title: Influence of molecular sizes of Cryptococcus neoformans capsular polysaccharide on phagocytosis.
abstract: The role of capsular polysaccharides (CPS) of Cryptococcus neoformans in phagocytosis by murine alveolar macrophages was investigated in four strains of C. neoformans serotype A, YC-11, YC-5, YC-27 and YC-13. Phagocytosis rates increased markedly after adding 10% mouse serum, compared to fetal calf serum. The reverse relation between capsular thickness of C. neoformans and phagocytosis by alveolar macrophages was observed except in YC-27, which had thin capsules and high virulence. The phagocytosis rate in mice serum was 17.3% in YC-11 (capsule thickness 2.8-3.5 microns), 39.8% in YC-5 (capsule size 0.8-1.5 microns), 20.3% in YC-27 (capsule size 0.6-1.1 microns), and 62.8% in YC-13 (capsule not detected microscopically). The CPS of YC-11, YC-5, and YC-27 analyzed by gel-filtration using CL-2B showed high molecular fractions near the void volume. However, the CPS of YC-13 showed only low molecular fractions. The widely eluted CPS of YC-11 was separated into 3 fractions and each fraction was added in the phagocytosis assay of YC-13. Phagocytosis was markedly suppressed particularly by the addition of a higher molecular fraction. These results suggest that phagocytosis of C. neoformans by alveolar macrophages is influenced by the molecular sizes of the CPS.
authors.affiliation: Second Department of Internal Medicine, School of Medicine, Nagasaki University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yasuoka
authors.forename: S
authors.initials: S
authors.lastname: Kohno
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Kaku
authors.forename: H
authors.initials: H
authors.lastname: Koga
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D003455:Cryptococcus neoformans / Q000737:chemistry* / Q000472:pathogenicity; D016676:Macrophages, Alveolar / Q000276:immunology; D051379:Mice; D010587:Phagocytosis / Q000276:immunology*; D011134:Polysaccharides / Q000737:chemistry*; D014774:Virulence
chemical_list: D011134:Polysaccharides; C014426:cryptococcal polysaccharide; C027478:glucuronoxylomannan