Mycobacterium tuberculosis complex (MTC) causes bovine tuberculosis (bTB), a chronic infectious disease of Bovidea family characterised by the formation of granulomas in various organs. The host cytokine machinery plays an important role in providing protection against bTB infection. Therefore, the objective of the present study was to assess whether polymorphisms in candidate genes encoding important cytokine receptors are associated with bTB infection status of dairy cattle. Seven reported polymorphisms in interleukin (IL) genes were genotyped by using PCR-RFLP in a resource population of 84 dairy cattle with known bTB infection status and genotype analysis were performed individually for each gene via PROC LOGISTIC in the statistical software SAS. The three single nucleotide polymorphisms (SNPs) in IL12RB1 (rs210615796) and IL12RB2 (rs208115312 and rs135336138) were found to be monomorphic while for rest of the SNPs polymorphism in IL12RB1 (rs132856935 and rs110233569), IL12RB2 (rs211644228) and IL23R (rs42497589) genes was observed. This suggest the presence of these SNPs in the resource population. The population was in Hardy-Weinberg equilibrium (HWE) for all the SNPs studied. A moderate heterozygosity, polymorphism information content (PIC) value and allelic diversity were estimated at rs110233569 while corresponding low values for other SNPs observed. However, these SNPs were found to be non-associated with the bTB infection status of the resource population. These results need further validation in independent, large resource population and biological characterization is warranted with more effective case-control identification. In addition, other SNPs in these concerned genes could be further exploited for association studies.
Bovine tuberculosis, SNPs, Interleukin genes, PCR-RFLP, heterozygosity, PIC value and allelic diversity
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