data analysis was used to select a small number of postoperative variables that adequately describe EAD. Then, the distribution of these variables was mathematically modeled to assign a score for each actual variable value. A model, based on easily obtainable clinical parameters (ie, alanine aminotransferase, international normalized ratio, and bilirubin) and scoring liver function from 0 to 10, was built. The MEAF score showed a significant association with patient and graft survival at 3-, 6- and 12-month follow-ups. Hepatic steatosis and age for donors; cold/warm ischemia times and postreperfusion syndrome for surgery; and intensive care unit and hospital stays, Model for End-Stage Liver Disease and Child-Pugh scores, body mass index, and fresh frozen plasma transfusions for recipients were factors associated significantly with EAD. The model was satisfactorily validated by its application to an independent set of 200 patients who underwent liver transplantation at a different center. In conclusion, a model for the quantitative assessment of EAD severity has been developed and validated for the first time. The MEAF provides a more accurate graft function assessment than current categorical classifications and may help clinicians to make early enough decisions on retransplantation benefits. Furthermore, the MEAF score is a predictor of recipient and graft survival.This work was supported by the Carlos III Institute of Health of the Spanish Ministry of Science and Innovation (PI11/02942). Agustin Lahoz is grateful for a Miguel Server contract (CP08/00125) from the Spanish Ministry of Science and Innovation/Carlos III Institute of HealthPareja, E.; Cortes, M.; Hervás-Marín, D.; Mir, J.; Valdivieso, A.; Castell, JV.; Lahoz Rodríguez, AG. (2015). A score model for the continuous grading of early allograft dysfunction severity. Liver Transplantation. 21(1):38-46. https://doi.org/10.1002/lt.23990384621

Cavernas, Ecosistemas del Mundo Subterraneo

Hoja de Mano que describe la exposición museográfica "Cavernas, Ecosistemas del Mundo Subterraneo" donde se ilustra los diferentes ecosistemas subterráneos del país. Contiene glosario

Cellulose-Chitosan-Nanohydroxyapatite Hybrid Composites by One-Pot Synthesis for Biomedical Applications

The development of organic–inorganic hybrid materials deserves special interest for bone tissue engineering applications, where materials must have properties that induce the survival and activation of cells derived from the mesenchyme. In this work, four bio-nanocomposites based on cellulose and variable content of chitosan, from 15 to 50 w% based on cellulose, with nanohydroxyapatite and β-Glycerophosphate as cross-linking agent were synthesized by simplified and low-energy-demanding solvent exchange method to determine the best ratio of chitosan to cellulose matrix. This study analyzes the metabolic activity and survival of human dermal fibroblast cells cultivated in four bio-nanocomposites based on cellulose and the variable content of chitosan. The biocompatibility was tested by the in vitro cytotoxicity assays Live/Dead and PrestoBlue. In addition, the composites were characterized by FTIR, XRD and SEM. The results have shown that the vibration bands of β-Glycerophosphate have prevailed over the other components bands, while new diffraction planes have emerged from the interaction between the cross-linking agent and the biopolymers. The bio-nanocomposite micrographs have shown no surface porosity as purposely designed. On the other hand, cell death and detachment were observed when the composites of 1 and 0.1 w/v% were used. However, the composite containing 10 w% chitosan, against the sum of cellulose and β-Glycerophosphate, has shown less cell death and detachment when used at 0.01 w/v%, making it suitable for more in vitro studies in bone tissue engineering, as a promising economical biomaterial

100 Años de Acción Pública

Este cuadernillo conmemora los 100 años de vigencia ininterrumpida en el ordenamiento jurídico colombiano de la Acción Pública de Inconstitucionalidad (A.P.) y destaca la gestión de un grupo de políticos, juristas y hombres de negocios integrantes de un partido político: La Unión Republicana. Sus ilustres personajes buscaron, a principios del siglo XX, promover la concertación, la búsqueda de la paz, el equilibrio de los poderes públicos, el buen gobierno y la civilidad; con la intención de arraigar nuevos hábitos y reglas en el quehacer político nacional

GK-1 Improves the Immune Response Induced by Bone Marrow Dendritic Cells Loaded with MAGE-AX in Mice with Melanoma

The aim of dendritic cell (DC) vaccination in cancer is to induce tumor-specific effector T cells that may reduce and control tumor mass. Immunostimulants that could drive a desired immune response are necessary to be found in order to generate a long lasting tumor immune response. GK-1 peptide, derived from Taenia crassiceps, induces not only increase in TNFα, IFNγ, and MCP-1 production in cocultures of DCs and T lymphocytes but also immunological protection against influenza virus. Moreover, the aim of this investigation is the use of GK-1 as a bone marrow DCs (BMDCs) immunostimulant targeted with MAGE antigen; thus, BMDC may be used as immunotherapy against murine melanoma. GK-1 induced in BMDCs a meaningful increment of CD86 and IL-12. In addition, the use of BMDCs TNFα/GK-1/MAGE-AX induced the highest survival and the smallest tumors in mice. Besides, the treatment helped to increase CD8 lymphocytes levels and to produce IFNγ in lymph nodes. Moreover, the histopathological analysis showed that BMDCs treated with GK-1/TNFα and loaded with MAGE-AX induced the apparition of more apoptotic and necrotic areas in tumors than in mice without treatment. These results highlight the properties of GK-1 as an immunostimulant of DCs and suggest as a potential candidate the use of this immunotherapy against cancer disease

Bioinformatic Tools for NGS-Based Metagenomics to Improve the Clinical Diagnosis of Emerging, Re-Emerging and New Viruses

Epidemics and pandemics have occurred since the beginning of time, resulting in millions of deaths. Many such disease outbreaks are caused by viruses. Some viruses, particularly RNA viruses, are characterized by their high genetic variability, and this can affect certain phenotypic features: tropism, antigenicity, and susceptibility to antiviral drugs, vaccines, and the host immune response. The best strategy to face the emergence of new infectious genomes is prompt identification. However, currently available diagnostic tests are often limited for detecting new agents. High-throughput next-generation sequencing technologies based on metagenomics may be the solution to detect new infectious genomes and properly diagnose certain diseases. Metagenomic techniques enable the identification and characterization of disease-causing agents, but they require a large amount of genetic material and involve complex bioinformatic analyses. A wide variety of analytical tools can be used in the quality control and pre-processing of metagenomic data, filtering of untargeted sequences, assembly and quality control of reads, and taxonomic profiling of sequences to identify new viruses and ones that have been sequenced and uploaded to dedicated databases. Although there have been huge advances in the field of metagenomics, there is still a lack of consensus about which of the various approaches should be used for specific data analysis tasks. In this review, we provide some background on the study of viral infections, describe the contribution of metagenomics to this field, and place special emphasis on the bioinformatic tools (with their capabilities and limitations) available for use in metagenomic analyses of viral pathogens