A novel IL-17-dependent mechanism of cross protection: Respiratory infection with mycoplasma protects against a secondary listeria infection

作者：Sieve Amy N; Meeks Karen D; Bodhankar Sheetal; Lee Suheung; Kolls Jay K; Simecka Jerry W; Berg Rance E^*

来源：European Journal of Immunology, 2009, 39(2): 426-438.

DOI：10.1002/eji.200838726

• Bacterial infection
• Cytokine
• Cytokine receptor
• Neutrophil

Immune responses to pathogens occur within the context of current and previous infections. Cross protection refers to the phenomena where infection with a particular pathogen provides enhanced resistance to a subsequent unrelated pathogen in an antigen-independent manner. Proposed mechanisms of antigen-independent cross protection have involved the secretion of IFN-gamma, which activates macrophages, thus providing enhanced innate immunity against the secondary viral or bacterial pathogen. Here we provide evidence that a primary infection with the chronic respiratory pathogen, Mycoplasma pulmonis, provides a novel form of cross protection against a secondary infection with Listeria monocytogenes that is not mediated by IFN-gamma, but instead relies upon IL-17 and mobilization of neutrophils. Mice infected with M. pulmonis have enhanced clearance of L. monocytogenes from the spleen and liver, which is associated with increased numbers of Gr-1( )CD11b( ) cells and higher levels of IL-17. This enhanced clearance of L. monocytogenes was absent in mice depleted of Gr-1( ) cells or in mice deficient in the IL-17 receptor. Additionally, both the IL-17 receptor and neutrophils were essential for optimal clearance of M. pulmonis. Thus, a natural component of the immune response directed against M. pulmonis was able to enhance clearance of L. monocytogenes.

• 出版日期2009-2