We report the development of a novel protein-based nasal vaccine against Streptococcus pneumoniae, in which three pneumococcal proteins were displayed on the surface of a non-recombinant, killed Lactococcus lactis-derived delivery system, called Gram-positive Enhancer Matrix (GEM). The GEM particles induced the production of the proinflammatory cytokine tumour necrosis factor-alpha (TNF-α) by macrophages as well as the maturation of dendritic cells. The pneumococcal proteins IgA1 protease (IgA1p), putative proteinase maturation protein A (PpmA) and streptococcal lipoprotein A (SlrA) were anchored in trans to the surface of the GEM particles after recombinant production of the antigens in L. lactis as hybrids with a lactococcal cell wall binding domain, named Protein Anchor domain (PA). Intranasal immunisation with the SlrA-IgA1p or trivalent vaccine combinations without additional adjuvants showed significant protection against fatal pneumococcal pneumonia in mice. The GEM-based trivalent vaccine is a potential pneumococcal vaccine candidate that is expected to be easy to administer, safe and affordable to produce.

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Keywords Gram-positive Enhancer Matrix (GEM), Nasal vaccine, Streptococcus pneumoniae
Persistent URL dx.doi.org/10.1016/j.vaccine.2006.09.026, hdl.handle.net/1765/35962
Audouy, S.A.L, Selm, S, van Roosmalen, M.L, Post, E, Kanninga, R, Neef, J, … Hermans, P.W.M. (2007). Development of lactococcal GEM-based pneumococcal vaccines. Vaccine, 25(13), 2497–2506. doi:10.1016/j.vaccine.2006.09.026