Group B Streptococcus (GBS), a commensal organism, can turn into a life-threatening pathogen in neonates and elderly, or in adults with severe underlying diseases such as diabetes. We developed a
vaccine targeting the GBS
glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic
enzyme detected at the bacterial surface, which was proven to be effective in a neonatal mouse model of
infection. Since this bacterium has emerged as an important pathogen in non-pregnant adults, here we investigated whether this
vaccine also confers protection in an adult susceptible and in a diabetic mouse model of
infection. For immunoprotection studies,
sham or immunized adult mice were infected with GBS serotype Ia and V strains, the two most prevalent serotypes isolated in adults.
Sham and vaccinated mice were also rendered diabetic and infected with a serotype V GBS strain. For toxicological (pre-clinical) studies, adult mice were vaccinated three times, with three concentrations of recombinant GAPDH adjuvanted with Allydrogel, and the toxicity parameters were evaluated twenty-four hours after the last immunization. For the stability tests, the
vaccine formulations were maintained at 4°C for 6 and 12 months prior immunization. The results showed that all tested doses of the
vaccine, including the stability study formulations, were immunogenic and that the
vaccine was innocuous. The organs (brain, blood, heart, and liver) of vaccinated susceptible or diabetic adult mice were significantly less colonized compared to those of control mice. Altogether, these results demonstrate that the GAPDH-based
vaccine is safe and stable and protects susceptible and diabetic adult mice against GBS
infections. It is therefore a promising candidate as a global
vaccine to prevent GBS-induced neonatal and adult diseases.