Clinical Efficacy of the HIV Protease Inhibitor Indinavir in Combination with Chemotherapy for Advanced Classic Kaposi Sarcoma Treatment: A Single-Arm, Phase II Trial in the Elderly.

Unlabelled: Kaposi sarcoma is a rare angioproliferative disease associated with human herpes virus-8 (HHV-8) infection. Kaposi sarcoma is frequent and aggressive in HIV-infected people, whereas the classic form (CKS) generally has an indolent course. Notably, all conventional therapies against Kaposi sarcoma have only temporary efficacy.

Role of HIV-1 Tat Protein Interactions with Host Receptors in HIV Infection and Pathogenesis.

Each time the virus starts a new round of expression/replication, even under effective antiretroviral therapy (ART), the transactivator of viral transcription Tat is one of the first HIV-1 protein to be produced, as it is strictly required for HIV replication and spreading. At this stage, most of the Tat protein exits infected cells, accumulates in the extracellular matrix and exerts profound effects on both the virus and neighbor cells, mostly of the innate and adaptive immune systems. Through these effects, extracellular Tat contributes to the acquisition of infection, spreading and progression to AIDS in untreated patients, or to non-AIDS co-morbidities in ART-treated individuals, who experience inflammation and immune activation despite virus suppression.

New insights into pathogenesis point to HIV-1 Tat as a key vaccine target.

Despite over 30 years of enormous effort and progress in the field, no preventative and/or therapeutic vaccines against human immunodeficiency virus (HIV) are available. Here, we briefly summarize the vaccine strategies and vaccine candidates that in recent years advanced to efficacy trials with mostly unsatisfactory results. Next, we discuss a novel and somewhat contrarian approach based on biological and epidemiological evidence, which led us to choose the HIV protein Tat for the development of preventive and therapeutic HIV vaccines.

Anti-Tat immunity defines CD4 T-cell dynamics in people living with HIV on long-term cART.

Background: Low-level HIV viremia originating from virus reactivation in HIV reservoirs is often present in cART treated individuals and represents a persisting source of immune stimulation associated with sub-optimal recovery of CD4 T cells. The HIV-1 Tat protein is released in the extracellular milieu and activates immune cells and latent HIV, leading to virus production and release. However, the relation of anti-Tat immunity with residual viremia, persistent immune activation and CD4 T-cell dynamics has not yet been defined.

HIV-1 Tat Protein Enters Dysfunctional Endothelial Cells via Integrins and Renders Them Permissive to Virus Replication.

Previous work has shown that the Tat protein of Human Immunodeficiency Virus (HIV)-1 is released by acutely infected cells in a biologically active form and enters dendritic cells upon the binding of its arginine-glycine-aspartic acid (RGD) domain to the α5β1, αvβ3, and αvβ5 integrins. The up-regulation/activation of these integrins occurs in endothelial cells exposed to inflammatory cytokines that are increased in HIV-infected individuals, leading to endothelial cell dysfunction. Here, we show that inflammatory cytokine-activated endothelial cells selectively bind and rapidly take up nano-micromolar concentrations of Tat, as determined by flow cytometry.