The emergence of drug resistance is a serious threat to the long-term virologic success and durability of HIV-1 therapy. Adherence has been shown to be a major determinant of drug resistance; however, each pharmacologic class of antiretroviral drugs has a unique adherence–resistance relationship. We develop an immunological model of the HIV-1 infected human immune system that integrates the unique mechanisms of action of reverse transcriptase and protease inhibiting drugs. A system of impulsive differential equations is used to examine the drug kinetics within CD4⁺ T cells. Stability analysis was preformed to determine the long-term dynamics of the model. Using the endpoints of an impulsive periodic orbit in the drug levels, the maximal length of a drug holiday while avoiding drug resistance is theoretically determined; the minimum number of doses that must be subsequently taken to return to pre-interruption drug levels is also established. Heterogeneity in inter-individual differences on drug-holiday length is explored using sensitivity analysis based on Latin Hypercube Sampling and Partial Rank Correlation Coefficient analysis. Extremely short drug holidays are acceptable, as long as they are followed by a period of strict adherence. Numerical simulations demonstrate that if the drug holiday exceeds these recommendations, the cost in virologic rebound is unacceptably high. These theoretical predictions are in line with clinical results and may also help form the basis of future clinical trials.

La tri-thérapie utilisée pour le traitement du VIH-1 est efficace mais limitée par l'apparition de résistances. Par conséquent, des cibles virales alternatives sont nécessaires. Une des cibles les plus prometteuses est la protéine nucléocapside (NC), qui est hautement conservée et qui joue un rôle essentiel dans le cycle viral. Dans ce contexte, le projet européen THINPAD a eu pour but de développer des inhibiteurs de la NC en combinant plusieurs approches : criblage virtuel, criblage secondaire in vitro, tests antiviraux et de toxicité. Pour le criblage in vitro, nous avons utilisé le test de déstabilisation de cTAR, hautement spécifique de l’activité chaperonne de NC. Cinq séries de molécules ont été sélectionnées par les premiers criblages et tests antiviraux. Après des études de relation structure-activité, une seule des cinq séries a été poursuivie jusqu’aux tests d'efficacité chez les souris. Les composés de cette série présentent une activité antivirale à des concentrations nanomolaires, mais ne sont pas actifs dans le modèle murin. Les études de mécanisme d'action ont révélés que leur activité antivirale était bien consécutive au ciblage de la NC. / Highly Active Anti-Retroviral Therapy (HAART) is successfully used for HIV-1 treatment, but is hampered by the appearance of drug resistance. Thereby, alternative drug targets are required. One of the most promising target is the nucleocapsid protein (NC), which is highly conserved and plays essential role in HIV life cycle. In this context, the European project THINPAD was organized with the aim to develop NC inhibitors. To fulfil this objective, several approaches were used, including virtual screening, in vitro secondary screening, in cellulo antivirals tests, and toxicity evaluation. For in vitro screening, the specific NC-promoted cTAR destabilization assay was used. Five series of molecules were selected by the first screenings and antiviral tests. After structure-activity relationship studies, only one series was continued until efficacy testing in mice. The compounds of this series exhibit antiviral activity at nanomolar concentrations but are not active in the murine model. The mechanisms of action studies revealed that their antiviral activity was indeed consecutive to the targeting of the NC.

Albert Font Haro ABSTRACT Modulation of plasmacytoid dendritic cell function: role of immunoreceptors TIM-3 and BDCA-2 Plasmacytoid dendritic cells (pDCs) are key players in the antiviral response as well as in linking innate and adaptive immune response. They express endosomal toll-like receptors 7 and 9, which can detect ssRNA and unmethylated CpG DNA, respectively. Due to the constitutive expression of the transcription factor IRF7, pDCs are able to rapidly produce massive quantities of type I (α, β, ω) and type III (1, 2, 3, 4) interferons (IFN-I and IFN-III) as well as pro- inflammatory cytokines such as IL-1, IL-6 and TNF-α. After maturation, they also function as antigen-presenting cells. Despite intense research, the mechanisms of IFN and pro-inflammatory cytokines production and regulation are still poorly understood. Using the pDC cell line GEN2.2 and also primary human pDCs, we shed light on the role of kinases MEK and SYK in IFN-I production and regulation. We found that SYK is not only involved in the regulatory receptor (RR)-mediated BCR-like pathway that represents the negative regulation of IFN-I and IFN-III secretion but also in the positive TLR7/9-mediated signal transduction pathway that leads to IFN-I production, representing the immunogenic function. We also found that MEK plays a...