Antibodies in plasma and blood cells of horses

Understanding the distribution of antibodies in the bloodstream is critical for advancing diagnostic and therapeutic approaches in veterinary medicine and comparative immunology. While most studies have focused on plasma antibodies, the presence and role of membrane-bound immunoglobulins remain underexplored, particularly in equine species such as the Jabe horse.

This study aimed to analyze the amount of antibodies in the plasma and blood cells of Jabe horses for their potential future use.

Blood samples were collected from Jabe horses and separated into plasma and cellular components. A specific technique was developed to isolate immunoglobulins from both plasma and blood cell membranes. The concentrations of different immunoglobulin classes [IgA , IgM, IgE, IgG, and Immunoglobulin D (IgD)] were measured using ELISA. Aged erythrocytes were given special attention to examine antibody accumulation over time.

The antibody concentration in plasma was generally higher than that on blood cell membranes. However, the membrane-bound fractions of IgA, IgM, and IgE ranged from 106% to 139.7%, indicating a significant membrane association. IgG levels in the supernatant were >60% lower than those in the plasma, suggesting selective membrane binding or sequestration. Notably, IgD was predominantly membrane-bound, with concentrations many times higher than those in the supernatant. A marked increase in membrane-bound immunoglobulins was observed in aged erythrocytes, highlighting a possible age-dependent accumulation. Furthermore, the content of other membrane-associated proteins correlated with their plasma concentrations.

The study reveals that immunoglobulins are not only present in plasma but are also significantly associated with blood cell membranes in Jabe horses. The high levels of membrane-bound IgD and the accumulation of antibodies on aged erythrocytes suggest that functional or regulatory roles are yet to be fully understood. The newly proposed method for antibody isolation from both plasma and cellular fractions opens opportunities for further immunological research and potential clinical applications in veterinary medicine.