ISOLATION OF A MUTANT MDBK CELL-LINE RESISTANT TO BOVINE VIRAL DIARRHEA VIRUS-INFECTION DUE TO A BLOCK IN VIRAL ENTRY

A cell line, termed CRIB, resistant to infection with bovine viral dia rrhea virus (BVDV) has been derived from the MDBK bovine kidney cell l ine. CRIB cells were obtained by selection and cloning of cells surviv ing infection with a highly cytolytic BVDV strain. CRIB cells contain no detectable infectious or defective BVDV as ascertained by cocultiva tion, animal inoculation, indirect immunofluorescence, Western immunob lot, Northern hybridization, and RNA PCR. Inoculation of CRIB cells wi th 24 cytopathic and noncytopathic BVDV strains does not result in exp ression of Viral genes or amplification of input virus. Karyotype and isoenzyme analyses demonstrated that CRIB are genuine bovine cells. CR IB cells are as susceptible as the parental MDBK cells to 10 other bov ine viruses, indicating that these cells do not have a broad defect bl ocking viral replication. Transfection of CRIB cells with BVDV RNA or virus inoculation in the presence of polyethylene-glycol results in pr oductive infection, indicating that the defect of CRIB cells is at the level of virus entry. CRIB cells are the first bovine cells reported to be resistant to BVDV infection in vitro and may be a useful tool fo r studying the early interactions of pestiviruses with host cells. (C) 1995 Academic Press, Inc.