Role of the capsule in phagocytosis of Cryptococcus neoformans

Rev Infect Dis. Jul-Aug 1988;10 Suppl 2:S436-9. doi: 10.1093/cid/10.supplement_2.s436.

Abstract

The capsule is closely associated with the virulence of Cryptococcus neoformans. The capsule inhibits phagocytosis by macrophages, monocytes, and neutrophils. Studies in our laboratory have shown that incubation of encapsulated cryptococci in normal human serum leads to deposition of large amounts of C3 fragments at the surface of the yeast and lesser amounts of IgG within the capsule. Thus, the capsule mediates two biologic activities with opposing effects. It is our current view that phagocytosis of the yeast is dependent on a balance between the antiphagocytic action of cryptococcal polysaccharide and the ability of the yeast to focus opsonically active complement fragments and the IgG at the capsular surface.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Complement C3 / immunology
  • Cryptococcus / immunology*
  • Cryptococcus neoformans / immunology*
  • Cryptococcus neoformans / ultrastructure
  • Humans
  • Immunoglobulin G / immunology
  • Ligands
  • Opsonin Proteins / immunology
  • Phagocytosis*
  • Polysaccharides / immunology

Substances

  • Complement C3
  • Immunoglobulin G
  • Ligands
  • Opsonin Proteins
  • Polysaccharides