Higher Cytokine and Opsonizing Antibody Production Induced by Bovine Serum Albumin (BSA)-Conjugated Tetrasaccharide Related to Streptococcus pneumoniae Type 3 Capsular Polysaccharide

Abstract

A number of studies have demonstrated the limited efficacy of S. pneumoniae type 3 capsular polysaccharide (CP) in the 13-valent pneumococcal conjugate vaccine against serotype 3 invasive pneumococcal diseases and carriage. Synthetic oligosaccharides (OSs) may provide an alternative to CPs for development of novel conjugated pneumococcal vaccines and diagnostic test systems. A comparative immunological study of di–, tri–, and tetra–bovine serum albumin (BSA) conjugates was performed. All oligosaccharides conjugated with biotin and immobilized on streptavidin-coated plates stimulated production of IL-1α, IL-2, IL-4, IL-5, IL-10, IFNγ, IL-17A, and TNFα, but not IL-6 and GM-CSF in monocultured mice splenocytes. The tetrasaccharide–biotin conjugate stimulated the highest levels of IL-4, IL-5, IL-10, and IFNγ, which regulate expression of specific immunoglobulin isotypes. The tetra–BSA conjugate adjuvanted with aluminum hydroxide elicited high levels of IgM, IgG1, IgG2a, and IgG2b antibodies (Abs). Anti-CP-induced Abs could only be measured using the biotinylated tetrasaccharide. The tetrasaccharide ligand possessed the highest binding capacity for anti-OS and antibacterial IgG Abs in immune sera. Sera to the tetra–BSA conjugate promoted greater phagocytosis of bacteria by neutrophils and monocytes than the CRM197-CP-antisera. Sera of mice immunized with the tetra–BSA conjugate exhibited the highest titer of anti-CP IgG1 Abs compared with sera of mice inoculated with the same doses of di– and tri–BSA conjugates. Upon intraperitoneal challenge with lethal doses of S. pneumoniae type 3, the tri– and tetra–BSA conjugates protected mice more significantly than the di–BSA conjugate. Therefore, it may be concluded that the tetrasaccharide ligand is an optimal candidate for development of a semi-synthetic vaccine against S. pneumoniae type 3 and diagnostic test systems.

Synthetic BSA-conjugated disaccharide related to the Streptococcus pneumoniae serotype 3 capsular polysaccharide increases IL-17A Levels, γδ T cells, and B1 cells in mice

“…Antibody titers for CP in post-immunization sera were measured using ELISA. Briefly, plates coated with S. pneumoniae type 3 CP were incubated with antisera from 6 immunized mice ( 42 ). Wells were washed and secondary antibody was added, followed by incubation and washing.…”

“…The ability of semisynthetic glycoconjugates to stimulate cytokine production in vivo and their influence on the activation of cellular immunity remain unknown. Here, we report on the effect of a conjugate of the synthetic disaccharide, which represents a repeating unit of S. pneumoniae serotype 3 ( 42 ), on production of Th1/Th2/Th17 cytokines in mice, changes in expression of surface molecules on splenocytes, antibody response, and protection against S. pneumoniae infection. We also investigated the production of autoantibodies against double-stranded (ds) DNA.…”

Semi- and fully synthetic carbohydrate vaccines against pathogenic bacteria: recent developments

“…The Nifantiev laboratory conducted intensive research on semisynthetic pneumococcal glycoconjugate vaccines. A comparative immunological study of synthetic oligosaccharides of the CPS repeating units of ST3 [ 37 ] and ST14 [ 38 , 39 ] conjugated to bovine serum albumin (BSA) revealed that the optimal candidates for semisynthetic vaccines for both STs are tetrasaccharide ligands. Further immunological studies in mice revealed protective properties of both neoglycoconjugates.…”

Synthesis and immunogenicity evaluation of oligosaccharide epitopes for the development of a glycoconjugate vaccine against Streptococcus pneumoniae serotype 3

“…[14][15][16][17][18][19] Therefore, several groups have focused on the synthesis of ST3 CPS oligosaccharide fragments and the discovery of immunogenic epitopes to develop ST3 oligosaccharide-based glycoconjugate vaccines. [20][21][22][23][24][25] Vliegenthart's group prepared a series of neoglycoproteins using the synthesized ST3 CPS oligosaccharides with chain lengths varying from di-to tetra-saccharide. 21 Immunological study revealed that those ST3 oligosaccharide-CRM197 conjugates could elicit robust specific IgG antibodies to provide immunoprotection against the lethal challenges of ST3.…”