CR3 (CD11b/CD18) and CR4 (CD11c/CD18) are involved in complement-independent antibody-mediated phagocytosis of Cryptococcus neoformans.
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.
Division of Infectious Diseases, The Department of Medicine and The Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Carlos P
CP
Taborda
Arturo
A
Casadevall
D000818:Animals; D018821:CD18 Antigens / Q000235:genetics / Q000276:immunology*; D016466:CHO Cells; D002460:Cell Line; D003167:Complement Activation; D006224:Cricetinae; D003455:Cryptococcus neoformans / Q000276:immunology*; D007070:Immunoglobulin A / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D016167:Integrin alphaXbeta2 / Q000276:immunology*; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology; D016177:Macrophage-1 Antigen / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D009005:Monosaccharides / Q000494:pharmacology; D010587:Phagocytosis; D011134:Polysaccharides / Q000276:immunology / Q000494:pharmacology
D018821:CD18 Antigens; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D016167:Integrin alphaXbeta2; D037102:Lectins; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D009005:Monosaccharides; D011134:Polysaccharides; C027478:glucuronoxylomannan