Genetic variation of envelope gp90 gene of equine infectious anemia virus isolated from an experimentally infected horse.

This research investigates the genetic variation in the envelope gene of Equine Infectious Anemia Virus (EIAV), isolated from a horse, and its influence on the virus’s stages of infection.

Objective and Methodology

• The researchers conducted an experiment where a specific strain of EIAV, P337-V70, was introduced to a horse. The infectious disease caused by this virus presents with febrile and non-febrile stages, and the researchers aimed to analyze the variations in the virus isolated during these different stages.
• The virus strains were isolated from both these stages, and then the env gp90 gene of all the strains, including the initial P337-V70 and also a benign version of the virus derived from it, known as P337-V26, were sequenced.

Findings

• Several key discoveries were revealed when the sequences of the gp90 gene were compared. Protein variations among the various virus strains analyzed amounted to between 8.2 to 11.5%.
• The most striking feature was that the virus strains isolated during the non-febrile stage of the disease were found to have nucleotide insertions in the Principal Neutralizing Domain (PND) region of the gp90 gene. These insertions were organized into smaller segments within this region.
• When comparing the original P337-V70 strain with its benign derivative P337-V26, it was found that the latter contained a six-nucleotide insertion as well as seven other nucleotide substitutions outside the PND region.

Significance

• This research sheds light on the genetic variations that occur in the EIAV during different stages of infection. Understanding the type and extent of such variations is crucial in comprehending the disease’s behavior and developing effective treatments or vaccines.
• The identification of distinct nucleotide insertions in the non-febrile stage of the virus provides critical insights into the evolution of the virus during the course of infection and how this may affect its virulence levels or provoke changes in clinical symptoms.
• The observations of changes in the gp90 gene of the benign virus strain also emphasizes the importance of this gene in the virus’s behavior and potentially in its susceptibility to neutralizing antibodies.