Contribution of naive CD4+T cells to the intact HIV reservoir

Background: Recent findings suggest that na€ıve CD4 + T cells (TN) may contain a significant amount of replication-competent HIV DNA. We studied the contribution of different CD4 + T-cell subsets to the reservoir in two male Caucasian subjects on ART at approximately two and nine years after ART initiation, both virologically suppressed at the time of the donations.Methods: We sorted T CD4 + subsets from CD3 + CD8- PBMCs, defined as follows: na€ıve (CD45RA+, CCR7+, CD27+), central memory (CD45RA, CCR7+, CD27+), transitional memory (CD45RA, CCR7, CD27+), and effector memory (CD45RA, CCR7, CD27). Wemeasured total HIV DNA and sequenced 890 and 513 near full- length proviruses for Subject 1 and 2, respectively.Results: Among the subsets TN showed the highest percentage of intact proviruses. The contribution of TN to the intact reservoir was stable overtime, representing 38.5 and 34.7% for Subject 1 and 58.7 and 58.3% for Subject 2 at the two timepoints. The intact proviral sequences appeared to be mostly unique in TN while mostly clonal in effector memory cells (Figure 1).Conclusions: TN appear to contribute significantly to the intact reser- voir in two subjects followed on ART for nearly one decade.After reducing the clones, even a greater fraction of the reservoir was har- bored in TN. Given their long half-life and lower metabolic activity, the TN reservoir may represent a unique hurdle to HIV eradication. A limitation of our study is that the sorted TN population is a mixture of na€ıve, stem cell memory and T cells that have divided. In our opinion to sequence two individuals deeply at two time points provided us a better understanding of reservoir dynamics within subsets. Moreover, these individuals represent a spectrum of HIV infection. Subject 1 is a slow progressor with only CCR5-tropic proviruses while Subject 2 is a rapid progressor with a majority of CXCR4-tropic proviruses.