Streptococcus pyogenes is a Gram-positive bacterial pathogen of humans. It causes a broad range of diseases from self-limiting throat and skin infections to life-threatening conditions such as streptococcal toxic shock syndrome and rheumatic heart disease resulting in over 500 000 deaths annually. Global efforts have been aimed at the development of a vaccine using a range of delivery techniques. Skin-based micro-array patches have shown promising results with advantages over intramuscular delivery which include dose sparing, enhanced thermostability, reduced sharp waste and ease of use.
We evaluated the M-protein-based vaccine candidate, J8-DT, delivered by a high density micro-array patch (HD-MAP). J8-DT coated on a HD-MAP (J8-DT/HD-MAP), retained immunogenic properties and induced similar total IgG responses to that generated by vaccination with intramuscular J8-DT adjuvanted with Alum (J8-DT/Alum).
Following skin infection in a murine model, J8-DT/HD-MAP vaccination led to a significant reduction in the number of S. pyogenes colony forming units in skin (93.27%) and blood (100%) compared to the naïve control mice. The protection profile was comparable to that of intramuscular J8-DT/Alum. J8-DT/HD-MAP induced a shift in the antibody isotype profile, with a bias towards Th1-related isotypes, compared to J8-DT/Alum (Th2 bias). The results from this study provide evidence that the use of J8-DT/HD-MAP should be considered in future clinical development and control programs against S. pyogenes.