Extensively Deleted Simian Immunodeficiency Virus (SIV) DNA in Macaques Inoculated with Supercoiled Plasmid DNA Encoding Full-Length SIVmac239

Abstract

Using long-distance DNA PCR, we prospectively followed rhesus monkeys that had been inoculated intramuscularly with supercoiled plasmid DNA encoding intact simian immunodeficiency virus (SIV). From 4 to 10 weeks postinoculation onward, we detected extensively deleted proviral genomes along with full-length viral genomes in peripheral blood mononuclear cells (PBMC) in adult macaques. During their chronic asymptomatic phase of infection, the frequency of deleted proviral genomes was similar in PBMC and lymph nodes. The latter, however, harbored significantly more full-length proviral DNA than PBMC, consistent with the lack of effective antiviral cytotoxic T-cell activity in lymph nodes described by others during human immunodeficiency virus infection. After the macaques progressed to AIDS, full-length proviral DNA became equally abundant in lymph nodes and in PBMC. We have demonstrated that although a single molecular species of proviral DNA was inoculated, genomic diversity was detected within a short time, thus confirming the genetic instability of the SIV genome in vivo.

Comparison of virology and immunology in SHIV 89.6 proviral DNA and virus‐inoculated rhesus macaques

“…Previous studies have shown that inoculation of animals with plasmids encoding a full‐length proviral genome can establish a persistent viral infection [6–8, 10–13, 18, 19, 21]. This study demonstrates that inoculation with a plasmid encoding the proviral genome for SHIV 89.6 produces a persistent viral infection in rhesus macaques.…”

“…Despite these concerns, identifying the mechanisms by which attenuated vaccines confer protection is an area of considerable interest. It has been shown previously that cats, goats, and monkeys inoculated with plasmids encoding full‐length lentivirus proviral genomes develop persistent viral infections [6–8, 11, 12, 18, 19, 21]. Based on these studies the use of full‐length lentivirus proviral plasmids as a method for live attenuated vaccine delivery is being considered [10, 13].…”

Dual Role of Prostratin in Inhibition of Infection and Reactivation of Human Immunodeficiency Virus from Latency in Primary Blood Lymphocytes and Lymphoid Tissue

“…This indicates that most of the proviral DNA in resting CD4 ϩ T cells in peripheral blood of infected patients either carries intrinsic defects precluding expression of the HIV genome or is subjected to an epigenetic control mechanism. Pion et al (35,36) and Sanchez et al (37) have previously demonstrated a high proportion of truncated proviruses in PBMC and lymph nodes of HIV-1-infected individuals and simian immunodeficiency virus-infected macaques but not in in vitro-infected CD4 ϩ T cells. Thus, the absence of selective mechanisms leading to the accumulation of defective and expression-blocked proviruses in vivo can cause the great majority of proviruses in in vitro HIV-1-infected CD4 ϩ T cells to be reactivated by prostratin or PHA.…”

Immunotherapy with DNA vaccine and live attenuated rubella/SIV gag vectors plus early ART can prevent SIVmac251 viral rebound in acutely infected rhesus macaques

“…The immunized macaques showed SIV viral blips at early timepoints, but these became infrequent over time [28]. The instability of proviral sequences as well as the low fraction of full-length proviral DNA was also shown for SIV by Pion et al [29]. These authors inoculated purified, supercoiled SIVmac239 plasmid DNA intramuscularly into rhesus macaques, which resulted in high levels of viremia.…”