Characterization of Carbohydrate Specificity of Monoclonal Antibodies to Fungal Antigenic Markers Using Biotinylated Oligosaccharides as Coating Antigens

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Marina L. Gening¹, Alina V. Polyanskaya¹, Anton N. Kuznetsov¹, Alexandra D. Titova¹, Viktor I. Yudin¹, Dmitry V. Yashunskiy², Yury E. Tsvetkov², Olga N. Yudina², Vadim B. Krylov^1,a*, Nikolay E. Nifantiev^2,b*

¹Laboratory of Synthetic Glycovaccines, N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia

²Laboratory of Glycoconjugate Chemistry, N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia

^* To whom correspondence should be addressed.

Received: September 30, 2024; Revised: October 21, 2024; Accepted: October 24, 2024

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Mannan and β-(1→3)-glucan are two polysaccharide markers that are characteristic for a number of fungal pathogens, including Candida albicans, which is the most common cause of invasive mycoses in humans. In this study, we examined epitope specificity of two monoclonal antibodies, CM532 and FG70, which recognize certain oligosaccharide fragments of these fungal polysaccharides. Using a panel of biotinylated oligosaccharides as coating antigens, we found that the CM532 antibody obtained by immunization with the pentamannoside β-Man-(1→2)-β-Man-(1→2)-α-Man-(1→2)-α-Man-(1→2)-α-Man KLH conjugate, selectively recognizes the trisaccharide β-Man-(1→2)-α-Man-(1→2)-α-Man epitope. Another antibody, FG70, obtained by immunization with heptaglucan β-Glc-(1→3)-[β-Glc-(1→3)]₅-β-Glc conjugate with KLH, interacts with the linear β-(1→3)-linked pentaglucoside fragment, and presence of 3,6-branches within this epitope does not significantly affect the interaction efficiency. The data obtained indicate that the monoclonal antibodies under consideration could be used to create effective diagnostics for detection of fungal infections, which are not available at present.

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KEY WORDS: fungal diseases, β-(1→3)-glucan, α-mannan, β-mannan, monoclonal antibodies, carbohydrate specificity, oligosaccharides

DOI: 10.1134/S0006297924120083

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