mDAPTA, a potent CCR5 receptor blocker, prevents viral recovery from CD8-depleted patient PBMCs with VL< 50 background
Elimination
of the treatment resistant persistent viral reservoir is an important treatment
goal. Monitoring the size and replicative-competence of HIV reservoirs has
been indicated as a means for measuring the efficacy of drug treatments. An
enhanced culture method using stimulation of CD8-depleted PBMCs produces
an effective means by which virus can be cultured from Clinically Relevant
Cellular Compartment (CRCC). We have shown that, monomeric
D-Ala-Peptide-T-amide (mDAPTA), an R5 entry inhibitor eliminated persistent
monocyte infection in 11 patients. This study reports a novel finding that
mDAPTA prevents HIV recovery and production of replication-competent HIV from
CD8-depleted patient PBMCs.
Methods: CD8-depleted PBMCs were
isolated from HIV-negative and positive donors with VL< 50 RNA. PBMCs were
then subjected to virus rescue using activation by anti-CD28/CD3 in presence or
absence of CCR5 inhibitors DAPTA and Maraviroc. Virus was quantitated
using TZMbl as reporter cells and by p24 assays.
Results: Replication competent
virus (R5 and X4) was generated in 4 HIV patients CD8-depleted PBMCs when
no drug was added to the cultures. Interestingly, we found that DAPTA (0.1pm)
completely inhibited the release of virus (X4 and R5) from PBMCs from all
patients in vitro. DAPTA's effect on inhibiting X4 replication was primarily
via modulating activation. Maraviroc only worked at the level of virus
entry. DAPTA was 1000 times more potent than maraviroc in inhibiting
virus entry. Currently we are investigating the virological outcome to detect
infectious virus with mDAPTA in a large cohort of infected individuals.
Conclusions: Our findings demonstrate strongly that mDAPTA prevents
viral rebound/recovery from CD8-depleted patient PBMCs by blocking CCR5
entry and cellular activation thus preventing virus release from CRCC.
Moreover patients with X4 viruses that fail to show significant virological
benefit after receiving CCR5-inhibitors which primarily target CCR5 may benefit
from DAPTA treatment. Thus DAPTA is an effective blocker of virus release and
cellular activation.
L. Agrawal1, O. Ducoudret1, N. Baichoo1, M. Laznicka2, M. Ruff1, C. Pert1
1Rapid Laboratories, Rockville, United States, 2Rapid Pharmaceuticals, Rigistrasse, Switzerland