Identification of antigen cross-presentation potentiating drugs for vaccine development

Congreso; Reunión de Sociedades de Biociencias 2021; 2021

The cytotoxic CD8 T cell (CTL) mediated-immune response is crucial for tumor immunotherapy and for protective immunity against intracellular pathogens. Dendritic cells (DC) have the ability to internalize and present exogenous antigens (Ag) bound to MHC I to activate naïve CD8 T cells through a process known as cross-presentation. Subunit vaccines are often poorly immunogenic and adjuvants are required to boost immunity. The complexity of antigen cross-presentation pathways makes difficult to identify therapeutic targets that can act as adjuvants able to generate protective CTL responses. We performed a high throughput screening of libraries of drugs approved by international agencies to identify compounds and molecular pathways capable of enhancing Ag cross-presentation in DCs. For it, we developed a high-performance screening method by adapting the colorimetric B3Z presentation assay using JAWSII DC cell line and Ovalbumin (OVA) as Ag. After assayed 1760 drugs, we found 1.1% of them increased OVA cross-presentation. We validated these hits and functional analogs by performing dose-response assays with both JAWSII and GMCSF BMDCs. Almost all of hits are lysosomotropic drugs that could promote biomacromolecules accumulation. As lipid bodies (LB)-formation has been associated to DCs cross-presentation ability, five hits were evaluated for LBs formation in JAWSII cells by fluorescence microscopy. We found that Tolonium Chloride, Amodiaquine Dihydrochloride and Perhexiline Maleate increased the amount of LBs per cell. None of these five drugs produced an important increase neither in the MHCI-surface expression nor in the soluble OVA-endocytosis by JAWSII cells. In conclusion, we established a sensitive, fast and robust screening platform for compounds-search capable of stimulating Ag cross-presentation in DCs. Although the mechanism of action of these drugs is still under investigation, our preliminary results indicate that it is likely related to lipid metabolism.