Inhibition of phagocytosis by cryptococcal polysaccharide: dissociation of the attachment and ingestion phases of phagocytosis
- 1 July 1976
- journal article
- research article
- Published by American Society for Microbiology in Infection and Immunity
- Vol. 14 (1), 62-67
- https://doi.org/10.1128/iai.14.1.62-67.1976
Abstract
The effects of cryptococcal polysaccharide and selected serum factors on the attachment of Cryptococcus neoformans to [mouse peritoneal] macrophages and the subsequent ingestion of yeast cells by macrophages were investigated. Percent attachment was measured after incubation of yeast cells with macrophages at 4.degree. C. Percent engulfment was determined after incubation of yeast cells and macrophages at 37.degree. C. Nonencapsulated yeast cells readily attached to macrophages at the low temperature and were engulfed at a high rate at 37.degree. C; encapsulated yeast cells attached to macrophages at low rates and were engulfed at low rates. Addition of varying doses of purified cryptococcal polysaccharide to nonencapsulated yeast cells inhibited attachment at approximately the same concentration of polysaccharide required for inhibition of engulfment. Nonencapsulated yeast cells that attached to macrophages at 4.degree. C were eluted from the macrophages by addition of purified cryptococcal polysaccharide to the incubation medium. Heat-labile opsonins were not required for attachment of yeast cells to macrophages, but they were necessary for maximal initial rates of phagocytosis. Heat-stable components of serum facilitated attachment of cryptococci, but their most important function appeared to be triggering the ingestion of attached yeast. Specific [rabbit] antiserum had no effect on the attachment and engulfment of nonencapsulated cryptococci, and the antiserum produced only a small enhancement of the engulfment of encapsulated cryptococci.This publication has 21 references indexed in Scilit:
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