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Identification of genetic predispositions to susceptibility towards bovine tuberculosis (bTB) for the purpose of improving herd resistance to bTB through marker/genomic selection has been one of the thrust areas of research in animal production. Immune response genes, such as Toll Like Receptors (TLRs) which are involved in mycobacterial recognition and activation of innate and adaptive immune responses and Tumor Necrosis Factor alpha (TNFa) which is a vital pro-inflammatory cytokine with pleiotropic roles in immune response that enables mounting of a strong microbicidal action, are potential strong candidates for exploring genetic basis of resistance. Present investigation was aimed at exploring the association of three SNPs (rs43702940, rs68343175 and rs55617317) in TLR1 gene and one SNP (rs109967811) in TNFa gene with susceptibility to bTB infection in cattle. In a case-control population of bTB established using single intradermal tuberculin test, three of the investigated SNPs were found to be polymorphic while rs43702940 revealed monomorphism. SNP loci rs109967811 in TNFa gene was found to be significantly (P < 0.01) associated with susceptibility to bTB in the study population. These findings suggest that SNPs rs109967811 located in exonic region of TNFa can likely serve as a potential marker against bTB infection in cattle upon validation in independent, larger resource population. [ABSTRACT FROM AUTHOR]

Interferon Gamma Receptor (IFNGR) genes play an important role in the immune response against mycobacteria by regulating the proinflammatory cytokine Interferon Gamma (IFNG) alongwith subsequent mycobactericidal milieu and are potential strong candidates for investigating genetic basis of disease resistance. Present investigation was aimed at exploring the association of one SNP in IFNGR1 gene and two SNPs in IFNGR2 gene with susceptibility/resistance against bovine tuberculosis infection in cattle. All the three SNPs under investigation (rs109049057, rs109579937 and rs110689128) revealed polymorphism. SNP loci rs109049057 was found to be significantly (P < 0.01) associated with susceptibility to bovine tuberculosis in cattle in our case control population. The SNP was non-synonymous, suggesting its functional role in the immune response against bovine tuberculosis. [ABSTRACT FROM AUTHOR]

Toll-like Receptor 9 (TLR9) play an important role in recognition of components of intracellular pathogens like Mycobacterium bovis and subsequent activation of both innate and adaptive immune response and is potential strong candidates for investigating genetic basis of disease resistance. Present investigation was aimed at exploring the association of four SNPs in TLR9 gene with susceptibility/resistance against bovine tuberculosis infection in cattle. Three of SNPs under investigation (rs210982793, rs207807011, rs209190268) revealed polymorphism whereas monomorphism was observed in SNP rs55617140. SNP loci rs210982793 and rs207807011 were significantly (P < 0.01) associated with susceptibility to bovine tuberculosis in the case control population. Both these SNPs loci were non-synonymous, thus suggestive of their functional role in the immune response against bovine tuberculosis. [ABSTRACT FROM AUTHOR]

Host genetic variation in disease resistance is mainly attributable to variability in host immune responses to infection. Analysis of variation in host gene expression following M. bovis exposure and infection in cattle offers scope for a better understanding of the molecular regulation of the immune response. Present investigation was conducted to analyze expression profiles of chemokines CXCR3 and CCL1 using qRT-PCR in M. bovis infected cattle and healthy controls and to assess whether any inherent gene expression patterns are visible for these key innate immune response genes. Distinctive gene expression patterns were observed between M. bovis infected cattle and healthy controls. Expression of CXCR3 gene was significantly upregulated (5.22 fold, p=0.0225) in PBMCs of M. bovis infected cattle vis a vis healthy controls. CXCR3 and its ligands are associated with inflammatory diseases of importance to livestock as well as with protective immunity to infectious diseases and tumors. However for CCL1 gene, non significant differences in gene expression were observed between in macrophages of M bovis infected cattle and healthy controls. Distinctive mRNA expression pattern offer potential for developing biomarkers for diseases in livestock. [ABSTRACT FROM AUTHOR]

Aim: 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. Materials and 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]