Immunoglobulin coating in healthy dogs and dogs with chronic enteropathy

Canine chronic enteropathies (CE) constitute a group of disorders that cause chronic gastrointestinal tract inflammation and persistent or recurrent gastrointestinal signs in dogs. Immunoglobulins (Igs) are part of the adaptive immune system and constitute crucial arms that directly influence the function and structure of the microbiota. In people and mice, relative levels of bacterial coating with Igs might be predicted to correlate with the magnitude of the inflammatory response triggered by specific intestinal bacterial species. The aim of the study is to characterise immunoglobulin A and G-coated faecal bacteria in healthy dogs and in dogs with chronic enteropathies over time using flow cytometry, bacterial cell sorting and 16S RNA sequencing. We found that the percentage of Ig coating was higher during active disease compared to the remission period but was similar to healthy dogs. In addition, the type of bacteria coated with Igs presented high instability over the course of the disease and was individual-specific in CE dogs, whereas, in healthy dogs, the bacterial coating presented short-term stability.