Development of a real-time RT-PCR for detection of Toll-like receptor2 and Toll-like receptor4 mRNAs in bursals and thymus of chicken infected with virulent NDV

Toll like receptor 2(TLR2) and Toll like receptor 4(TLR4) are crucial in pathogen recognition by the immune system. In present study,a real-time reverse-transcription PCR(RRT-PCR) based on SYBR GreenIwas developed for quantitative analysis of chicken TLR2 and TLR4 mRNA. SPF chickens were infected virulent Newcastle disease virus(vNDV),and TLR2 and TLR4 mRNA levels in the bursals and thymus was detected at 36 and 48 h post infection(PI) . The results showed that the RRT-PCR assay was highly specific,and had a sensitivity for detection of 108 copies TLR2 and 461 copies TLR4 mRNAs,repectively. The expression levels of TLR2 and TLR4 mRNA were down-regulation in bursals and thymus 36 h PI. However,the expression level of TLR2 was up-regulated in both bursals and thymus 48 h PI. The TLR4 expression level in thymus was also up-regulated at 48 h PI,but down-regulated in bursals. Our results indicated that TLR2 and TLR4 may play an important role in responsing to NDV infection.