In vivo evolution of the gp90 gene and consistently low plasma viral load during transient immune suppression demonstrate the safety of an attenuated equine infectious anemia virus (EIAV) vaccine.
To study the in vivo evolution of the attenuated Chinese equine infectious anemia virus (EIAV) vaccine, viral gp90 gene variation and virus replication in immunosuppressed hosts were investigated. The results showed that after vaccination, the gp90 gene followed an evolutionary trend of declining diversity. The trend coincided with the maturation of immunity to EIAV, and eventually, the gp90 gene became highly homologous. The sequences of these predominant quasispecies were consistently detected up to 18 months after vaccination. Furthermore, after transient immune suppression with dexamethasone, the plasma viral RNA copy number of the vaccine strain in three vaccinated ponies remained consistently below the "pathogenic threshold" level, while the viral load increased by 25,000-fold in the positive control of an inapparent carrier of the parental virulent strain. This study is the first to provide evidence for the safety of an attenuated lentiviral vaccine with decreased genomic diversity and consistently low viral replication under suppressed immunity.
Ma
Jian
J
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Jiang
Chenggang
C
Lin
Yuezhi
Y
Wang
Xuefeng
X
Zhao
Liping
L
Xiang
Wenhua
W
Shao
Yiming
Y
Shen
Rongxian
R
Kong
Xiangang
X
Zhou
Jianhua
J
D000818:Animals; D004859:Equine Infectious Anemia / Q000276:immunology / Q000517:prevention & control*; D005814:Genes, Viral; D006023:Glycoproteins / Q000235:genetics*; D006736:Horses / Q000821:virology; D007165:Immunosuppression Therapy; D004860:Infectious Anemia Virus, Equine / Q000235:genetics* / Q000276:immunology* / Q000502:physiology; D009154:Mutation; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D014613:Vaccines, Attenuated / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics*; D019562:Viral Load; D014765:Viral Vaccines / Q000276:immunology*; D014779:Virus Replication
D006023:Glycoproteins; D012367:RNA, Viral; C091940:SU protein, equine infectious anemia virus; D014613:Vaccines, Attenuated; D014759:Viral Envelope Proteins; D014765:Viral Vaccines