Antigenic polysaccharides present on the surface of the cell wall of myco- and bacterial pathogens play an important role at various stages of their biological recognition. In this regard, synthetic oligosaccharide ligands, structurally related to the polysaccharides of the cell wall of infectious agents, are a convenient basis for the development of specific vaccines and diagnostics for pathogen detection and control of vaccination efficiency [1,2]. This report discusses the main stages in the development of 3rd generation carbohydrate vaccines (synthetic conjugate vaccines). The original methods of stereospecific synthesis of oligosaccharides developed in our laboratory made it possible to obtain preparative amounts of oligosaccharide ligands corresponding to immunodeterminant fragments of bacterial and fungal antigens. Thus, using the pyranoside-into-furanoside rearrangement discovered by our team [3], we obtained oligosaccharides related to polysaccharides of bacteria (Klebsiella pneumonia [4,5], Enterococcus faecalis [6]), as well as fungal pathogens (Aspergillus fumigatus [7-9]). The resulting oligosaccharides allow of detailed characterization of the carbohydrate specificity of antibodies against pathogens [10,11], and then create conjugated candidate vaccines that make it possible to induce protective antibodies that prevent infections [6], including those caused by antibiotic-resistant strains of hospital infections.

Conflicts of Interest:
The authors declare that they have no conflict of interest in the publication of this article. The authors have no conflicts of interest to report in this work. Abstract was not submitted elsewhere and published here firstly.

Funding:
This work was supported by the Ministry of Science and Higher Education of the Russian Federation (Theme No. FFZZ-2022-0010) for new laboratories in the direction of "New Medicine"