This increase in HRP flux was promoted by both PLY and 12-LOX, because (i) Δply Sp infection of WT B6 monolayers resulted in twofold lower flux (P < 0.05) and (ii) WT Sp infection of Alox15−/− ALI monolayers resulted in fourfold lower flux (P < 0.0001; Fig. 2c, “mouse ALI”). This evidence concerns the gene ALOX12 and infection.