Defective Replication of Porcine Transmissible Gastroenteritis Virus in a Continuous Cell Line

During a search for established cell lines to produce large quantities of porcine transmissible gastroenteritis virus (TGEV), we observed bright immunofluorescent staining 6–12h after infection of pig kidney derived LLC-PK1 line. Infectious virus yield was, however, 2 log10 lower than that from secondary adult pig thyroid (APT/2) cell cultures, although small plaques were visible by three days in cultures maintained under agarose, suggesting limited replication. Attempts to adapt TGEV to the LLC-PK1 cell line by 10 serial 20h passes were unsuccessful.