Purinergic and Energy Metabolism Disruption in Oxidative Stress-Mediated Immunotoxicity Induced by Aflatoxin B₁ and...

Aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁) are cereal-contaminating mycotoxins; co-exposure to these compounds is associated with hepatocellular carcinoma, although the underlying immunological mechanisms remain unclear. This study aimed to investigate the impact of AFB₁ and FB₁, individually and combined, on immune cell function, focusing on Th1-associated cytokines, cytotoxic capacity, oxidative stress involvement, and energy and purinergic metabolism. Rat splenocytes and intrahepatic leukocytes were exposed to AFB₁ (20 μM), FB₁ (10 μM), or a mixture of both (MIX), in the presence or absence of catalase. Cytokines and phenotypes were assessed by flow cytometry and ELISA, cytotoxicity by co-culture assays, and intra/extracellular adenine nucleotides and purines by HPLC. The MIX significantly impaired Th1-like differentiation and reduced IFNγ and TNFα production, FAS-L expression and cytolytic activity while increasing IL4 production, indicating a shift toward a Th2-like profile. These effects were prevented by catalase, supporting a key role for oxidative stress. Co-exposure disrupted intracellular energy balance, decreasing adenosine triphosphate (ATP) levels, ATP/ADP ratios, and total adenine nucleotide pools. It also enhanced purine degradation, extracellular ATP release and adenosine accumulation, suggesting altered purinergic signaling. Consequently, AFB₁-FB₁ co-exposure disrupts immune function through interconnected redox and metabolic mechanisms, promoting an immunosuppressive environment that may favor tumor progression.