Adherence of platelets to Candida species in vivo

The in vivo interactions of platelets with Candida species yeast cells were investigated in a murine model. Mice were injected intravenously via the l ateral caudal vein, and blood drawn by periorbital puncture was collected i n phosphate-buffered saline-formaldehyde to avoid in vitro platelet activat ion. The study of the clearance of blastoconidia of Candida albicans and Ca ndida glabrata showed that these cells disappeared quickly from the bloodst ream. Microscopic observation of blood samples, stained by Calcofluor white or May Grunwald Giemsa, demonstrated the rapid attachment of platelets to fungal elements of all the Candida spp, tested, The attachment of murine pl atelets to C, albicans cells, observed by scanning electron microscopy, rev ealed morphological changes. The platelets lost their discoid shape, genera ted pseudopodia, and flattened against the yeast cells, The reversibility o f platelet binding to C, albicans by chelating agents suggests a cation-dep endent link. In contrast, the fixation of C, glabrata and Candida tropicali s was not modified by chelating agents. The mechanisms involved in the in v ivo adherence of platelets to Candida cells may therefore differ according to the species of Candida.