Antibody isotyping and cytokine profiling in natural cases of Burkholderia mallei infection (glanders) in equines.

This research investigated the immune responses to the B. mallei infection, glanders, in horses, mules, and donkeys by measuring their antibody and cytokine responses. Antibodies are a type of protein that the immune system produces in response to harmful substances called antigens, while cytokines are small proteins that are key to cellular signaling in the immune response. The study identified high concentrations of specific types of antibodies and cytokines in infected equine serum, which suggests that these play an important role in the combat against B. mallei infection.

Methodology

• For this study, serum samples were taken from 151 equines that were tested positive for glanders, including 134 horses, 16 mules, and 1 donkey.
• Indirect ELISA, a commonly used method to detect specific antibodies, was used to determine IgM, IgG, IgA, and IgG (T) titre against specific recombinant antigens found in B. mallei.
• Commercial ELISA kits were used to measure the concentration of specific cytokines: interleukin(IL)-1β, IL-17, IL-6, tumor necrosis factor alpha(TNF-α), monocyte chemoattractant protein 1 (MCP-1), and interferon gamma (IFN-γ).

Findings

• The study found that glanders-affected equines produced a strong antibody response against one of the measured proteins, Hcp1.
• Moderate responses were found against other proteins, TssA and TssB.
• However, weak responses were detected against two complex proteins, PilA-Hcp1-TssN-BipD and BpaB-BpaC-T2SS.
• Among the studied cytokines, IL-1β, MCP-1, IL-17, and IL-6 concentration were significantly higher in glanders-affected equine serum.

Conclusion

• The results revealed that IgG antibody titre was higher than others, and Hcp1 was the most predominant antibody inducers in comparison to others.
• The study found that the high levels of IL-1β, MCP-1, IL-17, IL-6, IFN-γ, and TNF-α in the serum could contribute to enhancing the cellular defense by recruiting important immune cells against B. mallei infection.
• The researchers recommend further studies to investigate memory cell responses in natural cases of equine glanders using recombinant B. mallei proteins. This will provide valuable insights for the development of effective and well-characterized vaccines against this disease.