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Influence of Molecular Sizes of Cryptococcus neoformans Capsular Polysaccharide on Phagocytosis
Author(s) -
Yasuoka Akira,
Kohno Shigeru,
Yamada Hiroshi,
Kaku Mitsuo,
Koga Hironobu
Publication year - 1994
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1994.tb02137.x
Subject(s) - cryptococcus neoformans , biology , phagocytosis , microbiology and biotechnology , polysaccharide , cryptococcus , cryptococcosis , biochemistry
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 μm), 39.8% in YC‐5 (capsule size 0.8‐1.5 μm), 20.3% in YC‐27 (capsule size 0.6‐1.1 μm), 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.