Genetic identity and biological phenotype of a transmitted/founder virus representative of nonpathogenic simian immunodeficiency virus infection in African green monkeys.
Understanding the lack of disease progression in nonpathogenic simian immunodeficiency virus (SIV) infections is essential for deciphering the immunopathogenesis of human AIDS. Yet, in vivo studies have been hampered by a paucity of infectious molecular clones (IMCs) of SIV suitable to dissect the viral and host factors responsible for the nonpathogenic phenotype. Here, we describe the identification, cloning, and biological analysis of the first transmitted/founder (T/F) virus representing a nonpathogenic SIV infection. Blood was collected at peak viremia from an acutely infected sabaeus monkey (Chlorocebus sabaeus) inoculated intravenously with an African green monkey SIV (SIVagm) strain (Sab92018) that had never been propagated in vitro. To generate IMCs, we first used conventional (bulk) PCR to amplify full-length viral genomes from peripheral blood mononuclear cell (PBMC) DNA. Although this yielded two intact SIVagmSab genomes, biological characterization revealed that both were replication defective. We then performed single-genome amplification (SGA) to generate partially overlapping 5' (n = 10) and 3' (n = 13) half genomes from plasma viral RNA. Analysis of these amplicons revealed clusters of nearly identical viral sequences representing the progeny of T/F viruses. Synthesis of the consensus sequence of one of these generated an IMC (Sab92018ivTF) that produced infectious CCR5-tropic virions and replicated to high titers in Molt-4 clone 8 cells and African green monkey PBMCs. Sab92018ivTF also initiated productive infection in sabaeus monkeys and faithfully recapitulated the replication kinetics and nonpathogenic phenotype of the parental Sab92018 strain. These results thus extend the T/F virus concept to nonpathogenic SIV infections and provide an important new tool to define viral determinants of disease nonprogression.
Gnanadurai
Clement Wesley
CW
Institute of Molecular Virology, University Clinic of Ulm, Ulm, Germany.
Pandrea
Ivona
I
Parrish
Nicholas F
NF
Kraus
Matthias H
MH
Learn
Gerald H
GH
Salazar
Maria G
MG
Sauermann
Ulrike
U
Töpfer
Katharina
K
Gautam
Rajeev
R
Münch
Jan
J
Stahl-Hennig
Christiane
C
Apetrei
Christian
C
Hahn
Beatrice H
BH
Kirchhoff
Frank
F
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016663:Cercopithecinae; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D018450:Disease Progression; D005434:Flow Cytometry; D016679:Genome, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D010641:Phenotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D016097:Simian Acquired Immunodeficiency Syndrome / Q000235:genetics* / Q000503:physiopathology; D015302:Simian Immunodeficiency Virus / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D014779:Virus Replication / Q000502:physiology
D017931:DNA Primers