Chromosomes Stability and Growth Assessment of a Newly Established Lamb Heart Cell Line Sensitive to Lumpy Skin Disease Virus

Abstract

Lumpy skin disease virus (LSDV) belongs to the Poxvirus family and is usually isolated, characterized and grown on embryonated eggs or primary cells. While embryonated chicken eggs and primary cells may not be available at all labs and could be risky at use due to potential endogenous or exogenous contamination, primary cell cultures usually show a limited number of passages. Nevertheless, both the Madin-Darby bovine kidney (MDBK) cell line and Vero cells were found to be susceptible to LSDV, but only MDBK showed cytopathic effect and the obtained virus titers were lower than those of primary fetal heart cells. In this study, a stable lamb heart cell line sensitive to LSDV has been developed from the primary fetal heart cells. Studies on the characterization and stability of this cell line and optimal growth conditions were conducted. The obtained results revealed a successful passaging until the 60 th subculture. Chromosome analysis of heart cells at passage 60 revealed that >90% of cells were diploid cells. GTG-banding karyotyping confirmed that the chromosome diploid number was 54 (2n=54, XY). Viability of cells was 80 % after recovery from cryo-preservation. Population doubling time (PDT) was about 75 h. GMEM, and McCoy's media supplemented with 10% FBS supported optimum growth conditions compared to the other types of tested media. The cells were highly susceptible to the LSDV, demonstrating the presence of severe cytopathic effects and an increase of two log10 titers in the virus harvest compared to MDBK cells. In conclusion, this study indicated that the developed heart cell line was stable and positively reflected on the quality and cost of vaccine production.