Analysis of Synchronous and Asynchronous In Vitro Infections with Homologous Murine Norovirus Strains Reveals Time-Dependent Viral Interference Effects
Louisa F. Ludwig-Begall,
Elisabetta Di Felice,
Barbara Toffoli,
Chiara Ceci,
Barbara Di Martino,
Fulvio Marsilio,
Axel Mauroy,
Etienne Thiry
Affiliations
Louisa F. Ludwig-Begall
FARAH Research Centre, Faculty of Veterinary Medicine, Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, Liège University, 4000 Liège, Belgium
Elisabetta Di Felice
Department of Diagnosis and Surveillance of Exotic Disease, IZS Istituto Zooprofilattico Sperimentale A&M G. Caporale, 64100 Teramo, Italy
Barbara Toffoli
FARAH Research Centre, Faculty of Veterinary Medicine, Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, Liège University, 4000 Liège, Belgium
Chiara Ceci
Faculty of Veterinary Medicine, Università degli Studi di Teramo, 64100 Teramo, Italy
Barbara Di Martino
Faculty of Veterinary Medicine, Università degli Studi di Teramo, 64100 Teramo, Italy
Fulvio Marsilio
Faculty of Veterinary Medicine, Università degli Studi di Teramo, 64100 Teramo, Italy
Axel Mauroy
FARAH Research Centre, Faculty of Veterinary Medicine, Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, Liège University, 4000 Liège, Belgium
Etienne Thiry
FARAH Research Centre, Faculty of Veterinary Medicine, Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, Liège University, 4000 Liège, Belgium
Viral recombination is a key mechanism in the evolution and diversity of noroviruses. In vivo, synchronous single-cell coinfection by multiple viruses, the ultimate prerequisite to viral recombination, is likely to be a rare event and delayed secondary infections are a more probable occurrence. Here, we determine the effect of a temporal separation of in vitro infections with the two homologous murine norovirus strains MNV-1 WU20 and CW1 on the composition of nascent viral populations. WU20 and CW1 were either synchronously inoculated onto murine macrophage cell monolayers (coinfection) or asynchronously applied (superinfection with varying titres of CW1 at half-hour to 24-h delays). Then, 24 h after initial co-or superinfection, quantification of genomic copy numbers and discriminative screening of plaque picked infectious progeny viruses demonstrated a time-dependent predominance of primary infecting WU20 in the majority of viral progenies. Our results indicate that a time interval from one to two hours onwards between two consecutive norovirus infections allows for the establishment of a barrier that reduces or prevents superinfection.
