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

Amy N. Sieve, Karen D. Meeks, Sheetal Bodhankar, Suheung Lee, Jay K. Kolls, Jerry W. Simecka, Rance E. Berg

Research output: Contribution to journalArticle

34 Scopus citations


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-γ, 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-γ, 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. Tbus, a natural component of the immune response directed against M. pulmonis was able to enhance clearance of L. monocytogene.

Original languageEnglish (US)
Pages (from-to)426-438
Number of pages13
JournalEuropean Journal of Immunology
Issue number2
StatePublished - Jun 25 2009



  • Bacterial infection
  • Cytokine
  • Cytokine receptor
  • Neutrophil

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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