Assessment of the sensitivity of primary cells and cell lines to the Southern African Territories (SAT) serotypes in the diagnosis of foot-and-mouth disease virus

Virus isolation is the gold standard for foot-and-mouth disease virus (FMDV) detection in diagnostic procedures. This technique is heavily reliant on the use of sensitive cells for rapid and accurate detection of FMDV. To investigate the sensitivity of RM (primary lamb kidney cells), BHK-21 (baby hamster kidney cells) and IR-P1 (a derivative of female pig kidney cells) to infection with FMDV of the Southern African Territories (SAT) serotypes, we examined the virus concentration required to induce cytopathic effect (CPE) on each cell type. The results suggested that sensitivity of RM and IR-P1 cells was high and not significantly different (P < 0.05). BHK-21 however, exhibited low sensitivity to the strains used. Comparisons of three batches of each cell type were also done to establish the consistency of the sensitivity of these cells to FMDV infection. IR-P1 and BHK-21 cell batches gave consistent results for all samples used whereas RM cells showed significant differences (P > 0.05) between batches. TCID 50/ml was used to determine the viral titre required to induce CPE. IR-P1 cell line proved to have consistently higher TCID50/mL for all cell batches while RM cell batches displayed a difference in TCID50/mL values. The IR-P1 cell line was concluded to be a good cell culture system for virus isolation as it showed relatively high and reproducible sensitivity to all the FMDV strains used. The findings of this study indicate that the use of IR-P1 cell line could be considered for FMDV diagnostic work.