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Updated: Sep 30, 2026

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans
Published on: December 19, 2014
CR3 (CD11b/CD18) and CR4 (CD11c/CD18) are involved in complement-independent antibody-mediated phagocytosis of
Carlos P Taborda1, Arturo Casadevall
1Division of Infectious Diseases, The Department of Medicine and The Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Abstract:
IgM and IgA to the Cryptococcus neoformans capsular glucuronoxylomannan (GXM) promote complement-independent phagocytosis by macrophages with efficiency comparable to that of IgG1. IgM- and IgA-mediated phagocytosis of C. neoformans was proportional to CR3 expression, inhibited by Abs to CR3 (CD11b/CD18) and CR4 (CD11c/CD18), and dramatically reduced with macrophages of CD18-deficient mice. IgM and IgA promoted ingestion of yeast cells by CHO cells expressing CR3 and CR4. In contrast, IgG1-mediated phagocytosis was only partially inhibited by Abs to CR3 and CR4. Phagocytosis by IgM and IgA but not IgG1 was inhibited by soluble GXM, which binds CD18. Involvement of CR in antibody-mediated complement-independent phagocytosis indicates a new link between innate and adaptive immune systems.
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