K. pneumoniae is an encapsulated, Gram-negative, non-motile bacterium that forms part of the normal gut microbiota. These commensal microorganisms rarely cause infection in healthy individuals. However, in immunocompromised individuals with severe comorbidities, K. pneumoniae can invade other tissues from the gastrointestinal tract and oral cavity, causing pneumonia, sepsis, meningitis, liver abscess, urinary tract infection, and many other diseases.
In recent decades, genetic variants have emerged that enhance K. pneumoniae's resistance to many antimicrobials or hypervirulence in healthy individuals, such as highly virulent multidrug-resistant strains (MDR) emerging in the community. K. pneumoniae clinical isolates usually show increased production of capsules and siderophores and produce one or more β-lactamases such as extended-spectrum β-lactamase (ESBL). These enzymes hydrolyze beta-lactam antibiotics, rendering them ineffective. Therefore, the researchers have turned to the development of a vaccine to prevent K. pneumoniae infection.
Fig.1 Vaccine strategies tested against K. pneumoniae. (Assoni, et al., 2021)
CD BioGlyco is a professional Glyco™ Vaccine Development company, providing clients with Carbohydrate, Glycoprotein, and Glycopeptide-based vaccine development services. Capsular polysaccharides (CPS) are present in the outermost layer of bacterial cells and are composed of straight-chain or branched-chain oligosaccharides. It directly participates in the interaction between the bacteria and the external environment and also protects the bacteria against harsh environments or harmful substances. It is one of the most important virulence factors of K. pneumoniae. To date, 77 K. pneumoniae CPS (K antigens) have been defined. Each type differs structurally from the others by the repeating polysaccharide unit of the CPS. The study found that passive immunization with antibodies against CPS protects mice from sepsis and pneumonia. Therefore, CPS-based vaccines have the potential to prevent K. pneumoniae infection.
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Fig.2 Conjugation technologies of polysaccharides and carrier proteins. (CD BioGlyco)
CD BioGlyco provides clients with high-quality K. pneumoniae CPS antigen production services. However, the high variability of CPS components greatly affects the coverage of the vaccine, making it unable to promote T cell-dependent immune responses, which in turn affects the efficacy of the vaccine. To help clients enhance T cell-dependent immune responses, we conjugate CPS polysaccharides with protein carriers. For example, we conjugate K. pneumoniae CPS with diphtheria toxin to induce specific antibodies in mice.CD BioGlyco is committed to providing clients with the highest quality and most comprehensive Polysaccharide Antigen Production services. In the past few years, we have helped many clients solve their difficulties and problems in the production of polysaccharide antigens. Please feel free to contact us for more information about polysaccharide antigen production.
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