Early establishment of a pool of latently infected, resting CD4(+) T cells during primary HIV-1 infection

Abstract

The presence of latently infected, resting CD4(+) T cells carrying replication-competent HIV-1 has been demonstrated in chronically infected individuals who are antiretroviral therapy naive as well as in those who are receiving highly active antiretroviral therapy (HAART). It is not clear, however, whether the establishment of a pool of latently infected CD4(+) T cells can be blocked by early initiation of HAART after primary infection. The present study demonstrates that initiation of HAART in infected individuals as early as 10 days after the onset of symptoms of primary HIV-1 infection did not prevent generation of latently infected, resting CD4(+) T cells carrying integrated HIV-1 DNA as well as infectious HIV-1 despite the successful control of plasma viremia shortly after institution of HAART. Furthermore, there was no correlation between either the duration of HAART at the time of study (range: 0.2-17 months) or the time of initiation of HAART after the onset of symptoms of primary HIV-1 infection (range: 0.3-4 months) and the frequencies of resting CD4(+) T cells carrying either integrated HIV-1 DNA or infectious virus. These results underscore the rapidity with which latent reservoirs are established in primary HIV-1 infection and indicate that it is unlikely that early treatment during primary infection can prevent establishment of a pool of latently infected, resting CD4(+) T cells as long as treatment is initiated after plasma viremia becomes evident.

Figures

Figure 1

Time course of changes in plasma HIV-1 RNA after time of infection and initiation of HAART. The zero time point is taken as the day on which infected individuals experienced initial symptoms of HIV-1 infection (black arrows). The time of the initiation of HAART is indicated by gray arrows. The dashed line indicates the limit of detection of the assay (50 copies of HIV-1 RNA/ml plasma).

Figure 2

Frequencies of resting CD4+ T cells carrying various forms of HIV-1 DNA as well as infectious virus in infected individuals who received HAART for varying durations of times after primary infection. Frequencies of resting CD4+ T cells carrying total (A) and integrated (B) HIV-1 DNA are shown. The copy numbers of HIV-1 DNA including both unintegrated and integrated HIV-1 DNA in purified resting CD4+ T cells in infected individuals were calculated as described above. The frequencies of resting CD4+ T cells with integrated HIV-1 DNA were determined by Alu-LTR PCR by using serially diluted genomic DNA from resting CD4+ T cells. Frequencies of resting CD4+ T cells carrying replication-competent HIV-1 DNA were determined by activating purified resting CD4+ T cells on day 0 (C). Frequencies of resting CD4+ T cells carrying persistent, replication-competent HIV-1 DNA were determined by activating 6-day preincubated cells in the absence of activating stimuli (D). For each assay, the statistical method of Myers et al. was used to calculate copy numbers or infectious units per million resting CD4+ T cells (27).

Figure 3

Frequencies of resting CD4+ T cells carrying various forms of HIV-1 DNA as well as infectious virus in infected individuals in whom HAART was initiated at various times after the onset of symptoms of primary HIV-1 infection. Frequencies of resting CD4+ T cells carrying total (A) and integrated (B) HIV-1 DNA are shown. The copy numbers of HIV-1 DNA including both unintegrated and integrated HIV-1 DNA in purified resting CD4+ T cells in infected individuals were calculated as described above. The frequencies of resting CD4+ T cells with integrated HIV-1 DNA were determined by Alu-LTR PCR by using serially diluted genomic DNA from resting CD4+ T cells. Frequencies of resting CD4+ T cells carrying replication-competent HIV-1 DNA were determined by activating purified resting CD4+ T cells on day 0 (C). Frequencies of resting CD4+ T cells carrying persistent-replication competent HIV-1 DNA were determined by activating 6-day preincubated cells in the absence of activating stimuli (D). For each assay, the statistical method of Myers et al. was used to calculate copy numbers or infectious units per million resting CD4+ T cells (27).