The Molecular Target Screening Of SNARE In Cross-presentation Of Dendritic Cells

Objective and Background: Cross-presentation is an antigen processing pathway that exogenous antigen presented into the MHC-â… molecule restricted process program. More and More evidences demonstrate that cross presentation is an important route for priming CD8+ T cells response and effectively clearing tumor, virus-infected cells and intracellular microorganism. Dendritic cells are major antigen cross presentation cells in vivo. Cross-presentation of dendritic cells is a complex process which includes antigens uptake, phagosome formation and finally MHC I-peptide complexes translocation onto plasma membrane. In eukaryotes, membrane trafficking and fusion is under control of SNAREs. Further investigations on the relationship of cross presentation and SNAREs may provide opportunities to develop new immunotherapy strategies for autoimmune disease and vaccine.Methods: This study using siRNA to screen an RNAi library against 33 mouse SNAREs. First, we used ovalbumin as a model antigen and established an efficient endogenous ntigen presentation assay system with a T cell hybridoma. Then, we constructed a siRNA lentivirus library against the 33 members of mouse SNARE protein family. Base on these works, we screened exogenous antigen cross-presentation of dedritic cell with the library.Results: Using ovalbumin expressing bacteria as a particle antigen, we screened an RNAi library against 33 mouse SNAREs, and identified 23 SNARE proteins that associated with cross-presentation in dendritic cells. These molecules mainly belong to two different SNARE subfamilies, Syntaxins and VAMPs. In these positive molecules, Syntaxin3, Syntaxin17 and Syntaxin18 play important roles in cross-presentation.Conclusion: As functional proteins deal with the vesicles identify, anchoring, fusion, SNARE molecules actually play a role in the exogenous antigen cross-presenting of dendritic cells. This result has provided theoretical support to virus prevention and cancer treatment, and provide opportunities to develop new immunotherapy strategies for autoimmune disease and vaccine.