Protective effect of vaccination with recombinant proteins from Streptococcus equi subspecies equi in a strangles model in the mouse

A mouse model resembling Streptococcus equi subspecies equi infection in the horse, strangles, was used to assess the protective effect of vaccination with selected recombinant proteins from S. equi subsp. equi. After challenge the infection was monitored by weight loss and by nasal colonisation with S. equi subsp. equi. Vaccination with a collagen-binding protein (CNE) and a collagen-like protein (SclC) resulted in protective antibodies, whereas a novel fibronectin-binding protein (FNEB) did not. Co-administration of CNE with EAG, a poorly immunogenic α 2-macroglobulin-, albumin- and immunoglobulin G-binding protein, resulted in a significant synergistic effect and enhanced the protective immune response against EAG.