Propagation of infectious bovine rhinotracheitis (bovine herpes-1) virus in murine primary cell cultures.

Virus synthesis in BALB/C mouse lung and kidney primary cultures infected with infectious bovine rhinotracheitis (IBR) virus started between 6 and 8 hours after virus inoculation and reached a maximum titer of 5.5 log10 plaque forming units (PFU) at 48 hours postinfection (PI). Cytopathic effect (CPE) in cell cultures occurred at 8-10 hours and over 90% of the cells had CPE by 48 to 72 hours PI. The bulk of the newly replicated virus (60-80%) was cell-associated as determined by plaque assay of extracellular and intracellular virus. Pulse-chase experiments demonstrated incorporation of radioactive precursors into viral DNA and protein macromolecules. Viral DNA synthesis was initiated between 2 and 4 hours PI and was maximum at 4 to 6 hours. Viral proteins were detected at 4 hours and peaked between 6 and 8 hours PI. Enzyme-linked immunosorbant assay (ELISA) confirmed synthesis of specific viral proteins, which gradually increased during the virus growth cycle. Abstract in French is given at the end of the article.