Localised mitogenic activity in horses following infection with Streptococcus equi.

This research investigates the presence and areas of activity of superantigens (sAg) in horses infected with Streptococcus equi, the bacterium responsible for a severe upper respiratory disease, strangles. The study indicated that sAg activity occurs in abscesses and chondroids during both infection and carrier phases of the disease.

Introduction

• The research focuses on understanding the superantigens (sAgs) in Streptococcus equi subspecies equi (S. equi), the source of strangles, a highly infectious upper respiratory ailment in horses. S. equi generates superantigens, considered to contribute to disease pathogenicity through non-specific T-cell activation and a pro-inflammatory response.
• S. equi infection causes abscesses in the head and neck lymph nodes. However, some abscess material can persist in the guttural pouch and form chondroids over time, which can house live S. equi.

Aim of the Study

• The research aims to identify the sites of sAg production during an infection to further our understanding of their role. The knowledge could be instrumental in dealing with strangles and could create possibilities for improved management and treatment strategies.

Methods

• The study involved the collection of abscess material, chondroids, and serum from the Equidae (the horse family) members showing signs of strangles. These were tested in mitogenic assays, a method to measure the increase in the number of cells in a tissue, to trace the presence and activity of sAgs.

Results and Conclusion

• The results revealed the presence of mitogenic sAg activity only in abscess material and chondroids. This outcome underscores that sAg activity is localized during both the acute and carrier stages of S. equi infection.
• These findings enhance the understanding of strangles pathogenesis and the role of sAgs, which could have implications for developing more effective treatments and preventive measures against the disease.