MPO and infection: If IL-1β in fact has a detrimental effect during melioidosis, inhibition of its activity should lower morbidity and mortality of mice infected with B. pseudomallei. As shown in figure 4G, administration of the IL-1 receptor antagonist IL-1ra protected mice from infection with lethal doses of B. pseudomallei. Mice treated with IL-1ra had decreased recruitment of inflammatory cells to the alveolar spaces (figure 4B, right graph) lower level of MPO in BALF (figure S3), and less severe lung pathology (data not shown).