Peer-reviewed veterinary case report
How does immune suppression affect EIAV in horses?
By Craigo, Jodi K et al.·Published in Virology·2006·Department of Molecular Genetics and Biochemistry, United States·View original on PubMed →
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Original publication title: Apparent elimination of EIAV ancestral species in a long-term inapparent carrier.
- Species:
- horse
Plain-English summary
In a study of horses, researchers looked at a virus called equine infectious anemia virus (EIAV) that can cause long-term infections. They took a horse that had been carrying the virus without showing symptoms and gave it a medication called dexamethasone to weaken its immune system. This led to a huge increase in the amount of virus in the horse's blood, and the researchers found that the virus was changing and evolving into new forms. They discovered that the original virus and earlier versions were no longer detectable, suggesting that the horse's immune system had successfully eliminated many of the virus's variants, but the virus continued to survive by constantly changing. Overall, the treatment showed that while the immune system can clear some virus types, the virus can still persist by evolving.
Abstract
Equine infectious anemia virus (EIAV) envelope variation produces newly dominant quasispecies with each sequential disease cycle; new populations arise, and previous plasma quasispecies, including the original inoculum, become undetectable. The question remains whether these ancestral variants exist in tissue reservoirs or if the immune system eliminates quasispecies from persistent infections. To examine this, an EIAV long-term inapparent carrier was immune suppressed with dexamethasone. Immune suppression resulted in increased plasma viral loads by approximately 10(4) fold. Characterization of pre- and post-immune suppression populations demonstrated continual envelope evolution and revealed novel quasispecies distinct from defined populations from previous disease stages. Analysis of the tissue and plasma populations post-immune suppression indicated the original infectious inoculum and early populations were undetectable. Therefore, the host immune system apparently eliminated a diverse array of antigenic variants, but viral persistence was maintained by relentless evolution of new envelope populations from tissue reservoirs in response to ongoing immune pressures.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/16226288/