A platform for glycoengineering a polyvalent pneumococcal bioconjugate vaccine using E. coli as a host

Area of Science:

• Vaccinology
• Microbiology
• Biotechnology

Background:

• Chemical synthesis of conjugate vaccines is complex.
• In vivo bacterial conjugations (bioconjugations) offer an alternative manufacturing method.
• Existing enzymes are unsuitable for polysaccharides with glucose at the reducing end (~75% of Streptococcus pneumoniae).

Purpose of the Study:

• To develop a novel bioconjugation strategy for conjugate vaccine production.
• To overcome limitations of current oligosaccharyltransferases for specific polysaccharide structures.
• To establish a platform for generating pneumococcal bioconjugate vaccines.

Main Methods:

• Utilized an O-linking oligosaccharyltransferase for bioconjugation.
• Generated polyvalent pneumococcal bioconjugate vaccines.
• Employed E. coli for rapid recombinant production.

Main Results:

• Successfully generated bioconjugate vaccines with glucose-containing polysaccharides.
• Demonstrated glycosylation of various vaccine carrier proteins.
• Pneumococcal bioconjugates were immunogenic and protective.

Conclusions:

• Established a proof-of-principle for a new bioconjugation platform.
• Overcame limitations of existing conjugating enzymes.
• Enables development of bioconjugate vaccines for diverse pathogens.