Preferential production and secretion of immunoglobulins by the equine endometrium–a mucosal immune system.

The research explores the differences in immune response in the uterine fluids of healthy and subfertile mares, noticing significant discrepancies in immunoglobulin concentration. Important to note is that a higher concentration of specific immunoglobulins in the uterus than in serum was observed.

Objective and Methodology

• The research compares the immunoglobulin concentrations found in both serum and uterine washings of mares. This is performed on two distinct sample sets – one group of 10 normal mares, and another group of 7 subfertile mares that have chronic endometrial pathology.
• The samples were collected at two different stages – during dioestrus and oestrus.
• Four different types of immunoglobulins were observed: IgA, IgG, IgG(T), and IgM. The concentrations observed were expressed as a percentage of the total immunoglobulin in the uterus or serum.
• The difference in concentrations for these immunoglobulins during the two stages were noted and compared against each group of mares.

Findings

• A significantly greater concentration of IgA was found in the uterus than in the serum.
• There were significant changes in total immunoglobulin and IgG concentrations between the dioestrus and oestrus stages in normal mares. Essentially, both were higher in dioestrus compared to oestrus.
• However, there were no significant changes observed in IgA, IgG(T), and IgM in normal mares between the two stages nor any significant changes in total immunoglobulin and other types.
• Subfertile mares displayed a significantly higher concentration of total immunoglobulins, IgA and IgG, in the uterine fluid than that found in normal mares.
• Immunoglobulins were also identified in endometrial biopsy specimens with the use of indirect immunofluorescent staining.
• IgA was observable in epithelial cells of normal mares and in the epithelial, glandular secretion, and plasma cells of subfertile mares. However, other classes of immunoglobulins were not visibly identified.

Implications

• This research provides an insight into the role of immunoglobulins in the mucosal immune system of the equine endometrium.
• The study particularly highlights the differences in immune responses within the uterine environment between normal and subfertile mares, pointing toward potential areas of further study in equine fertility issues.