[Expression and immunogenicity of equine infectious anemia virus membrane protein GP90].

The research focused on the expression and immunogenicity of the GP90 membrane protein of the equine infectious anemia virus (EIAV), its potential for differential diagnosis and preparation for a genetically engineered vaccine.

Research Methodology

• The researchers used the Bac-to-Bac baculovirus expression system to express DLV (a vaccine strain) and LN (its parental wild type strain) of the EIAV.
• Donkey Peripheral Blood Mononuclear Cells (PBMCs) were infected with these strains and the DNA was extracted.
  These DNA templates were then used to amplify the GP90 gene variants from both strains.
• The resulting proteins were expressed using the Bac-to-Bac baculovirus expression system. This involved infecting sf9 insect cells with the recombinant baculovirus.
• The proteins expressed by this process were then purified using Immobilized Metal Affinity Chromatography (IMAC). This resulted in protein purity levels of 87% for DLV and 82% for LN strains.
• BALB/c mice were then inoculated with the purified protein and the immune response was studied. This included the specific binding Abs as determined by ELISA method and the establishment of a neutralizing assay to determine the ability of the antigens to neutralize the virus.

Research Findings

• Confirmation of viral antigens expression by the recombinant viruses was achieved using Western blotting.
• The grouping led to antibodies titers of 1,600 with an adjuvant and 800 without it.
• It was found that sera from immunized mice, when reacted with EIAV, protected 50% of donkey skin cells from a Cytopathic Effect (CPE).
• The neutralizing antibody titer was found to be in the range of 40 to 80 in animals immunized with and without the adjuvant.

Conclusions Derived from the Study

• The researchers successfully expressed EIAV vaccine strain and wild type strain membrane proteins in a eukaryotic cell expression system as planned.
• These proteins showed strong immunogenicity, indicating their potential for vaccine development.
• They were able to stimulate the production of an anti-EIAV specific antibody and a neutralizing antibody to EIAV.