Influence of TLR2 polymorphism on innate immune system gene expression in Holstein cows

Toll-like receptor 2 (TLR2) is a critical component of the innate immune system. TLR2, a membrane-bound receptor, is expressed on the surface of specific immune cells, where it is involved in recognizing microbial components and initiating signaling cascades that activate immune cells, thereby playing a pivotal role in early pathogen detection and activating immune responses. This study investigated the effect of Toll-like receptor 2 gene polymorphism on the expression of genes associated with innate immune cell activation. The PCR-RFLP method was used to study single nucleotide polymorphism in exon 2 of the TLR2 gene 385 T/G (NC_037344.1 rs55617172) in 103 Holstein cows. The frequency of the TLR2T allele was 0.74, and that of the TLR2TT genotype was 53.4%. The effect of the TLR2 gene polymorphism on the expression of the genes of proinflammatory cytokines tumor necrosis factor (TNF), interleukin 6 (IL6), and interleukin 12B (IL12B) in peripheral blood mononuclear cells (PBMCs) from 29 cows was shown when PBMCs were stimulated with the TLR2 agonist lipoteichoic acid (LTA) or the Toll-like receptor 4 (TLR4) agonist lipopolysaccharide (LPS). PBMCs obtained from animals carrying the G allele of the TLR2 gene showed significantly increased expression of the proinflammatory cytokine genes TNF, IL6, and IL12B following stimulation with TLR2 or TLR4 agonists. The TLR2 genotype did not significantly affect the expression of genes encoding the Toll-like receptors TLR2 and TLR4 or the adaptor molecules MYD88 and TICAM2.