Importance of α- and β/α-linked mannooligosaccharides in antibody response against C. dubliniensis.
A conjugate of C. dubliniensis cell-wall mannan and human serum albumin (HSA) induced significant level of anti-mannan IgGs in sera of immunized rabbits, whereas mannan alone was not immunogenic. Binding affinities of anti-mannan IgGs induced by the conjugate were evaluated by inhibition ELISA (iELISA) using mannooligosaccharides (dimer-octamer), derived from the side chains of C. dubliniensis mannan, as the inhibitors. Inhibition power of the mannooligosaccharides increased exponentially with their size, with dimer being the weakest (IC(50) = 4 mmol/L) and heptamer/octamer the strongest inhibitors (IC(50) = 0.01 mmol/L). In addition, the mannooligosaccharides proved effective as inhibitors against antiserum obtained from rabbits immunized with C. dubliniensis heat-killed cells, demonstrating a high correlation in the IC(50) values with anti-conjugate serum (Pearson's correlation coefficient r = 0.98; P < 0.01). These findings suggest that a) the mannooligosaccharides comprising the side chains of C. dubliniensis mannan may represent relevant points of interaction with host immune system during infection and b) anti-mannan antibodies induced by the two antigens (the mannan conjugate and the yeast) are of similar specificities.
Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38, Bratislava, Slovak Republic. chemlizi@savba.sk
Izabela
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Medovarská
Slavomír
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Bystrický
Zuzana
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Kossaczká
Eva
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Machová
D000818:Animals; D002175:Candida / Q000276:immunology*; D002473:Cell Wall / Q000737:chemistry / Q000276:immunology; D005260:Female; D005657:Fungal Vaccines / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007106:Immune Sera; D007074:Immunoglobulin G / Q000097:blood; D008351:Mannans / Q000737:chemistry / Q000276:immunology*; D009844:Oligosaccharides / Q000737:chemistry / Q000276:immunology*; D011817:Rabbits; D012709:Serum Albumin / Q000276:immunology; D018074:Vaccines, Conjugate
D005657:Fungal Vaccines; D007106:Immune Sera; D007074:Immunoglobulin G; D008351:Mannans; D009844:Oligosaccharides; D012709:Serum Albumin; D018074:Vaccines, Conjugate