The Influence of Different Cucumariosides on Immunogenicity of OmpF Porin from Yersinia Pseudotuberulosis as a Model Protein Antigen of Tubular Immunostimulating Complex

摘要

Nanoparticulate tubular immunostimulating complex (TI-complex) is a novel promising adjuvant carrier of antigens allowing to create safe and effective vaccines of new generation. The adjuvant activity of TI-complexes based on monogalactosyldyacylglycerol (MGDG) from the sea alga Ulva lactuca and different triterpene glycosides cucumariosides (CDs) from marine invertebrate Cucumaria japonica and their fractions was studied to assess effects of different CDs on the immunogenicity of porin OmpF from Yersinia pseudotuberculosis (YOmpF). TI-complexes with cucumarioside A_2-2 (CDA_2-2) maximally stimulated anti-porin antibody production. Studies of protein intrinsic fluorescence showed that all CDs had a relaxing effect on the conformation of YOmpF, loosening peripheral region of protein and promoting exposure of the protein antigenic determinants to the water environment. The greatest immunostimulating effect of TI-complexes comprising CDA_2-2 was accompanied by mild effect of this CD on the tertiary structure of protein antigen YOmpF, whereas cucumarioside E (CDE) and cucumarioside A_2-4 (CDA_2-4) caused especially sharp redistribution of spectral form of the YOmpF corresponding to the emission of an intrinsic protein fluorophore tryptophan.