Effects of over-expression of TLR2 in transgenic goats on pathogen clearance and role of up-regulation of lysozyme secretion and infiltration of inflammatory cells.
BACKGROUND
Toll-like receptor 2 (TLR2) is important to host recognition of invading gram-positive microbes. In goats, these microbes can cause serious mastitis, anthrax, tetanus, and other problems. Transgenic goats constitutively over-expressing TLR2 in many tissues serve as a suitable model for the study of the role of TLR2 over-expression in bacterial clearance.


RESULTS
Capra hircus TLR2 over-expression vector (p3S-LoxP-TLR2) was used to generate transgenic goats by egg microinjection. The integration efficiency was 8.57%. Real-time PCR and immunohistochemical results confirmed that the goats over-expressing the TLR2 gene (Tg) expressed more TLR2 than wild-type goats (WT). Monocyte-macrophages from the bloodstreams of transgenic goats were stimulated with synthetic bacterial lipoprotein (Pam3CSK4) and by the promotion of interleukin-6 (IL-6) and IL-10 expression in vitro. The oxidative damage was significantly reduced, and lysozyme (LZM) secretion was found to be up-regulated. Ear tissue samples from transgenic goats that had been stimulated with Pam3CSK4 via hypodermic injection showed that transgenic individuals can undergo the inflammation response very quickly.


CONCLUSIONS
Over-expression of TLR2 was found to decrease radical damage to host cells through low-level production of NO and MDA and to promote the clearance of invasive bacteria by up-regulating lysozyme secretion and filtration of inflammatory cells to the infected site.
National key Lab of Agro-Biotechnology, China Agricultural University, Beijing 100193, People's Republic of China.
Shoulong
S
Deng
Kun
K
Yu
Baolu
B
Zhang
Yuchang
Y
Yao
Yufeng
Y
Liu
Haijuan
H
He
Hongtao
H
Zhang
Maosheng
M
Cui
Juncai
J
Fu
Zhengxing
Z
Lian
Ning
N
Li
D000818:Animals; D030801:Animals, Genetically Modified; D005260:Female; D015511:Goat Diseases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006041:Goats; D006651:Histocytochemistry / Q000662:veterinary; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008315:Malondialdehyde / Q000378:metabolism; D009113:Muramidase / Q000276:immunology / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D012313:RNA / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D051195:Toll-Like Receptor 2 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D015854:Up-Regulation
D008070:Lipopolysaccharides; D051195:Toll-Like Receptor 2; D009569:Nitric Oxide; D008315:Malondialdehyde; D012313:RNA; D009113:Muramidase