CONICET | Buscador de Institutos y Recursos Humanos

The cytotoxic CD8 T cell (CTL) mediated-immune response is crucialfor tumor immunotherapy and for protective immunity againstintracellular pathogens. Dendritic cells (DC) have the ability to internalizeand present exogenous antigens (Ag) bound to MHC I toactivate naïve CD8 T cells through a process known as cross-presentation.Subunit vaccines are often poorly immunogenic and adjuvantsare required to boost immunity. The complexity of antigencross-presentation pathways makes difficult to identify therapeutictargets that can act as adjuvants able to generate protective CTLresponses. We performed a high throughput screening of libraries ofdrugs approved by international agencies to identify compounds andmolecular pathways capable of enhancing Ag cross-presentation inDCs. For it, we developed a high-performance screening method byadapting the colorimetric B3Z presentation assay using JAWSII DCcell line and Ovalbumin (OVA) as Ag. After assayed 1760 drugs, wefound 1.1% of them increased OVA cross-presentation. We validatedthese hits and functional analogs by performing dose-responseassays with both JAWSII and GMCSF BMDCs. Almost all of hits arelysosomotropic drugs that could promote biomacromolecules accumulation.As lipid bodies (LB)-formation has been associated to DCscross-presentation ability, five hits were evaluated for LBs formationin JAWSII cells by fluorescence microscopy. We found that ToloniumChloride, Amodiaquine Dihydrochloride and Perhexiline Maleateincreased the amount of LBs per cell. None of these five drugs producedan important increase neither in the MHCI-surface expressionnor in the soluble OVA-endocytosis by JAWSII cells. In conclusion,we established a sensitive, fast and robust screening platform forcompounds-search capable of stimulating Ag cross-presentation inDCs. Although the mechanism of action of these drugs is still underinvestigation, our preliminary results indicate that it is likely relatedto lipid metabolism.

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