Matías Ostrowski

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In multicellular organisms, communication between cells mainly involves the secretion of proteins that then bind to receptors on neighbouring cells. But another mode of intercellular communication - the release of membrane vesicles - has recently become the subject of increasing interest. Membrane vesicles are complex structures composed of a lipid bilayer(More)
Exosomes are secreted membrane vesicles that share structural and biochemical characteristics with intraluminal vesicles of multivesicular endosomes (MVEs). Exosomes could be involved in intercellular communication and in the pathogenesis of infectious and degenerative diseases. The molecular mechanisms of exosome biogenesis and secretion are, however,(More)
After infection of swine with porcine reproductive and respiratory syndrome virus (PRRSV), there is a rapid rise of PRRSV-specific nonneutralizing antibodies (NNA), while neutralizing antibodies (NA) are detectable not sooner than 3 weeks later. To characterize neutralizing epitopes, we selected phages from a 12-mer phage display library using anti-PRRSV(More)
During progression from single cancer cells to a tumor mass and metastases, tumor cells send signals that can subvert their tissue microenvironment. These signals involve soluble molecules and various extracellular vesicles, including a particular type termed exosomes. The specific roles of exosomes secreted in the tumor microenvironment, however, is(More)
Foot-and-mouth disease virus (FMDV) is a cytopathic virus that experimentally infects mice, inducing a thymus-independent neutralizing Ab response that rapidly clears the virus. In contrast, vaccination with UV-inactivated virus induces a typical thymus-dependent (TD) response. In this study we show that dendritic cells (DCs) are susceptible to infection(More)
Pathophysiological meaning and the mechanism of the formation of megamitochondria (MG) induced under physiological and pathological conditions remain obscure. We now provide evidence suggesting that the MG formation may be a prerequisite for free radical-mediated apoptosis. MG were detected in primary cultured rat hepatocytes, rat liver cell lines RL-34 and(More)
Infection of mice with cytopathic foot-and-mouth disease virus (FMDV) induces a rapid and specific thymus-independent (TI) neutralizing antibody response that promptly clears the virus. Herein, it is shown that FMDV-infected dendritic cells (DCs) directly stimulate splenic innate-like CD9(+) B lymphocytes to rapidly (3 days) produce neutralizing anti-FMDV(More)
Expression of non-self antigens by tumors can induce activation of T cells in vivo, although this activation can lead to either immunity or tolerance. CD8+ T-cell activation can be direct (if the tumor expresses MHC class I molecules) or indirect (after the capture and cross-presentation of tumor antigens by dendritic cells). The modes of tumor antigen(More)
The adaptive immune system is equipped to eliminate both tumors and pathogenic microorganisms. It requires a series of complex and coordinated signals to drive the activation, proliferation, and differentiation of appropriate T cell subsets. It is now established that changes in cellular activation are coupled to profound changes in cellular metabolism. In(More)
OBJECTIVES Glucose metabolism plays a fundamental role in supporting the growth, proliferation and effector functions of T cells. We investigated the impact of HIV infection on key processes that regulate glucose uptake and metabolism in primary CD4 and CD8 T cells. DESIGN AND METHODS Thirty-eight HIV-infected treatment-naive, 35 HIV+/combination(More)