Characterization of Razi Bovine Kidney (RBK) Cell Line as a Sensitive Cell to Bovine Herpesvirus-1 (BoHV-1)

Viruses are obligate parasites that completely rely on host cells for survival and replication. Razi Bovine Kidney (RBK) cell line was introduced and developed by the Razi Vaccine and Serum Research Institute. It has been successfully established as a continuous cell line over successive passages. As demonstrated in this experimental study, the RBK cells have shown suitable sensitivity to certain viruses, including Bovine Herpesvirus-1 (BoHV-1) virus. In the present research, the RBK cell line characteristics were analyzed using molecular and karyotype methods and growth specifications. Cloning of the RBK cell line was performed using the limited dilution method, and each cell clone was quantitatively and qualitatively characterized. Four cell clones were compared based on their sensitivity to the BoHV-1 virus. Then, the RBK-D5 clone was selected as the most appropriate cell line for further studies. The RBK-D5 was subjected to tests for identity, chromosomal analysis, and doubling time. In the end, the origin of this cell line was confirmed by the PCR method. It was observed that the cell line exhibited karyotype diversity due to aneuploidy, which can be responsible for the procreation of chromosomal instability. This diversity represents chromosomal changes in the continuous cell line that carries the characteristic of an immortalized cell line. The RBK-D5 was found to be more sensitive to the BOHV-1 virus. Surprisingly, its titer was evaluated at 10^8.5 CCID50/ml. The obtained results suggested that the RBK cell line is suitable for the BoHV-1 virus and can be useful for virus detection, propagation, and quality control or viral titration.