SYNTHETIC CONJUGATED ANALOGUES OF CAPSULE POLYSACCHARIDES OF PNEUMOCOCCUS - AN INSTRUMENT FOR DETECTION OF POST-VACCINATION ANTIBODIES

Abstract

Aim. Evaluation of the ability of capsule polysaccharides (CP) of Streptococcus pneumoniae serotype 3 and 14 and their synthetic structure analogues, conjugated with bovine serum albumin (BSA), to detect antibodies in post-vaccination sera of mice. Materials and methods. Oligosaccharides corresponding to one, one and a half and two repeating links of serotype 3 and 14 S. pneumoniae CP were synthesized, their conjugates with BSA were produced by squarate method as well. Ligand content per BSA molecule was controlled by MALDI-TOF spectrometry. Immune sera were obtained after 2 intraperi-toneal administrations to mice of glucoconjugates adsorbed on aluminum hydroxide or 13-valent pneumococcal conjugated vaccine. Determination of levels of post-vaccination class G antibodies and their sub-isotypes was carried out in EIA. Results. Immunization of mice with neoglucoconjugates resulted in formation of predominantly IgGl recognizing serotype 3 and 14 S. pneumoniae CP. IgGl in mice immunized with a 13-valent conjugated vaccine recognized serotype 3 S. pneumoniae CP, but detected serotype 14 S. pneumoniae CP weakly. All the conjugated synthetic oligosaccharides were characterized by a high ability to bind antibodies in blood of mice immunized with the polysaccharide conjugated vaccine. BSA-tetrasaccharide of serotype 3 S. pneumoniae and BSA-tetrasaccharide of serotype 14 S. pneumoniae were characterized by the highest ability to detect IgG 1 against CP. Conclusion. Synthetic oligosaccharides, conjugated with BSA protein-carrier, may be used to develop diagnostic test-systems for determination of antibodies in post-vaccination sera.

Keywords

• capsule polysaccharide
• conjugate
• synthetic oligosaccharide
• antibody
• pneumococcus