IN CATTLE HETEROZYGOSITY AT THE A625C POLYMORPHIC SITE OF THE MyD88 GENE IS ASSOCIATED WITH RESISTANCE TO Mycobacterium bovis

The study demonstrates that in cattle the animals heterozygous at the MyD88 A625C polymorphic marker benefit of a five-fold reduced risk for active pulmonary tuberculosis (OR: 0.19; P: 6 x 10-12). The reduced risk however does not extend to the animals with latent pulmonary tuberculosis (OR: 0.83; P: 0.40). Heterozygosity at the A625C SNP is associated with intermediate levels of TNF- ?,IFN-?, and NO compared to the levels observed in the AA or CC homozygous genotypes. Deficiency as well as over-expression of pro-inflammatory cytokines favor tuberculosis. Thus, heterozygosity provides the animals with the optimal level of inflammation.