Studies on cell adhesion and concanavalin A-induced agglutination of Candida albicans after mannan extraction.
Candida albicans cells were treated with alkali and acid to extract preferentially the cell wall alpha-mannan. Cells were recovered at three stages, as extraction proceeded from mild to more extensive: Alk-1, Alk-2 and Alk + Acid. Yeast adhesion to human epithelial cells was then examined with an in-vitro adherence assay. Yeasts from all three stages of extraction adhered in significantly lower numbers to buccal mucosal cells than did unextracted yeasts. Adhesion was as low for Alk-1 cells as for those submitted to more complete mannan extraction. When yeast cells from all three stages were treated with Concanavalin A (Con A), a lectin probe with strong affinity for yeast alpha-mannans, and then subjected to the adherence assay, there was no significant change in adhesion. When yeast agglutinability by Con A was examined in tests with treated and untreated yeast cells, abundant agglutination occurred only with the untreated cells. However, Alk-1 cells, though lacking in adhesive capacity towards mucosal cells, showed significant agglutination. The results suggest that candidal adhesion is mediated by an alkali-soluble, mannan-containing moiety(ies) which appears to be lost early in the extraction process. Blockage of this moiety by Con A inhibits the adhesion of unextracted cells. Extracted cells lack this moiety but still possess enough structural mannan for Con A recognition and agglutination.
Sandin
R L
RL
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824.
D000371:Agglutination; D000372:Agglutination Tests; D002176:Candida albicans / Q000502:physiology* / Q000648:ultrastructure; D002448:Cell Adhesion; D002473:Cell Wall / Q000032:analysis / Q000378:metabolism; D003208:Concanavalin A / Q000494:pharmacology*; D006801:Humans; D008351:Mannans / Q000032:analysis / Q000378:metabolism*; D009061:Mouth Mucosa / Q000166:cytology / Q000382:microbiology*
D008351:Mannans; D003208:Concanavalin A