Ligandos asociados a moléculas HLA de clase I en infecciones virales y trastornos autoinmunitarios

Las células T CD8+ identifican y eliminan células infectadas y tumorales através del reconocimiento específico de péptidos procedentes de proteínasintracelulares unidos a moléculas del complejo principal de histocompatibilidadhumano (HLA) de clase I. La presentación de estos ligandos peptídicos presentadospor las moléculas HLA de clase I es fundamental para el control de múltiplesinfecciones virales, y también se ha involucrado en enfermedades de carácterautoinmunitario como las espondiloartropatías. En este contexto, el extraordinariopolimorfismo existente en las moléculas HLA de clase I determina los ligandospeptídicos que se pueden unir a los diferentes subtipos, puesto que únicamenteaquellos ligandos que presenten los residuos adecuados en posiciones concretas, quepermiten la interacción con aminoácidos específicos de la molécula HLA, son capacesde unirse a cada subtipo de clase I particular..

Role of pulmonary surfactant protein Sp-C dimerization on membrane fragmentation: an emergent mechanism involved in lung defense and homeostasis

Surfactant protein C (SP-C) is a protein present in the pulmonary surfactant system that is involved in the biophysical properties of this lipoprotein complex, but it also has a role in lung defense and homeostasis. In this article, we propose that the link between both functions could rely on the ability of SP-C to induce fragmentation of phospholipid membranes and generate small vesicles that serve as support to present different ligands to cells in the lungs. Our results using bimolecular fluorescence complementation and tunable resistive pulse sensing setups suggest that SP-C oligomerization could be the triggering event that causes membrane budding and nanovesiculation. As shown by fluorescence microscopy and flow cytometry, these vesicles are differentially assimilated by alveolar macrophages and alveolar type II cells, indicating distinct roles of these alveoli-resident cells in the processing of the SP-C- induced vesicles and their cargo. These results depict a more accurate picture of the mechanisms of this protein, which could be relevant for the comprehension of pulmonary pathologies and the development of new therapeutic approaches