Prediction of MHC-peptide binding: a systematic and comprehensive overview

T cell immune responses are driven by the recognition of peptide antigens (T cell epitopes) that are bound to major histocompatibility complex (MHC) molecules. T cell epitope immunogenicity is thus contingent on several events, including appropriate and effective processing of the peptide from its protein source, stable peptide binding to the MHC molecule, and recognition of the MHC-bound peptide by the T cell receptor. Of these three hallmarks, MHC-peptide binding is the most selective event that determines T cell epitopes. Therefore, prediction of MHC-peptide binding constitutes the principal basis for anticipating potential T cell epitopes. The tremendous relevance of epitope identification in vaccine design and in the monitoring of T cell responses has spurred the development of many computational methods for predicting MHC-peptide binding that improve the efficiency and economics of T cell epitope identification. In this report, we will systematically examine the available methods for predicting MHC-peptide binding and discuss their most relevant advantages and drawbacks

Recognition of the ligand-type specificity of classical and non-classical MHC I proteins.

Functional characterization of proteins belonging to the MHC I superfamily involves knowing their cognate ligands, which can be peptides, lipids or none. However, the experimental identification of these ligands is not an easy task and generally requires some a priori knowledge of their chemical nature (ligand-type specificity). Here, we trained k-nearest neighbor and support vector machine classifiers that predict the ligand-type specificity MHC I proteins with great accuracy. Moreover, we applied these classifiers to human and mouse MHC I proteins of uncharacterized ligands, obtaining some results that can be instrumental to unravel the function of these proteins

Immune Tolerance in the Oral Mucosa

The oral mucosa is a site of intense immune activity, where a large variety of immune cells meet to provide a first line of defense against pathogenic organisms. Interestingly, the oral mucosa is exposed to a plethora of antigens from food and commensal bacteria that must be tolerated. The mechanisms that enable this tolerance are not yet fully defined. Many works have focused on active immune mechanisms involving dendritic and regulatory T cells. However, epithelial cells also make a major contribution to tolerance by influencing both innate and adaptive immunity. Therefore, the tolerogenic mechanisms concurring in the oral mucosa are intertwined. Here, we review them systematically, paying special attention to the role of oral epithelial cells

Cellular Integrin α5β1 and Exosomal ADAM17 Mediate the Binding and Uptake of Exosomes Produced by Colorectal Carcinoma Cells

Approximately 25% of colorectal cancer (CRC) patients develop peritoneal metastasis, a condition associated with a bleak prognosis. The CRC peritoneal dissemination cascade involves the shedding of cancer cells from the primary tumor, their transport through the peritoneal cavity, their adhesion to the peritoneal mesothelial cells (PMCs) that line all peritoneal organs, and invasion of cancer cells through this mesothelial cell barrier and underlying stroma to establish new metastatic foci. Exosomes produced by cancer cells have been shown to influence many processes related to cancer progression and metastasis. In epithelial ovarian cancer these extracellular vesicles (EVs) have been shown to favor different steps of the peritoneal dissemination cascade by changing the functional phenotype of cancer cells and PMCs. Little is currently known, however, about the roles played by exosomes in the pathogenesis and peritoneal metastasis cascade of CRC and especially about the molecules that mediate their interaction and uptake by target PMCs and tumor cells. We isolated exosomes by size−exclusion chromatography from CRC cells and performed cell-adhesion assays to immobilized exosomes in the presence of blocking antibodies against surface proteins and measured the uptake of fluorescently-labelled exosomes. We report here that the interaction between integrin α5β1 on CRC cells (and PMCs) and its ligand ADAM17 on exosomes mediated the binding and uptake of CRC-derived exosomes. Furthermore, this process was negatively regulated by the expression of tetraspanin CD9 on exosomes

Propuesta de mejora de la asignatura TFG del Grado en Nutrición Humana y Diétetica. Implantación de la prueba ECOE

