Immunological studies of Burkholderia multivorans O-antigen oligosaccharide-rsScpA193 conjugates as potential candidates for vaccine development

Int J Biol Macromol. 2024 Dec 7:138570. doi: 10.1016/j.ijbiomac.2024.138570. Online ahead of print.

Abstract

The Burkholderia cepacia complex (Bcc) is a group of phenotypically similar but genotypically diverse Gram-negative bacteria that pose a significant threat to public health worldwide. Due to the absence of effective therapies, the development of an effective vaccine against Bcc infections is urgently needed. Lipopolysaccharides (LPSs) O-antigens of B. multivorans (BM) are attractive immunogenic components and recognized as potential target antigens for vaccine development. In this study, we designed and prepared three BM oligosaccharide-based glycoconjugates rsScpA193-1-3 with rsScpA193 as a new carrier protein. We performed preliminarily immunological assessments to determine the immunogenicity of these glycoconjugates, alongside in vitro evaluations of their capacity to bind BM cells and trigger long-term immunological memory. Our findings revealed that these synthesized conjugates, especially rsScpA193-1, which exhibited stronger immunogenicity and better recognition to trisaccharide 1 and nonasaccharide 3 than the other two groups. Moreover, rsScpA193-1 could effectively bind to BM cells in vitro and successfully induce long-lasting immunological memory. Therefore, trisaccharide 1 was identified as an effective antigenic target, and the conjugate rsScpA193-1 may represent a promising candidate for BM vaccine development. Overall, our study presented the first exploitation of immunogenicity of BM oligosaccharide-protein conjugates and significantly paved the way for Bcc vaccine development.

Keywords: Burkholderia multivorans; Glycoconjugate; O-antigens; Oligosaccharide hapten; rsScpA193 protein.