Primate models for human immunodeficiency virus infection. Evolution of receptor use during pathogenesis

Pharmacologic opportunities for HIV prevention

Innovations in antiretroviral (ARV) treatment strategies have resulted in treated HIV-infected patients having life expectancies similar to those of uninfected individuals. Yet the number of individuals capable of HIV transmission is increasing-for every person in whom ARV treatment is initiated, four others are becoming newly infected with HIV. The limited progress with microbicides and vaccines for HIV prevention reinforce the need for a concentrated exploration of the utility of ARVs. Preliminary animal studies with topical and systemic ARVs show promising results. However, current clinical trials were designed without a comprehensive understanding of ARV pharmacokinetic-pharmacodynamic relationships in HIV prevention. This review focuses on current strategies for the prevention of HIV infection and on the ways in which the tools of pharmacology can be a valuable resource for determining pharmacodynamic targets, providing interspecies scaling of exposures, identifying the optimal drugs/drug combinations, doses, and dosing regimens, and designing efficient clinical trials.

Variable region 4 of SIV envelope correlates with rapid disease progression in morphine-exposed macaques infected with SIV/SHIV

We analyzed the association between the evolution of the V3-V5 regions of env and disease progression in our SIV/SHIV macaque model of morphine dependence and AIDS. Previous studies revealed two distinct disease patterns--fast progression and normal progression. To determine the effect of the two distinct patterns of disease in the evolution of SIV/17E-Fr envelope, we analyzed env sequences from three morphine-dependent macaques that developed accelerated AIDS and three morphine-dependent macaques that developed AIDS at a slower rate and compared them to control macaques. Morphine-dependent animals exhibited a higher percentage of diversity in both plasma and CSF compartments within V4 when compared to controls. Divergence from the inoculum was significantly greater in the morphine group as compared to controls in CSF but not in plasma. We also found a direct correlation in V4 evolution and rapid disease progression. These results indicate that morphine dependence plays a role in the pathogenesis of SIV/SHIV infection and env evolution.

Cross-clade protection induced by human immunodeficiency virus-1 DNA immunogens expressing consensus sequences of multiple genes and epitopes from subtypes A, B, C, and FGH

The correlate of protection in human immunodeficiency virus (HIV) infection is not known, but preclinical and clinical studies support the involvement of both antibodies and cellular immunity. In addition, the existence of multiple HIV clades makes HIV vaccine design especially challenging. We have constructed a vaccine platform with an HIV-1 subtype B DNA immunogen expressing full length consensus sequences from HIV-1 rev, nef, tat, and gag with additional cellular epitope clusters from the env and pol regions. Furthermore, this platform has been extended to three additional plasmids expressing the same immunogens but originating from subtypes A or C consensus or FGH ancestral sequences. Immunogenicity in BALB/c mice, by gene gun or intramuscular delivery, revealed strong IFN-gamma production in response to in vitro re-stimulation with a H-2d restricted gag peptide (AMQMLKETI) or even stronger toward an env epitope (RGPGRAFVTI). Weak humoral immunity was detected. Gene gun immunization with a cocktail of all four plasmids induced pre-challenge cellular immunity in C57Bl6/A2.01 mice and subsequently a robust frequency of protection (11/12 animals) after experimental challenge with subtype A or B HIV-1/Murine Leukemia Virus (HIV-1/MuLV). The cross-clade protection observed in this challenge experiment demonstrates that these multigene/multiepitope HIV DNA immunogens are likely to be potent immunogens also against the HIV-infection of human beings.