Robust Th1 and Th17 immunity supports pulmonary clearance but cannot prevent systemic dissemination of highly virulent Cryptococcus neoformans H99

Am J Pathol. 2009 Dec;175(6):2489-500. doi: 10.2353/ajpath.2009.090530. Epub 2009 Nov 5.

Abstract

The present study dissected the role of a Th2 bias in pathogenesis of Cryptococcus neoformans H99 infection by comparing inhalational H99 infections in wild-type BALB/c and IL-4/IL-13 double knockout mice. H99-infected wild-type mice showed all major hallmarks of Th2 but not Th1/Th17 immunity in the lungs and lung-associated lymph nodes. In contrast, the IL-4/13(-/-) mice developed robust hallmarks of Th1 and Th17 but not Th2 polarization. The IL-4/IL-13 deletion prevented pulmonary eosinophilia, goblet cell metaplasia in the airways and resulted in elevated serum IgE, and a switch from alternative to classical activation of macrophages. The development of a robust Th1/Th17 response and classical activation of macrophages resulted in significant containment of H99 in the lungs of IL-4/13(-/-) mice compared with unopposed growth of H99 in the lungs of wild-type mice. However, IL-4/13(-/-) mice showed only 1-week longer survival compared with wild-type mice. The comparison of brain and spleen cryptococcal loads at weeks 2, 3, and 4 postinfection revealed that the systemic dissemination in IL-4/13(-/-) mice occurred with an approximate 1-week delay but subsequently progressed with similar rate as in the wild-type mice. Furthermore, wild-type and IL-4/13(-/-) mice developed equivalently severe meningitis/encephalitis at the time of death. These data indicate that the Th2 immune bias is a crucial mechanism for pulmonary virulence of H99, whereas other mechanisms are largely responsible for its central nervous system tropism and systemic dissemination.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Chemotaxis, Leukocyte
  • Cryptococcosis / immunology*
  • Cryptococcosis / pathology
  • Cryptococcus neoformans / immunology
  • Cryptococcus neoformans / pathogenicity*
  • Disease Progression
  • Interleukin-13 / deficiency
  • Interleukin-13 / genetics
  • Interleukin-13 / immunology
  • Interleukin-17 / immunology*
  • Interleukin-4 / deficiency
  • Interleukin-4 / genetics
  • Interleukin-4 / immunology
  • Macrophage Activation / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Knockout
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocyte Subsets / immunology*
  • Th1 Cells / immunology*
  • Th2 Cells / immunology
  • Virulence

Substances

  • Interleukin-13
  • Interleukin-17
  • Interleukin-4