Avaliação da resposta imune inata após infecção pelo zika virus em macrófagos previamente infectados com dengue virus

Abstract

Dengue vIrus (DENV) is a RNA virus belonging to Flaviviridae family comprising four antigenic distinct sorotypes. Dengue is the main arthropod-transmitted virus in the world representing a worldwide public health problem, specially in Brazil, where in 2016 was also registered the greatest outbreak of Zika virus (ZIKV), which shares genomic and structural characteristics to DENV. DENV and ZIKV co-circulation is real in Brazil providing evidences of co-infection. The innate immune response against DENV and ZIKV is mediated by pattern recognition receptors that trigger intracellular signaling to antiviral or inflammatory responses. Regarding that, the main goal of this work is to better understand the innate immunity response to ZIKV by macrophages previously infected to DENV. To access this, bone marrow cells from C57BL/6 mice were derived to macrophages (BMDMs) that were confirmed by flow cytometry with more than 95% of the cells CD11b+. BMDMs were infected with the four serotypes of DENV independently for 12 hours following ZIKV infection for more 12 hours. Twenty-four hours post infection, macrophage activation markers CD80 and CD86 were accessed by flow cytometry and fluorescence microscopy. The pro-inflammatory or antiviral expression genes were evaluated by qPCR. IFN- presented to be down-regulated in all analyzed groups. It was not observed differences in CD80 or CD86 expression in ZIKV infected BMDMs previously infected with DENV excepted to serotype 4, where it was observed an augmentation of both activation markers. On the other hand, TNF- and IL-1 showed to be down-regulated when compared to non-infected or only DENV4 infected cells. With this decrease the increase in cell viability was observed in relation to the decrease in the production of the cytokine TNF-α. Bioinformatic analysis indicated a putative control of both cytokine expression by mmu-miR-181a-5p which is also up-regulated to innate immunity response. Further experiments will be conducted to evaluate this miRNA expression focusing on to understand the relationship between BMDM activation markers and TNF- or IL-1 modulation in DENV4 model of infection followed ZIKV infection.