9^th European Immunology Conference associated with Antibody Engineering Meeting

IFN-α activates the transcription of various IFN-stimulated genes (ISGs) in virus infected cells. Proteins encoded by ISGs block viral transport into the host cell and inhibit viral gene transcription and translation. Due to the existence of 13 diff erent high homologous isoforms of mouse IFN-α, an IFN-α  knockout mouse has not yet been established by conventional knockout strategies and CRISPR/Cas. We used an IFN-a knockdown strategy based on ER-intrabodies to inhibit IFN-a secretion in macrophages and dendritic cells, the main producers of IFN-α  aft er virus infection. To realize this strategy an ER intrabody was constructed from an anti-mouse IFN-α rat hybridoma recognizing 5 mouse IFN-α isoforms. We follow the hypothesis that an intrabody recognizing 5 high homologous isoforms of the proteins will be able to knockdown all isoforms. Th e secretion of IFN-α was signifi cantly inhibited by the intrabody in stable intrabody expressing RAW 264.7 macrophages and D1 dendritic cells as demonstrated by ELISA, Mx2-dependent luciferase assay and immunofl uorescence. Th is antibody has the potential to knockdown IFN-α in transgenic intrabody mice. Th ese animals must be very valuable in the future to study in detail the role of IFN-α during active- and chronic viral infections and in autoimmune diseases.