Carbohydrate moieties of microsporidian polar tube proteins are targeted by immunoglobulin G in immunocompetent individuals.
Microsporidia of the Encephalitozoon species are frequently found as opportunistic pathogens of immunocompromised patients, but very little is known about the prevalence and significance of Encephalitozoon infection in immunocompetent individuals. It was reported previously that 8% of Dutch blood donors and 5% of pregnant French women had an immunoglobulin G (IgG) immune response against specific organelles of Encephalitozoon intestinalis. These organelles, the so-called polar tube and anchoring disk, are used to penetrate membranes of host cells during infection. The unexpectedly high percentage of immunocompetent individuals with IgG against these organelles suggested that infection of humans with microsporidia might be more common than previously recognized. In the present study, we analyzed this anti-Encephalitozoon IgG response by using indirect immunofluorescence, Western blotting, two-dimensional gel electrophoresis, and chemical deglycosylation. Our results show that the antibody response is directed against the posttranslational carbohydrate modification of the major polar tube protein (polar tube protein 1) and carbohydrate moieties of proteins in the anchoring region of the polar tube of Encephalitozoon. In addition, the antibodies were found to decrease the infectivity of E. intestinalis in vitro. The significance and possible origin of these prevalent antibodies are discussed.
Peek
Ron
R
Section Parasitology, Department of Medical Microbiology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. r.peek@amc.uva.nl
Delbac
Frédéric
F
Speijer
Dave
D
Polonais
Valérie
V
Greve
Sophie
S
Wentink-Bonnema
Ellen
E
Ringrose
Jeffrey
J
van Gool
Tom
T
D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D000917:Antibody Formation; D000953:Antigens, Protozoan / Q000276:immunology; D002241:Carbohydrates / Q000276:immunology; D002478:Cells, Cultured; D016819:Encephalitozoon / Q000276:immunology*; D016890:Encephalitozoonosis / Q000276:immunology*; D006031:Glycosylation; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007121:Immunocompetence; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D015388:Organelles / Q000276:immunology; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D002241:Carbohydrates; D007106:Immune Sera; D007074:Immunoglobulin G; D015800:Protozoan Proteins