CONICET | Buscador de Institutos y Recursos Humanos

Tacaribe virus (TCRV) is a nonpathogenic member of the New World (NW) arenavirus family where pathogenic viruses such as Junin virus (JUNV) are found. NW arenaviruses utilize the transferrin receptor 1 (TfR1) from their natural host but pathogenic virus also use the human. In contrast, although TCRV is capable of using TfR1 orthologs from other species cannot use hTfR1. The main goal of this work is to characterize TCRV entry and the role of the hTfR. We use CHO, TRVb (which luck endogenous TfR1) and TRVb1 cells (which stably express hTfR1). All cell lines were treated with different drugs: chlorpromazine (CZ), which inhibit the clathrin-dependent endocytosis; nystatin (NT) and methyl--cyclodextrin (MCD), which inhibits the cholesterol-dependent endocytosis and dynasore (DYN); which inhibit the dynamin II-dependent endocytosis. JUNV infection and FITC-cholera toxin were used as controls. Also, all cell lines were transfected with the wild type (wt) and dominant negative (dn) of: EPS15 (essential for clathin-dependent endocytosis), dynamin II, Rab5 and Rab7 (early and late endosome markers repectibly). After treatment with this drugs or transfections, cells were infected with TCRV (m.o.i.=2 and 0,2). We quantify viral production and percentage of infected cells. In CHO and TRVb cells, CZ and DYN inhibit both parameters (70%) and all dn presents a reduction of infected cells when compared to their wt (50%). In TRVb1 cells, on the other hand, only with MCD, DYN and its dn; a reduction of number of positive cells was found (up to 50%). All together, these results allow us to postulate that TCRV may present different entry pathways. In those cells not expressing hTfR1 it use a clathin-dependent endocytosis but in those cells expressing this receptor, the main pathway is clathrin-independent. All cell lines depend on dynamin II and use the Rab5 and Rab7 dependent endocytic pathway.