Control of equine infectious anemia virus is not dependent on ADCC mediating antibodies.

The research article reports that the immune control of equine infectious anemia virus (EIAV) in horses is not dependent on the presence of antibodies that perform Antibody Dependent Cellular Cytotoxicity (ADCC).

Research Objective

• The primary goal of this research was to investigate the role of ADCC mediating antibodies in controlling the EIAV in horses. This was prompted by the unexplained mechanism of how horses eventually manage to control EIAV, despite recurrent episodes of viremia (presence of viruses in the blood).

Methods and Observations

• The research discovered that horses infected with EIAV did produce antibodies within a month post-infection which targeted and latched onto the surface-exposed envelope (Env) glycoproteins of EIAV-infected cells.
• These antibodies, however, were incapable of executing ADCC when tests were conducted using EIAV-infected equine kidney (EK) cells as targets, and peripheral blood mononuclear cells (PBMC) or polymorphonuclear cells (PMN) as effector cells.
• The same observation held true when purified IgG antibodies from horses infected with either EIAV-WSU5 or EIAV-Wyo were used in carrying out ADCC on infected target cells. No armed effector cells could be found in the blood of infected horses, nor could these effector cells be prearmed by incubation with serum antibodies to cell surface antigens.

Comparison and Result

• The research further reinforced its findings by drawing a contrast with the equine herpesvirus 1 (EHV-1). Serum antibody from EHV-1 vaccinated horses and PBMC or PMN as effector cells were able to cause ADCC of EHV-1-infected EK cells.
• This difference in reaction indicated that the immune control of EIAV in horses was not vested in ADCC. Hence, antibodies mediating ADCC were not responsible for the eventual control of EIAV in horses.