Total protein and immunoglobulin concentrations in equine tears.

The research article investigates the concentration of different classes of immunoglobulins in horse tears and their role in ocular surface protection. The study also observes the influence of age and sex on immunoglobulin concentrations.

Key Findings

• The lacrimal fluid or tears are a vital component of the defense mechanism of the ocular surface, containing varying concentrations of all classes of immunoglobulins. These are proteins produced by the immune system that play a crucial role in fighting infections.
• This study measured four specific classes of immunoglobulins, namely IgA, IgM, IgG, and IgGT in horse tears. These immunoglobulins contribute to the immune protection of the ocular surface.
• Quantitatively, IgA constituted 50% of all lacrimal proteins, assuming the main responsibility for local protection. As seen in other species, IgA is the principal immunoglobulin in equine tears.
• Although at a lower concentration, the remaining classes of immunoglobulins – IgM, IgG, and IgGT, were also found normally present in equine tear fluid.

The Role of Sex and Age

• This research additionally reported that female and adult horses had significantly higher mean IgA concentration than male and young horses. This finding indicates a possible influence of sex and age on the immunoglobulin concentrations in tears.

Active Transport Mechanisms

• The study also suggested the presence of active transport or secretion mechanisms in relation to immunoglobulin levels in tears. The absence of a significant correlation between plasma and tear immunoglobulin levels indicated this.
• This suggested mechanism aligns with reports about the IgA immunoglobulin in other species, meaning that the immunoglobulins in tears are not merely diffused from the blood plasma but may be actively transported or secreted.