PT also inhibits early neutrophil influx to the airways after infection by suppressing the early production of the neutrophil-attracting chemokines KC, LIX and MIP-2 by airway macrophages and epithelial cells [7].However, this latter property may not contribute significantly to bacterial growth, at least in naïve mice, since neutrophil depletion did not increase bacterial loads, possibly because of the inhibitory activities of PT and ACT on neutrophils [8]. This evidence concerns the gene CALCA and infection.