Evaluation of the immune response and protective effects of rhesus macaques vaccinated with biodegradable nanoparticles carrying gp120 of human immunodeficiency virus.

We previously reported that biodegradable amphiphilic poly(gamma-glutamic acid) nanoparticles (NPs) carrying the recombinant gp120 env protein of the human immunodeficiency virus type 1 (HIV-1) were efficiently taken up by dendritic cells, and induced strong CD8(+) T cell responses against the gp120 in mice. To evaluate gp120-carrying NPs (gp120-NPs) as a vaccine candidate for HIV-1 infection, we vaccinated rhesus macaques with these gp120-NPs and examined the immune response and protective efficacy against a challenge inoculation of simian and human immunodeficiency chimeric virus (SHIV). We found that gp120-NP vaccination induced stronger responses for both gp120-specific cellular and humoral immunity than gp120-alone vaccination. After the challenge inoculation with SHIV, however, the peak value of viral RNA in the peripheral blood was higher in the vaccinated groups, especially the gp120-NP vaccinated group, than naive control group. Higher value of viral load was also maintained in gp120-NP vaccinated group. Furthermore, CD4(+) T cells from the peripheral blood decreased more in the vaccinated groups than the control group. Thus, induced immune responses against gp120 enclosed in NPs were not effective for protection but, conversely enhanced the infection, although the gp120-NPs showed a stronger induction of immune responses against the vaccinated antigen in rhesus macaques. These results support the importance of determining immune correlate of protective immunity for vaccine development against HIV-1 infection.

In vivo analysis of a new R5 tropic SHIV generated from the highly pathogenic SHIV-KS661, a derivative of SHIV-89.6.

Although X4 tropic SHIVs have been studied extensively, they show distinct infection phenotypes from those of R5 tropic viruses, which play an important role in HIV-1 transmission and pathogenesis. To augment the variety of R5 tropic SHIVs, we generated a new R5 tropic SHIV from the highly pathogenic X4 tropic SHIV-KS661, a derivative of SHIV-89.6. Based on consensus amino acid alignment analyses of subtype B R5 tropic HIV-1, five amino acid substitutions in the third variable region successfully changed the secondary receptor preference from X4 to R5. Improvements in viral replication were observed in infected rhesus macaques after two passages, and reisolated virus was designated SHIV-MK38. SHIV-MK38 maintained R5 tropism through in vivo passages and showed robust replication in infected monkeys. Our study clearly demonstrates that a minimal number of amino acid substitutions in the V3 region can alter secondary receptor preference and increase the variety of R5 tropic SHIVs.

Small intestine CD4+ cell reduction and enteropathy in simian/human immunodeficiency virus KS661-infected rhesus macaques in the presence of low viral load.

Human immunodeficiency virus type 1, simian immunodeficiency virus and simian/human immunodeficiency virus (SHIV) infection generally lead to death of the host accompanied by high viraemia and profound CD4(+) T-cell depletion. SHIV clone KS661-infected rhesus macaques with a high viral load set point (HVL) ultimately experience diarrhoea and wasting at 6-12 months after infection. In contrast, infected macaques with a low viral load set point (LVL) usually live asymptomatically throughout the observation period, and are therefore referred to as asymptomatic LVL (Asym LVL) macaques. Interestingly, some LVL macaques exhibit diarrhoea and wasting similar to the symptoms of HVL macaques and are termed symptomatic LVL (Sym LVL) macaques. This study tested the hypothesis that Sym LVL macaques have the same degree of intestinal abnormalities as HVL macaques. The proviral DNA loads in lymphoid tissue and the intestines of Sym LVL and Asym LVL macaques were comparable and all infected monkeys showed villous atrophy. Notably, the CD4(+) cell frequencies of lymphoid tissues and intestines in Sym LVL macaques were remarkably lower than those in Asym LVL and uninfected macaques. Furthermore, Sym LVL and HVL macaques exhibited an increased number of activated macrophages. In conclusion, intestinal disorders including CD4(+) cell reduction and abnormal immune activation can be observed in SHIV-KS661-infected macaques independent of virus replication levels.

Inhibition of human immunodeficiency virus type 1 (HIV-1) nuclear import via Vpr-Importin alpha interactions as a novel HIV-1 therapy.

The development of multidrug-resistant viruses compromises the efficacy of anti-human immunodeficiency virus (HIV) therapy and limits treatment options. Therefore, new targets that can be used to develop novel antiviral agents need to be identified. One such target is the interaction between Vpr, one of the accessory gene products of HIV-1 and Importin alpha, which is crucial, not only for the nuclear import of Vpr, but also for HIV-1 replication in macrophages. We have identified a potential parent compound, hematoxylin, which suppresses Vpr-Importin alpha interaction, thereby inhibiting HIV-1 replication in a Vpr-dependent manner. Analysis by real-time PCR demonstrated that hematoxylin specifically inhibited nuclear import step of pre-integration complex. Thus, hematoxylin is a new anti-HIV-1 inhibitor that targets the nuclear import of HIV-1 via the Vpr-Importin alpha interaction, suggesting that a specific inhibitor of the interaction between viral protein and the cellular factor may provide a new strategy for HIV-1 therapy.

Small intestine CD4+ T cells are profoundly depleted during acute simian-human immunodeficiency virus infection, regardless of viral pathogenicity.

To analyze the relationship between acute virus-induced injury and the subsequent disease phenotype, we compared the virus replication and CD4(+) T-cell profiles for monkeys infected with isogenic highly pathogenic (KS661) and moderately pathogenic (#64) simian-human immunodeficiency viruses (SHIVs). Intrarectal infusion of SHIV-KS661 resulted in rapid, systemic, and massive virus replication, while SHIV-#64 replicated more slowly and reached lower titers. Whereas KS661 systemically depleted CD4(+) T cells, #64 caused significant CD4(+) T-cell depletion only in the small intestine. We conclude that SHIV, regardless of pathogenicity, can cause injury to the small intestine and leads to CD4(+) T-cell depletion in infected animals during acute infection.

Whole genome sequence data of an infectious molecular clone of the SIVagm TYO-1 strain.

We first sequenced a full genome of simian immunodeficiency virus isolated from African green monkey (SIVagm) but the clone sequenced was found not to be biologically active. We subsequently succeeded in reconstructing a full genome infectious molecular clone, named pSA212. The infectious pSA212 clone (known as the TYO-1 strain of SIVagm) has been distributed widely for research analysis of SIVagm but its genome has never been fully sequenced. Here, we report the whole genome sequence of the infectious pSA212.