Application of human lymphoid cells for the evaluation of antivirals against human adenovirus type 19: Zalcitabine has superior activity compared to cidofovir

Human adenovirus type 19 (HAdV-19) is a major cause of the epidemic keratoconjunctivitis. Outbreaks of keratoconjunctivitis are problematic to human health, especially for infants, the elderly, and immunocompromised individuals. However, the development of anti-HAdV drugs has been hampered by inconvenient screening systems; therefore, development of a simple screening method is highly desirable. In this study, we identified that HAdV-19 can infect a human lymphoid cell line transformed with human T-cell leukemia virus (MT-2 cells). MT-2 cells supported HAdV-19 replication and showed apparent cytopathic effects within five days post-infection. Using a thiazolyl blue tetrazolium bromide (MTT)-based colorimetric assay on MT-2 cells, we were able to detect the anti-HAdV-19 activities of previously reported nucleoside/tide compounds, including (S)-1–(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (cidofovir), 2′,3′-dideoxycytidine (zalcitabine) and 3′-deoxy-3′-fluorothymidine (trifluridine). Compared with previous methods, this system represents a more simple and rapid method to screen anti-HAdV-19 agents.