Depto. de Farmacología y ToxicologíaFac. de MedicinaFALSEsubmitte

Metodología experimental aplicada a la Inmunología Molecular

El objetivo general del proyecto es aplicar un modelo pedagógico en el que participen los alumnos de manera activa y apliquen el método científico en base a los conocimientos que han adquirido, resolviendo y realizando un caso práctico en el laboratorio. Integra una estrategia didáctica que va a fomentar la participación activa del alumnado provocando un aprendizaje significativo, ya que el alumno tiene que resolver mediante el razonamiento un caso práctico y luego integrarlo en el laboratorio con el uso de una técnica ampliamente utilizada en Inmunología, como es la citometría de flujo.Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaFALSEInnovasubmitte

Caracterización molecular del gen E de la familia glicoproteína-P de Leishmania tropica

El objetivo de la presente tesis doctoral ha sido la caracterización molecular del gen ltrpgpe sobrexpresado en la línea de leishmania tropica resistente a 1 mm de metotrexato. el aislamiento del gen se realizo mediante rastreo de una genoteca del parasito resitente a metrotexato, usando una sonda especifica para el gen ltpgpe de l. tarentolae. se aisló un clon en el que se encontro un marco abierto de lectura que codificaba para una proteina de 1677 aminoácidos, con un peso molecular estimado de 186 kda. se encontró que el gen ltrpgpe mantenía homologia significativa con miembros de la superfamilia abc y que la máxima homologia era mantenida con glicoproteinas-p de l. tarentoale no relacionadas con fenotipo mdr. el gen fue localizado en un cromosoma de 1500 kb, organizado como un gen de copia única, detectando un polmorfismo en el locus que contiene al gen lrpgpe. el estudio de la funcionalidad del gen ltrpgpe fue llevado a cabo sobre los parásitos transfectados con el gen ltrpgpe y fue enfocado en primer lugar hacia un estudio del posible papel de la proteína en resistencia a fármacos. para ello se determinaron los índices de resistencia frente a una amplia variedad de compuestos. los resultados obtenidos mostraron que bajo las condiciones experimentales usadas el gen ltrpgpe confiere bajos niveles de resistencia a derivados de arsénico. en segundo lugar quisimos saber si el gen se encuentra modificando el ph citoplasmtico, papel que ha sido atribuido a otras glicoproteinas-p. se realizaron medidas de ph intracelular tanto en parásitos silvestres como trasfectados con el gen encontrando que el ph intracelular de leishmania tropica no se veia afectado por la sobreexpresion del gen itrpgpe. por ultimo se determino en los parásitos transfectados con el gen ltrpgpe el posible papel regulador atribuido a las glicoproteinas-p sobre la actividad de canales aniónicos activados por choque hipotónicoTesis Universidad de Granada. Facultad de Ciencia

RIAM-VASP Module Relays Integrin Complement Receptors in Outside-In Signaling Driving Particle Engulfment

The phagocytic integrins and complement receptors αMβ2/CR3 and αXβ2/CR4 are classically associated with the phagocytosis of iC3b-opsonized particles. The activation of this receptor is dependent on signals derived from other receptors (inside-out signaling) with the crucial involvement of the Rap1-RIAM-Talin-1 pathway. Here, we analyze the implication of RIAM and its binding partner VASP in the signaling events occurring downstream of β2 integrins (outside-in) during complement-mediated phagocytosis. To this end, we used HL-60 promyelocytic cell lines deficient in RIAM or VASP or overexpressing EGFP-tagged VASP to determine VASP dynamics at phagocytic cups. Our results indicate that RIAM-deficient HL-60 cells presented impaired particle internalization and altered integrin downstream signaling during complement-dependent phagocytosis. Similarly, VASP deficiency completely blocked phagocytosis, while VASP overexpression increased the random movement of phagocytic particles at the cell surface, with reduced internalization. Moreover, the recruitment of VASP to particle contact sites, amount of pSer157-VASP and formation of actin-rich phagocytic cups were dependent on RIAM expression. Our results suggested that RIAM worked as a relay for integrin complement receptors in outside-in signaling, coordinating integrin activation and cytoskeletal rearrangements via its interaction with VASP