<div><p>A <i>Pseudomonas aeruginosa</i>–<i>Caenorhabditis elegans</i> pathogenesis model was utilized to assess immunotoxic effects of arsenic trioxide (As<sub>2</sub>O<sub>3</sub>). After 2 h of As<sub>2</sub>O<sub>3</sub> exposure, 500 µmol L<sup>−1</sup> and 1 mmol L<sup>−1</sup> As<sub>2</sub>O<sub>3</sub> treatment significantly decreased median survivals of <i>C. elegans</i> (10 h after L4/adult molt). However, 2 h of As<sub>2</sub>O<sub>3</sub> exposure caused no significant changes in the survivals rates of <i>C. elegans</i> (2 h after L4/adult molt). Notably, a significant dose-related immunoenhancement was observed in <i>C. elegans</i> (2 h after L4/adult molt) after 12 h of arsenite exposure.</p></div
