Role of the capsule in phagocytosis of Cryptococcus neoformans.
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.
Kozel
T R
TR
Department of Microbiology, School of Medicine, University of Nevada School of Medicine, Reno 89557.
Pfrommer
G S
GS
Guerlain
A S
AS
Highison
B A
BA
Highison
G J
GJ
D000818:Animals; D003176:Complement C3 / Q000276:immunology; D003454:Cryptococcus / Q000276:immunology*; D003455:Cryptococcus neoformans / Q000276:immunology* / Q000648:ultrastructure; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008024:Ligands; D009895:Opsonin Proteins / Q000276:immunology; D010587:Phagocytosis; D011134:Polysaccharides / Q000276:immunology
D003176:Complement C3; D007074:Immunoglobulin G; D008024:Ligands; D009895:Opsonin Proteins; D011134:Polysaccharides