Expression of Toll-like receptor mRNA and cytokines in pigs infected with porcine reproductive and respiratory syndrome virus.
Field observations have suggested that porcine reproductive and respiratory syndrome virus (PRRSV) predispose pigs to secondary infections. The interaction between PRRSV and the secondary invaders has not yet been well elucidated. In this study, we investigated the mRNA expression of Toll-like receptors (TLR) in lymphoid organs and cells, and cytokine secretions by alveolar macrophages (AMs) and peripheral blood mononuclear cells (PBMCs) in response to pathogen-associated molecular patterns (PAMPs) in PRRSV-challenged pigs. TLR mRNA expressions were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and cytokine concentrations were determined using commercially available ELISA kits. PRRSV infection led to significantly increased secretions of IL-1beta and IL-6 by AMs of PRRSV-infected pigs. Infection of pigs with PRRSV also resulted in an increased secretion of IL-1beta by AMs in response to lipoteichoic acid (LTA) stimulation, and IL-6 by PBMCs in response to lipopolysaccharide (LPS) and LTA stimulation. Infection of pigs with PRRSV tended to up-regulate the mRNA expression of TLR2, 3, 4, 7 and 8 in at least one of the lymphoid tissues and cells. Further research is required to demonstrate the association between the enhanced expressions of the specific TLRs and the increased susceptibility to secondary agents with more severe clinical outcomes in PRRSV-infected pigs.
Liu
Ching-Hsing
CH
Department of Veterinary Medicine, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan, ROC.
Chaung
Hso-Chi
HC
Chang
Hsiu-Luan
HL
Peng
Yu-Tang
YT
Chung
Wen-Bin
WB
D000818:Animals; D016207:Cytokines / Q000096:biosynthesis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D016676:Macrophages, Alveolar / Q000276:immunology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000235:genetics / Q000276:immunology* / Q000473:pathology / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine; D051193:Toll-Like Receptors / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology
D016207:Cytokines; D012333:RNA, Messenger; D051193:Toll-Like Receptors