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Detailed characterization of transmitted HIV-1 variants in Uganda is fundamentally important to inform vaccine design, yet studies on the transmitted full-length strains of subtype D viruses are limited. Here, we amplified single genomes and characterized viruses, some of which were previously classified as subtype D by sub-genomic pol sequencing that were transmitted in Uganda between December 2006 to June 2011. Analysis of 5′ and 3′ half genome sequences showed 73% (19/26) of infections involved single virus transmissions, whereas 27% (7/26) of infections involved multiple variant transmissions based on predictions of a model of random virus evolution. Subtype analysis of inferred transmitted/founder viruses showed a high transmission rate of inter-subtype recombinants (69%, 20/29) involving mainly A1/D, while pure subtype D variants accounted for one-third of infections (31%, 9/29). Recombination patterns included a predominance of subtype D in the gag/pol region and a highly recombinogenic envelope gene. The signal peptide-C1 region and gp41 transmembrane domain (Tat2/Rev2 flanking region) were hotspots for A1/D recombination events. Analysis of a panel of 14 transmitted/founder molecular clones showed no difference in replication capacity between subtype D viruses (n = 3) and inter-subtype mosaic recombinants (n = 11). However, individuals infected with high replication capacity viruses had a faster CD4 T cell loss. The high transmission rate of unique inter-subtype recombinants is striking and emphasizes the extraordinary challenge for vaccine design and, in particular, for the highly variable and recombinogenic envelope gene, which is targeted by rational designs aimed to elicit broadly neutralizing antibodies.

Recently, Oberle et al. published a paper in Retrovirology evaluating the question of whether selection plays a role in HIV transmission. The Oberle study found no obvious genotypic or phenotypic differences between donors and recipients of epidemiologically linked pairs from the Swiss cohort. Thus, Oberle et al. characterized HIV-1 B transmission as largely "stochastic", an imprecise and potentially misleading term. Here, we re-analyzed their data and placed them in the context of transmission data for over 20 other human and animal trials. The present study finds that the transmitted/founder (T/F) viruses from the Swiss cohort show the same non-random genetic signatures conserved in 118 HIV-1, 40 SHIV, and 12 SIV T/F viruses previously published by two independent groups. We provide alternative interpretations of the Swiss cohort data and conclude that the sequences of their donor viruses lacked variability at the specific sites where other studies were able to demonstrate genotypic selection. Oberle et al. observed no phenotypic selection in vitro, so the problem of determining the in vivo phenotypic mechanisms that cause genotypic selection in HIV remains open. [ABSTRACT FROM AUTHOR]

Vaginal shedding of cytomegalovirus (CMV) DNA was determined longitudinally among 96 women coinfected with human immunodeficiency virus (HIV), herpes simplex virus 2, and CMV starting antiretroviral therapy (ART) during a placebo-controlled trial of HSV-2 suppression with acyclovir in Rakai, Uganda. Vaginal CMV was detected in 75 of 96 women (78.0%) and 379 of 1080 individual visits (35.1%). ART status, higher HIV RNAviral load before ART initiation, and younger age were significantly associated with increased frequency of CMV shedding (P < .01). Compared to pre- ART, CMV shedding peaked from month 2 to month 4 after ART initiation, suggesting possible immune reconstitution inflammatory syndrome. Further studies need to determine the clinical significance of asymptomatic CMV shedding. [ABSTRACT FROM AUTHOR]

The relevance of superinfection as a model to identify correlates of protection against human immunodeficiency virus (HIV) depends on whether the superinfecting transmission resembles primary infection, which has not been established. Here, we characterize the genetic bottleneck in superinfected individuals for the first time. In all 3 cases, superinfection produced a spike in viral load and could be traced to a single, C-C chemokine receptor 5-tropic founder virus with shorter, less glycosylated variable regions than matched chronic viruses. These features are consistent with primary HIV transmission and provide support for the use of superinfection as a model to address correlates of protection against HIV. [ABSTRACT FROM AUTHOR]

Detailed characterization of transmitted HIV-1 variants in Uganda is fundamentally important to inform vaccine design, yet studies on the transmitted full-length strains of subtype D viruses are limited. Here, we amplified single genomes and characterized viruses, some of which were previously classified as subtype D by sub-genomic pol sequencing that were transmitted in Uganda between December 2006 to June 2011. Analysis of 5′ and 3′ half genome sequences showed 73% (19/26) of infections involved single virus transmissions, whereas 27% (7/26) of infections involved multiple variant transmissions based on predictions of a model of random virus evolution. Subtype analysis of inferred transmitted/founder viruses showed a high transmission rate of inter-subtype recombinants (69%, 20/29) involving mainly A1/D, while pure subtype D variants accounted for one-third of infections (31%, 9/29). Recombination patterns included a predominance of subtype D in the gag/pol region and a highly recombinogenic envelope gene. The signal peptide-C1 region and gp41 transmembrane domain (Tat2/Rev2 flanking region) were hotspots for A1/D recombination events. Analysis of a panel of 14 transmitted/founder molecular clones showed no difference in replication capacity between subtype D viruses (n = 3) and inter-subtype mosaic recombinants (n = 11). However, individuals infected with high replication capacity viruses had a faster CD4 T cell loss. The high transmission rate of unique inter-subtype recombinants is striking and emphasizes the extraordinary challenge for vaccine design and, in particular, for the highly variable and recombinogenic envelope gene, which is targeted by rational designs aimed to elicit broadly neutralizing antibodies. [ABSTRACT FROM AUTHOR]

The relevance of superinfection as a model to identify correlates of protection against human immunodeficiency virus (HIV) depends on whether the superinfecting transmission resembles primary infection, which has not been established. Here, we characterize the genetic bottleneck in superinfected individuals for the first time. In all 3 cases, superinfection produced a spike in viral load and could be traced to a single, C-C chemokine receptor 5-tropic founder virus with shorter, less glycosylated variable regions than matched chronic viruses. These features are consistent with primary HIV transmission and provide support for the use of superinfection as a model to address correlates of protection against HIV., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)