Multiple specificities of immunoglobulin M in equine fetuses infected with Leptospira interrogans indicate a competent immune response.

The research investigated the immune response of horse fetuses to infection by a specific bacteria, Leptospira interrogans, and found evidence to suggest that this immune response may contribute towards the survival of these fetuses in infected mares.

Overview of the Research

• The researchers explored an outbreak of abortions in horses, caused by Leptospira interrogans serovar Pomona type kennewicki (Lk).
• The objective was to discover if the survival of fetuses is partially due to their immune response to the
  antigens of this bacteria.
• They conducted an investigation of this outbreak and a larger case-control study that included samples from aborted fetuses.
• The techniques used for diagnosing infection included serology and a polymerase chain reaction on the urine and amniotic fluids of the horses.

Findings of the Research

• In the outbreak, five fetuses out of 11 survived in utero despite persistent placental infection and were healthy when born.
• However, the fetuses of six mares were either aborted or died soon after birth.
• A significant increase in immunoglobulin (Ig)M reactivity with all of the recombinant proteins and the Lk sonicate was observed in 54 archived fluids from fetuses infected with Leptospira compared to fluids from 30 uninfected fetuses.
• Low levels of specific IgGa and IgGb for certain proteins were found in a minority of archived fluids from infected fetuses.

Conclusion of the Research

• The findings suggest that although the ability to respond to Leptospira infection majorly involves IgM, the high level of immune competence displayed by aborted fetuses is driven by the variety of proteins targeted by their immune systems.
• This immune response is likely to play a role in the survival of fetuses in infected mares.

This study provides crucial insights into the immune response dynamics of equine fetuses when confronted with Leptospira infection, and how this might contribute to their survival. It could influence future strategies for managing Leptospora outbreaks in horse populations.