Abstract
Objectives: Currently approved pneumococcal vaccines comprise only a part of the clinically relevant S. pneumoniae serotypes. Moreover, high costs limit their administration, particularly in developing countries. An innovative chemical method enables the synthesis of almost any capsular polysaccharide antigen of S. pneumoniae and thereby, a cost-efficient rapid production of polyvalent vaccines according to the clinical and epidemiological necessity. In the current pilot study, the protective effect of a new glycoconjugate vaccine consisting of a synthetic capsular oligosaccharide of S. pneumoniae serotype 3 was examined.
Methods: Mice were subcutaneously immunised with monovalent glycoconjugate with or without the adjuvant aluminium hydroxide (alum) and boosted twice at two week intervals prior to transnasal infection with S. pneumoniae serotype 3.
Results: The synthetic glycoconjugate vaccine induced the production of specific antibodies against serotype 3 capsular oligosaccharide in mice. Pneumococcal infection was associated with hypothermia and loss of body weight in non-vaccinated controls and glycoconjugate vaccinated mice, but not in mice immunised with glycoconjugate and alum. Bacterial load of lung, bronchoalveolar lavage fluid and blood was significantly decreased in mice vaccinated in combination with the adjuvant. Immunisation with glycoconjugate and alum prior to pneumococcal infection reduced cytokine release into the bronchoalveolar space and prevented damage of the endoepithelial barrier.
Conclusion: Immunisation with S. pneumoniae serotype 3 glycoconjugate protected mice from severe pneumococcal pneumonia by inducing protective antibodies.
Funding: SFB/TR84.
- © 2014 ERS