Single nucleotide polymorphisms in toll-like receptor genes and case-control association studies with bovine tuberculosis.
OBJECTIVE
Toll-like receptor 2 (TLR2) and TLR4 genes play critical roles in host recognition of Mycobacterium bovis infection and initiation of innate and adaptive immune response. The present study was aimed at exploring the association of seven single nucleotide polymorphisms (SNPs) in TLR2 and TLR4 genes with susceptibility/resistance against bovine tuberculosis (bTB) infection in cattle.


METHODS
A case-control resource population of 35 positive and 45 negative animals was developed after screening with single intradermal tuberculin test for bTB. Resource population was screened for SNPs in TLR2 and TLR4 genes using polymerase chain reaction-restriction fragment length polymorphism. The PROC LOGISTIC procedure of SAS 9.3 was used to find an association of allelic and genotypic frequencies with bTB.


RESULTS
In TLR2 gene, two of SNPs under study (rs55617172 and rs68268253) revealed polymorphism while in the case of TLR4 gene all four SNPs under investigation (rs8193041, rs207836014, rs8193060, and rs8193069) were found to be polymorphic in case-control population. SNP locus rs55617172 in TLR2 gene was found significantly (p<0.01) associated with susceptibility/resistance to TB in cattle.


CONCLUSIONS
These findings indicate the presence of SNPs in TLR2 and TLR4 genes in our resource population. Upon validation in independent, large resource population and following biological characterization, SNP rs55617172 can be incorporated in marker panel for selection of animals with greater resistance to bTB.
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Ashish
A
Bhaladhare
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Deepak
D
Sharma
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Amit
A
Kumar
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Arvind
A
Sonwane
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Anuj
A
Chauhan
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Ranvir
R
Singh
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Pushpendra
P
Kumar
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Ramji
R
Yadav
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Mohd
M
Baqir
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Bharat
B
Bhushan
Division of Animal Genetics, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Om
O
Prakash
bovine tuberculosis; immune response; resistance; single nucleotide polymorphisms; toll-like receptors