HAdV-7 and HAdV-3: A Comparative Study on Tropism, Replication, and Receptor Mediated Infection in Human Cell Lines

Background: To explore the tropism and replication proficiency of specific human adenoviruses, namely HAdV-7 and HAdV-3, across a spectrum of human cell lines, and to elucidate the relationship between viral infection and the levels of hDSG2 and hCD46 receptor expression. Methods: We employed a variety of human cell lines originating from diverse tissues to evaluate viral replication. Viral titers were determined using a standard plaque assay, and cell infection was evaluated by immunofluorescence staining for viral hexon protein. Flow cytometry was used to assess the surface expression of hDSG2 and hCD46. The statistical analysis was conducted with GraphPad Prism version 6 software. Results: HAdV-7 demonstrated higher replication efficiency than HAdV-3 in most cell lines, with significant replication observed in Hep-2, Calu-3, HEK-293, and HeLa cells. The expression of hDSG2 and hCD46 correlated with viral susceptibility, indicating that these receptors are vital for viral adhesion and penetration. Notably, HAdV-7 showed a stronger association with hDSG2, which may explain its increased pathogenicity. Conclusions: Our study provides evidence that HAdV-7 has a broader tropism and higher replication efficiency in human cell lines compared to HAdV-3, with hDSG2 being a potential target for antiviral interventions. These results deepen our comprehension of HAdV-7 pathogenesis and could inform the creation of innovative treatment approaches for adenovirus infections.