Abstract
To develop adenoviral cell- or tissue-specific gene delivery, understanding of the infection mechanisms of adenoviruses is crucial. Several adenoviral attachment proteins such as CD46, CAR and sialic acid have been identified and studied. However, most receptor studies were performed on non-human cells. Combining our reporter gene-tagged adenovirus library with an in vitro human gene knockout model, we performed a systematic analysis of receptor usage comparing different adenoviruses side-by-side. The CRISPR/Cas9 system was used to knockout CD46 and CAR in the human lung epithelial carcinoma cell line A549. Knockout cells were infected with 22 luciferase-expressing adenoviruses derived from adenovirus species B, C, D and E. HAdV-B16, -B21 and -B50 from species B1 as well as HAdV-B34 and -B35 were found to be CD46-dependent. HAdV-C5 and HAdV-E4 from species E were found to be CAR-dependent. Regarding cell entry of HAdV-B3 and -B14 and all species D viruses, both CAR and CD46 play a role, and here, other receptors or attachment structures may also be important since transductions were reduced but not completely inhibited. The established human knockout cell model enables the identification of the most applicable adenovirus types for gene therapy and to further understand adenovirus infection biology.
Highlights
More than 100 types of human adenoviruses (HAdV) have been described and classified into species A–G [1]
For DSG2, we detected a positive signal for 98.6% of the analyzed cells, and for CD80 and CD86, no expression was detected on A549 cells (Supplementary Table S1)
Transduction experiments with the well-studied adenoviruses HAd-C5 and HAdV-B35 confirmed existing data indicating that these viruses use CAR and CD46, respectively, for cell entry [23,25,30]
Summary
More than 100 types of human adenoviruses (HAdV) have been described and classified into species A–G [1] These non-enveloped viruses are of strong scientific interest due to their use in gene therapy and as threatening pathogens in immunocompromised patients. CAR has been shown to bind fibers from exponents of adenovirus species A and C–E [33] It belongs to the immunoglobulin superfamily and forms homodimers in epithelial cell–cell adhesions. Once the infected cells produce viral particles, they bind to CAR and open tight junctions, permitting viral escape across epithelial borders [34]. These proteins are described as receptors for certain Ad types, a side-by-side comparison of receptor usage by the plethora of Ad types is lacking. Recent microbiological receptor studies were based on laborious blocking assays or transient knockdown through siRNA experiments, bearing limitations due to the considerable effort required
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
