Antibody isotypes in sera of equine fetuses aborted due to Leptospira interrogans serovar pomona-type kennewicki infection.

This study investigates the types of specific antibodies found in the serum of unborn horse foals that were aborted as a result of infection by a strain of Leptospira bacteria. The research found that IgM was the most common type of antibody found in both the unborn foals and their mothers, suggesting that unborn horses might not be able to produce two other types of antibodies – IgGb and IgG(T) – at sufficient levels.

Investigating Antibodies in Horses Infected with Leptospira

The researchers involved in this study were trying to understand why some pregnant mares, or female horses, were aborting their foetuses. They discovered that the cause was an infection by the Leptospira interrogans serovar pomona-type kennewicki bacteria. The study went further to compare the types of antibodies present in the serum of the unborn foals, as well as their infected mothers.

• It was found that IgM, a type of antibody, was the most common one found in both the unborn foals and the mares.
• IgGa was also found in large quantities in the sera of both the unborn foals and their mothers. However, it was detected in significantly larger quantities in foals.
• On the other hand, the presence of IgGb and IgG(T) was noticeably less in the unborn foals.

Findings on IgGa, IgGb and IgG(T) Production

The study presents evidence that indicates differences in the production of antibodies in unborn foals compared to adult horses.

• The researchers observed that while the mother horses (mares) produced IgGb in large quantities, this was not the case in their aborted fetuses.
• In addition, the sera from the mares held substantial quantities of Leptospira-specific serum IgG, especially IgG(T), IgGa, and IgGb. Unfortunately, IgG(T) and IgGb were detected in little to no quantities in the foals.
• This lack of IgGb and IgG(T) in foals led the researchers to suggest that equine fetuses may have a deficiency in producing these specific antibody isotypes.

Role of IgM in Agglutination

Additionally, the study shed light on the role of the IgM antibody in agglutinating, or clumping together, the Leptospira bacteria.

• The researchers found out that removing IgGa from the serum led to agglutination of the bacteria, implying that the IgM is the main antibody that causes this clumping process.
• This finding is significant because agglutination is one way the immune system deals with threats; by clumping organisms like bacteria together, it makes it easier for the body to eliminate them.