HIV This Week

Worobey M, Gemmel M, Teuwen DE, Haselkorn T, Kunstman K, Bunce M, Muyembe JJ, Kabongo JM, Kalengayi RM, Van Marck E, Gilbert MT, Wolinsky SM. Direct evidence of extensive diversity of HIV-1 in Kinshasa by 1960. Nature. 2008 Oct 2;455(7213):661-4.

Human immunodeficiency virus type 1 (HIV-1) sequences that pre-date the recognition of AIDS are critical to defining the time of origin and the timescale of virus evolution. A viral sequence from 1959 (ZR59) is the oldest known HIV-1 infection. Other historically documented sequences, important calibration points to convert evolutionary distance into time, are lacking, however; ZR59 is the only one sampled before 1976. Here Worobey et al report the amplification and characterization of viral sequences from a Bouin's-fixed paraffin-embedded lymph node biopsy specimen obtained in 1960 from an adult female in Léopoldville, Belgian Congo (now Kinshasa, Democratic Republic of the Congo (DRC)), and they use them to conduct the first comparative evolutionary genetic study of early pre-AIDS epidemic HIV-1 group M viruses. Phylogenetic analyses position this viral sequence (DRC60) closest to the ancestral node of subtype A (excluding A2). Relaxed molecular clock analyses incorporating DRC60 and ZR59 date the most recent common ancestor of the M group to near the beginning of the twentieth century. The sizeable genetic distance between DRC60 and ZR59 directly demonstrates that diversification of HIV-1 in west-central Africa occurred long before the recognized AIDS pandemic. The recovery of viral gene sequences from decades-old paraffin-embedded tissues opens the door to a detailed palaeovirological investigation of the evolutionary history of HIV-1 that is not accessible by other methods.

Editors’ note: This is like a detective story which starts with finding old specimens from Kinshasa that both contain HIV and are in good enough shape for analysis. This genetic sequencing comparison reveals that HIV-1 group M, which still exists as a natural reservoir in chimpanzees in the same region, likely crossed species near the beginning of the 20 th century. Rather than fading away, HIV in humans then may have taken off with the founding and growth of colonial administrative and trading centres like Kinshasa. Further work on the evolutionary history of HIV could yield important insights into the pathogenesis, virulence, and evolution of HIV.