Distinct evolutionary pressures underlie diversity in simian immunodeficiency virus and human immunodeficiency virus lineages

Will Fischer, Cristian Apetrei, Mario L. Santiago, Yingying Li, Rajeev Gautam, Ivona Pandrea, George M. Shaw, Beatrice H. Hahn, Norman L. Letvin, Gary J. Nabel, Bette T. Korber

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Simian immunodeficiency virus (SIV) infection of rhesus macaques causes immune depletion and disease closely resembling human AIDS and is well recognized as the most relevant animal model for the human disease. Experimental investigations of viral pathogenesis and vaccine protection primarily involve a limited set of related viruses originating in sootymangabeys (SIVsmm). The diversity of human immunodeficiency virus type 1 (HIV-1) has evolved in humans in about a century; in contrast, SIV isolates used in the macaque model evolved in sooty mangabeys over millennia. To investigate the possible consequences of such different evolutionary histories for selection pressures and observed diversity in SIVsmm andHIV-1, we isolated, sequenced, and analyzed 20 independent isolates of SIVsmm, including representatives of 7 distinct clades of viruses isolated from natural infection. We found SIVsmm diversity to be lower overall than HIV-1 M group diversity. Reduced positive selection (i.e., less diversifying evolution) was evident in extended regions of SIVsmm proteins, most notably in Gag p27 and Env gp120. In addition, the relative diversities of proteins in the two lineages were distinct: SIVsmm Env and Gag were much less diverse than their HIV-1 counterparts. This may be explained by lower SIV-directed immune activity in mangabeys relative to HIV-1-directed immunity in humans. These findings add an additional layer of complexity to the interpretation and, potentially, to the predictive utility of the SIV/macaque model, and they highlight the unique features of human and simian lentiviral evolution that inform studies of pathogenesis and strategies for AIDSvaccine design.

Original languageEnglish (US)
Pages (from-to)13217-13231
Number of pages15
JournalJournal of Virology
Issue number24
StatePublished - Dec 2012
Externally publishedYes

ASJC Scopus subject areas

  • Immunology
  • Virology


Dive into the research topics of 'Distinct evolutionary pressures underlie diversity in simian immunodeficiency virus and human immunodeficiency virus lineages'. Together they form a unique fingerprint.

Cite this