A. Standard experimental protocol. On days -14 and -7, BALB/c mice were inoculated intranasally with 109 cfu L. plantarum (LP), 109 cfu L. reuteri (LR), or PBS + 1% BSA vehicle control (PBS). On day 0, all mice were inoculated with pneumonia virus of mice (PVM; 2000 virion copies/μL). B. Survival of mice inoculated as indicated with LP, LR or PBS prior to virus infection, n = 10 mice per group, representative of at least two independent experiments; ***p < 0.001 C. Granulocytes detected in bronchoalveolar lavage (BAL) fluid at time points indicated (day -6, day -4, day -1 as per Fig. 1A; n = 5 – 7 mice per time point). Horizontal bars indicate mean values; statistical significance **p < 0.01; ***p < 0.001. D. Survival of mice primed with LP or PBS days -14 and -7 and challenged with PVM 13 weeks (91 days) later; n = 10 mice per group, **p < 0.01.