Evaluation of the innate immune response of human PBMCs to Oropouche virus infection

Orientador: José Luiz Proença MódenaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Vírus Oropouche (OROV) são vírus emergente transmitidos por artrópodes que têm demonstrado grande potencial de disseminação e eficiência na transmissão. Fatores que facilitam sua dispersão incluem aumento da mobilidade e expansão dos sistemas de transporte, expansão da densidade populacional, e principalmente desmatamento de florestas e mudanças na vegetação onde circulam os vetores virais. Os principais sintomas apresentados pela febre do Oropouche são cefaleia, mialgia, artralgia e exantema. Existem ainda relatos de pacientes que apresentaram sintomas hemorrágicos, ou complicações neurológicas associados a detecção de OROV. A modulação da resposta de monócitos e células dendríticas no início da infecção são eventos patognomônicos chaves para a progressão da infecção e desenvolvimento de doenças agudas e manifestações clínicas tardias durante as infecções virais. Dessa forma, foi analisado nesse trabalho a capacidade de replicação e persistência de OROV em PBMCs humanas, e a modulação da resposta imune gerada por essas células in vitro. Foi observado aumento da expressão de interferons do tipo I do tipo II e aumento na expressão de ISGs importantes na resposta antiviral, associado à diminuição gradativa da detecção de RNA viral. Apesar da resposta imune inata aparentemente conter a infecção in vitro, foi observado por meio de RNA PrimeFlow e citometria de fluxo que genoma viral ainda pode ser encontrado no interior de monócitos e linfócitos em pequenas quantidades, indicando a possibilidade dessas células servirem como cavalo de troia em microambientes específicos. Além disso, como nesse estudo foram utilizadas PBMCs doadores saudáveis, não é improvável que OROV possa se replicar nessas células em casos de algum tipo de imunodeficiênciaAbstract: Oropouche virus is an emergent virus transmitted by arthropods that has been demonstrating a high potential of dissemination and transmission efficiency. Factors that facilitate its dispersion include increase in mobility, expansion of transport systems, expansion of population density, and mainly deforestation and changes in the vegetation where vectors of the virus circulate. The OROV fever major symptoms are headache, myalgia, arthralgia and exanthema. Also, there are reports of patients that showed hemorrhagic symptoms or neurological complications associated to OROV detection. The immune response modulated by monocytes and dendritic cells at the early moments of infection are patognomonic key events to the progression of the infection, and to the development of acute diseases and late clinical manifestations during viral infections. Thus, in this work, were analyzed the capacity of replication and persistence of OROV in human PBMCs, and the modulation of the immune response of these cells in vitro. It was observed an increase in the expression of type I and II Interferons (IFN), in addition to a decrease in viral RNA detection. Even though the innate immune response apparently contains the infection in vitro, it was observed, using RNA Prime Flow and flow cytometry techniques, that viral genome is still been found inside monocytes and lymphocytes in small quantities indicating the possibility of these cells serving as a trojan horse in specific microenvironments. In addition, once the cells used in these experiments were obtained from healthy donors, it is not unlikely that OROV can replicate in these cells in cases of some type of immunodeficiencyMestradoMicrobiologiaMestra em Genética e Biologia Molecular208/17Funcam

SARS-CoV-2 uses CD4 to infect T helper lymphocytes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS-CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.</p

SARS-CoV-2 uses CD4 to infect T helper lymphocytes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of a major global outbreak of respiratory tract disease known as Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 infects mainly lungs and may cause several immune-related complications, such as lymphocytopenia and cytokine storm, which are associated with the severity of the disease and predict mortality. The mechanism by which SARS-CoV-2 infection may result in immune system dysfunction is still not fully understood. Here, we show that SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in blood and bronchoalveolar lavage T helper cells of severe COVID-19 patients. We demonstrated that SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule, which in turn mediates the entry of SARS-CoV-2 in T helper cells. This leads to impaired CD4 T cell function and may cause cell death. SARS-CoV-2-infected T helper cells express higher levels of IL-10, which is associated with viral persistence and disease severity. Thus, CD4-mediated SARS-CoV-2 infection of T helper cells may contribute to a poor immune response in COVID-19 patients.</p

High-Quality Draft Genome Sequence of Pantanalinema sp. GBBB05, a Cyanobacterium From Cerrado Biome

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Oropouche Virus Infects, Persists and Induces IFN Response in Human Peripheral Blood Mononuclear Cells as Identified by RNA PrimeFlow™ and qRT-PCR Assays

Oropouche orthobunyavirus (OROV) is an emerging arbovirus with a high potential of dissemination in America. Little is known about the role of peripheral blood mononuclear cells (PBMC) response during OROV infection in humans. Thus, to evaluate human leukocytes susceptibility, permissiveness and immune response during OROV infection, we applied RNA hybridization, qRT-PCR and cell-based assays to quantify viral antigens, genome, antigenome and gene expression in different cells. First, we observed OROV replication in human leukocytes lineages as THP-1 monocytes, Jeko-1 B cells and Jurkat T cells. Interestingly, cell viability and viral particle detection are maintained in these cells, even after successive passages. PBMCs from healthy donors were susceptible but the infection was not productive, since neither antigenome nor infectious particle was found in the supernatant of infected PBMCs. In fact, only viral antigens and small quantities of OROV genome were detected at 24 hpi in lymphocytes, monocytes and CD11c+ cells. Finally, activation of the Interferon (IFN) response was essential to restrict OROV replication in human PBMCs. Increased expression of type I/III IFNs, ISGs and inflammatory cytokines was detected in the first 24 hpi and viral replication was re-established after blocking IFNAR or treating cells with glucocorticoid. Thus, in short, our results show OROV is able to infect and remain in low titers in human T cells, monocytes, DCs and B cells as a consequence of an effective IFN response after infection, indicating the possibility of leukocytes serving as a trojan horse in specific microenvironments during immunosuppression

Gas6 drives Zika virus-induced neurological complications in humans and congenital syndrome in immunocompetent mice

Zika virus (ZIKV) has the ability to cross placental and brain barriers, causing congenital malformations in neonates and neurological disorders in adults. However, the pathogenic mechanisms of ZIKV-induced neurological complications in adults and congenital malformations are still not fully understood. Gas6 is a soluble TAM receptor ligand able to promote flavivirus internalization and downregulation of immune responses. Here we demonstrate that there is a correlation between ZIKV neurological complications with higher Gas6 levels and the downregulation of genes associated with anti-viral response, as type I IFN due to Socs1 upregulation. Also, Gas6 gamma-carboxylation is essential for ZIKV invasion and replication in monocytes, the main source of this protein, which was inhibited by warfarin. Conversely, Gas6 facilitates ZIKV replication in adult immunocompetent mice and enabled susceptibility to transplacental infection. Our data indicate that ZIKV promotes the upregulation of its ligand Gas6, which contributes to viral infectivity and drives the development of severe adverse outcomes during ZIKV infection