Conversely, administration of recombinant IL-17 to WT mice at the time of bacterial infection resulted in a significant increase in mRNA expression of Cxcl1, Cxcl2 and Cxcl5. As well as, the lactating mice receiving the IL-17 treatment exhibited severe structural damage to alveolar and a dramatically increased inflammatory cell infiltration, particularly neutrophils. This evidence concerns the gene CXCL5 and bacterial infectious disease.