Toll-like receptor 3 (TLR3), together with pro-inflammatory cytokines, appears to play a significant role in genetic resistance to Marek's disease (MD) in chickens, according to new research by Santosh Haunshi of the Directorate of Poultry Research in India and Hans H. Chen of the USDA's Agricultural Research Service

In the introduction to their paper in the current issue of Poultry Science, they explain that the TLR signalling pathway is one of the innate immune defence mechanisms against pathogens in vertebrates and invertebrates. However, the role of TLR in non-MHC genetic resistance or susceptibility to MD in the chicken is yet to be elucidated.

Haunshi and Chen infected chicken embryo fibroblast cells from MD-susceptible and MD-resistant lines either with Marek’s disease virus (MDV) or treated with polyionosinic-polycytidylic acid, a synthetic analogue of dsRNA.

They then studied the expression of the TLRs and pro-inflammatory cytokines eight and 36 hours later by quantitative reverse transcriptase PCR.

Their findings reveal that MDV infection and polyionosinic-polycytidylic acid treatment significantly elevated the mRNA expression of TLR3, IL6 and IL8 in both susceptible and resistant lines.

Furthermore, basal expression levels in uninfected CEF for TLR3, TLR7 and IL8 genes were significantly higher in resistant chickens than susceptible chickens.

Reference

Haunshi S. and H.H. Cheng. 2014. Differential expression of Toll-like receptor pathway genes in chicken embryo fibroblasts from chickens resistant and susceptible to Marek’s disease. Poultry Science. 93(3):550-555. doi: 10.3382/ps.2013-03597

Further Reading

You can view the full report by clicking here.
Find out more about Marek's Disease by clicking here.