Recombinant hyaluronate associated protein as a protective immunogen against Streptococcus equi and Streptococcus zooepidemicus challenge in mice

摘要

The purified capsule of S. equi contained a protein of similar molecular mass (about 53 kDa) to a hyaluronate associated protein (HAP) from S. equisimilis. A PCR using primers derived from the published sequence of S. equisimilis HAP yielded a product from S. equi and S. zooepidemicus of the expected size and susceptibility to restriction endonucleases. Cloning fragments of the S. equi HAP gene into an expression vector, pGEX-3X, produced a GST (glutathione-S-transferase) fusion protein (HAP-GST).Anti-serum to HAP-GST caused a reduction in capsule production by S. equi cultured on blood agar. Immunization with the HAP-GST reduced rhinitis in Balb/CA mice challenged nasally with S. equi and increased survival time and clearance of bacteria in CBA/CA mice challenged intraperitoneally with S. zooepidemicus.