Hexon-based scaffold for generation of diagnostic monoclonal antibodies against diverse adenovirus types

Abstract

Infectious diseases hold one of the most crucial places in healthcare. In Russia, annual prevalence of infectious diseases comprises around 50 million cases, wherein acute respiratory viral infections cover up to 90%. In non-influenza (non-peak) season, adenoviruses, respiratory syncytial virus, parainfluenza viruses etc. represent the main infectious cause of acute respiratory viral infections. Adenovirus-induced infections are characterized by heterogeneous manifestations poising them both as an interesting challenge, yet difficult in clinical diagnostics. Use of rapid, sensitive and specific tests is of high priority for routine clinical laboratory practice. In Russia, differential diagnostics of adenoviral infections includes a widely used ELISA and immunofluorescence analysis based on polyclonal specific sera. Importantly, a pattern and range of specific reactions depend on origin of animal-derived antibodies and their composition. Introduction of monoclonal antibodies specific to certain viral antigenic epitopes ensures high sensitivity and specificity allowing to reach an expected standardization level for such diagnostic products. Adenovirus hexon protein bears genus-specific antigens and relatively conserved amino acid sequence among diverse adenoviruses. Moreover, it is produced at high amount in infected cells and may be purified in a native form. Moreover, it is produced at high amount in infected cells and may be purified in a native form, thereby posing it as a promising antigen for producing monoclonal antibodies able to detect various adenoviruses types. A panel of adenovirus hexon-specific monoclonal antibodies was generated, which were further examined for biological and diagnostics properties. Western blotting data allowed to conclude that all of monoclonal antibodies generated by us were able to bind to adenovirus hexon oligomers. Specific activity of the new monoclonal antibodies against various adenovirus types was examined by ELISA and indirect immunofluorescence assay. In particular, monoclonal antibodies 4B7 and 6B12 were shown display top specific activity measured by ELISA (antibody titers comprised as high as 106). Moreover, monoclonal antibody 6B12 exhibited peak hexon-specific activity assessed in indirect immunofluorescence assay (against various adenovirus types), which resulted in prominent granular nuclear fluorescence in cells infected with adenovirus types 3, 4, 6, and 19. Thus, the data obtained evidence that monoclonal antibodies developed 4B7 and 6B12 maybe potentially used for developing high-quality adenovirus-specific diagnostic assays.