Immunochemical and Conformational Properties of Structurally Defined Homo-oligo-β- <scp>d</scp> -glucosides: Examples of Gradual and Extremal Length Dependences

The profile of natural antibodies present in human serum serves as an informative indicator of various diseases, vaccination history, immune system status, and even dietary habits of patients. The ability to provide detailed and precise interpretation of this data opens opportunities for the development of new diagnostic methods and vaccines. The application of synthetic oligosaccharides as antigens with distinct structures appears promising for obtaining reproducible results in immunological screenings. In this study, we analyzed the immunochemical reactivity, NMR spectra, and conformational behavior of oligomeric β-(1→2)-, β-(1→3)-, and β-(1→6)-d-glucosides, which are structurally related to well-known pathogen-associated molecular glycopatterns. β-(1→2)-Glucooligosaccharides were found to differ fundamentally from the other two β-glucans, exhibiting unusual extremal length dependencies in immunochemical properties, nonequivalence of glycosidic linkages within the homo-β-(1→2)-glucoside chain in the NMR spectra, and the formation of stable helical conformational states within MD simulations. The immunochemical features of β-(1→2)-glucosides revealed in this study provide a basis for the development of highly specific diagnostic assays based on the detection of β-(1→2)-glucan antigens as well as the corresponding complementary antibodies.