Highly Sensitive Fetal Goat Tongue Cell Line for Detection and Isolation of Foot-and-Mouth Disease Virus

Abstract

A fetal goat cell line (ZZ-R 127) supplied by the Collection of Cell Lines in Veterinary Medicine of the Friedrich Loeffler Institute was examined for susceptibility to infection by foot-and-mouth disease (FMD) virus (FMDV) and by two other viruses causing clinically indistinguishable vesicular conditions, namely, the viruses of swine vesicular disease and vesicular stomatitis. Primary bovine thyroid (BTY) cells are generally the most sensitive cell culture system for FMDV detection but are problematic to produce, particularly for laboratories that infrequently perform FMD diagnostic tests and for those in countries where FMD is endemic that face problems in sourcing thyroid glands from FMD-negative calves. Strains representing all seven serotypes of FMDV could be isolated in ZZ-R 127 cells with a sensitivity that was considerably higher than that of established cell lines and within 0.5 log of that for BTY cells. The ZZ-R 127 cell line was found to be a sensitive, rapid, and convenient tool for the isolation of FMDV and a useful alternative to BTY cells for FMD diagnosis.

Availability of a fetal goat tongue cell line ZZ-R 127 for isolation of Foot-and-mouth disease virus (FMDV) from clinical samples collected from animals experimentally infected with FMDV

“…A previous study 2 confirmed the availability of ZZ-R 127 cells for FMDV isolation using cell culture supernatants and epithelial suspensions. In the current study, the availability was precisely confirmed using samples not evaluated previously.…”

“…However, the ZZ-R 127 cells are not susceptible to swine vesicular disease virus, which can cause similar clinical signs to FMD. 2 In addition, porcinophilic FMDV strains do not grow well in the ZZ-R 127 cells.…”

“…Afterward, the monolayers were washed and added to fresh medium; the cultures were incubated for 72 hr at 37°C in 5% CO 2 . A commercial medium a supplemented with 2.4 g/l of tryptose phosphate broth, 1% of 7.5% NaHCO 3 , 1% of 2.92% l-glutamine, and 2% of FCS, and a different commercial medium c supplemented with 10% of FCS were used as the fresh media for the IB-RS-2 cells and the ZZ-R 127 cells, respectively.…”

“…At the National Institute of Animal Health, Japan (NIAH), primary bovine kidney cells and IB-RS-2 cells are routinely used for diagnostic tests for FMD. 6,12 A previous study 2 reported that the fetal goat tongue cell line ZZ-R 127 was highly sensitive for the isolation of FMDV. The study evaluated its availability for FMDV isolation using cell culture supernatants and epithelial suspensions of various FMDV strains.…”

“…The World Organization for Animal Health (OIE) recommends that primary bovine thyroid (BTY) cells should be used for diagnostic tests on FMD because they are the most sensitive for the isolation of FMDV from clinical samples as described in the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 2012 (http://www.oie.int/fileadmin/Home/ eng/Health_standards/tahm/2.01.05_FMD.pdf ). However, because BTY cells cannot be passaged and easily frozen without impairing their sensitivity, 2,8 ensuring that there is always a fresh and suitable batch of the BTY cells available for diagnostic tests is quite laborious and expensive. 5 Therefore, most diagnostic laboratories routinely use other cells that are less susceptible to FMDV infection but more convenient to handle, such as other primary cells of bovine, ovine, and porcine origins 1,7 and permanent cell lines such as baby hamster kidney (BHK-21), 4,10 porcine kidney (IB-RS-2 3 and SK-6 9 ), and porcine kidney epithelial (PK-15) cells.…”