Immunohistochemical detection of virulence-associated Rhodococcus equi antigens in pulmonary and intestinal lesions in horses.

The research investigates the effectiveness of a specific antibody in detecting a pathogen called Rhodococcus equi in horses, which can cause pulmonary and intestinal diseases. The method is deemed potentially useful in diagnosing infections, even without additional laboratory testing.

Methodology and Samples

• The researchers used two horses infected with Rhodococcus equi for the study. These animals were examined post-mortem.
• An immunohistochemical method called peroxidase-antiperoxidase (PAP) was used for the examination. This technique uses antibodies to detect specific antigens in tissues.
• Monoclonal antibody 10G5 (Mab 10G5), which is directed against a specific 15-17 kDa antigen of R. equi, was the main reagent of interest.

Findings

• Immunolabelling with Mab 10G5 was found to be extensive and noticeable in the infected tissues.
• Besides, one of the horses was also examined using bacteriological methods, in which R. equi was successfully grown in culture.

Comparison with Another Antibody

• The researchers also compared the reactivity of infected macrophages (a type of immune cell) with a polyclonal antibody specific for lysozyme, another part of the immune response.
• The reactivity with this polyclonal antibody was weaker compared to Mab 10G5.

Implications

• The findings suggest that Mab 10G5 could be a beneficial diagnostic reagent or tool in detecting R. equi infection in horses.
• This could be useful even without further cultural confirmation, which means it could provide a faster and simpler way of diagnosing such infections.