Development of High-growth African Swine Fever Virus (ASFV) in MA-104 Cells

Abstract The goal of this study was to identify a candidate commercial cell line for the replication of African swine fever virus (ASFV) by comparing several available cell lines with various medium factors. In the sensitivity test of cells, MA104 and MARC-145 had strong potential for ASFV replication. Next, MA104 cells were used to compare the adaptation of ASFV obtained from tissue homogenates and blood samples in various infectious media. At the 10th passage, the ASFV obtained from the blood sample had a significantly higher viral load than that obtained from the tissue sample (P = 0.00), exhibiting a mean Ct value = 20.39 ± 1.99 compared with 25.36 ± 2.11. For blood samples, ASFV grew on infectious medium B more robustly than on infectious medium A (P = 0.006), corresponding to a Ct value = 19.58 ± 2.10 versus 21.20 ± 1.47. ASFV originating from blood specimens continued to multiply gradually and peaked in the 15th passage, exhibiting a Ct value = 14.36 ± 0.22 in infectious medium B and a Ct value = 15.42 ± 0.14 in infectious medium A. However, there was no difference (P = 0.062) in ASFV growth between infectious media A and B when ASFV was cultured from tissue homogenates. In this study, a model was developed to enhance ASFV replication through adaptation to MA104 cells and the lack of mutation in serial culture passages may serve to maintain the immunogenicity of ASFV isolates when they are developed as vaccine candidates .