Getting to Grips with Strangles: An Effective Multi-Component Recombinant Vaccine for the Protection of Horses from Streptococcus equi Infection

PLoS Pathogens

Andrew S. Waller¹  Carl Robinson¹  Lars Frykberg²  Bengt Guss²  Margareta Flock³  Jan-Ingmar Flock³  Ken C. Smith⁴ 

[1] Department of Bacteriology, Animal Health Trust, Lanwades Park, Kentford, Newmarket, United Kingdom;Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden;Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden;Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, United Kingdom

关键词: Ponies;    Streptococcus equi;    Mouse models;    Lymph nodes;    Horses;    Vaccination;    immunization;    Antibodies;    Vaccines;   

DOI  :  10.1371/journal.ppat.1000584

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine could confer broad protection to horses throughout the world. Welsh mountain ponies (n = 7) vaccinated with a combination of seven recombinant S. equi proteins were significantly protected from experimental infection by S. equi, resembling the spontaneous disease. Vaccinated horses had significantly reduced incidence of lymph node swelling (p = 0.0013) lymph node abscessation (p = 0.00001), fewer days of pyrexia (p = 0.0001), reduced pathology scoring (p = 0.005) and lower bacterial recovery from lymph nodes (p = 0.004) when compared with non-vaccinated horses (n = 7). Six of 7 vaccinated horses were protected whereas all 7 non-vaccinated became infected. The protective antigens consisted of five surface localized proteins and two IgG endopeptidases. A second vaccination trial (n = 7+7), in which the IgG endopeptidases were omitted, demonstrated only partial protection against S. equi, highlighting an important role for these vaccine components in establishing a protective immune response. S. equi shares >80% sequence identity with Streptococcus pyogenes. Several of the components utilized here have counterparts in S. pyogenes, suggesting that our findings have broader implications for the prevention of infection with this important human pathogen. This is one of only a few demonstrations of protection from streptococcal infection conferred by a recombinant multi-component subunit vaccine in a natural host.

【 授权许可】

CC BY