Evaluation of LMH cell line to study chicken Toll-like receptor functions

Abstract

The aim of this study was to analyse Toll-like receptor (TLR) function in Leghorn male hepatoma (LMH) cells infected with Gallid Herpesvirus-1 (GaHV-1). To date, the chicken innate immune system is poorly understood and nothing is known about GaHV-1 and its interaction with TLRs. GaHV-1 belongs to the Alphaherpesvirinae and causes the economically important fowl disease infectious laryngotracheitis. Symptoms vary from loss in egg production to severe respiratory lesions and acute death. In order to analyse the potential of LMH cells as a tool for studying TLR functions the presence of TLR 3, 7 and 21 first had to be demonstrated. Thus, five novel real-time PCR based assays detecting TLR 3, 7 and 21 and additionally the interleukins 6 and 8 were established. After proving the presence of these mRNAs in LMH cells, the influence of infection with GaHV-1 on the mRNA expression was examined. Infection with GaHV-1 reduced the mRNA expression of TLR 3 and 7. No conclusive results were obtained concerning TLR 21. Interestingly, IL-6 mRNA expression was only detectable in cells being infected more than 24 hours. In contrast, IL-8 mRNA was expressed in all samples and also increased 24 hours p.i. Further, LMH cells were treated with TLR agonists, but no conclusive results were obtained other than all cells treated with TLR 3 agonists died. In summary, this study provides the first experiments analysing the influence of GaHV-1 infection on TLR and cytokine mRNA expression in LMH cells.