Study the pathogenicity of rabies virus variants in Brazil
"Study the pathogenicity of rabies virus variants in Brazil"
開催日時： 令和2年 2月 18日（火） 16：00 ～ 17：00
演者氏名： Jane Megid
演題： Study the pathogenicity of rabies virus variants in Brazil
概要： The main reservoirs of the rabies virus in nature are members of the Carnivora and Chiroptera orders. In Brazil rabies is still endemic due to Variant 2 (dog) and Variant 3 (bats) and the independent cycle has been identified in a range of species as Callithrix jacchus (marmoset), and Cerdocyon thous (fox). Characterization of RABV isolates is required to a better understanding of virus and host interaction. We first studied the immune response and N gene replication in mice infected with all the Brazilian variants where it was observed the different patterns of direct fluorescence and N gene quantification in the brain. All variants showed an up and downregulated expression levels for genes in different moments, been most predominant in the symptomatic phase of the disease (qRT-PCR). The second experimental work studied the gene expression profile through the quantification of total mRNA using the microarray in mice experimentally infected with a dog (variant 2 or V2) and bat (variant 3 or V3). The brains of mice were processed and analyzed by microarray using the Affymetrix GeneChip® Mouse Gene 2.0 ST (Affymetrix, USA). The results showed, at 5d, no differentially expressed genes (DEGs); at 10 days post-infection 120 DEGs in the asymptomatic phase of the infection resulting from variant 2 and absence of DEGs by Variant 3. The symptomatic phase presented higher number of up and downregulated genes in variant 2 compared to variant 3 infection. The comparison of DEGs in symptomatic phase, between variants 2 and 3, showed 24 DEGs being exclusive of variant 3, 18 evidenced only in variant 2, and two observed in both variants. The microarray analysis suggests that variants 2 and 3 of the rabies virus induce the activation of similar pathways, mainly those related to the immune system, innate immune response, and defense of the host, but activate at different levels and with different intensity. There are a large number of differentially expressed genes in this study that require more careful analysis and complementary studies to determine their real relevance. This study represents the first general analysis of gene expression using microarrays in the brain of animals inoculated with RABV variant 3.