Abstract Bovine leukemia virus (BLV) is a single-stranded RNA retrovirus whose persistence in infected cattle indicates that innate immune responses, particularly antiviral cytokines, are insufficient to control infection. Tumor necrosis factor alpha (TNF-α) is a key proinflammatory cytokine that may contribute to antiviral defense, acting through two membrane-bound receptors: TNF-α receptor I (TNF-α RI) and TNF-α receptor II (TNF-α RII). Both receptors participate in apoptotic and immune-regulatory pathways. This study aimed to investigate the – 824 A/G polymorphism in the promoter region of the TNF-α gene and to quantify TNF-α RI and TNF-α RII transcript levels, assessing their association with proviral load and persistent lymphocytosis (PL) in Holstein cattle. Blood samples from 140 cows were analyzed for TNF-α genotypes and receptor mRNA expression. Data were normalized and analyzed using one-way analysis of variance (ANOVA) to assess differences in gene expression among the experimental groups. The TNF-α G/G genotype was significantly associated with increased odds of BLV infection ( p =0.006). TNF-αRI mRNA expression differed significantly between BLV-positive and BLV-negative cows ( p =0.0017), whereas TNF- αRII expression showed no differences according to infection status ( p =0.999). In BLV-negative animals, TNF-αRI and TNF-αRII expression levels differed significantly, with lower RII expression ( p 0.05). The results indicate an association between TNF-α genetic variation, receptor expression patterns, and BLV infection status, suggesting that TNF-α signaling may contribute to the host– virus interaction during BLV infection. Further longitudinal and functional studies are required to clarify the biological mechanisms linking TNF-α regulatory polymorphisms with viral persistence and disease progression.
Úsuga-Monroy et al. (Sun,) studied this question.