Hepatitis C virus infection (HCV) represents a unique model to characterize, from early to late stages of infection, the T cell differentiation process leading to exhaustion of human CD8+ T cells. Here we show that in early HCV infection, exhaustion-committed virus-specific CD8+ T cells display a marked upregulation of transcription associated with impaired glycolytic and mitochondrial functions, that are linked to enhanced ataxia-telangiectasia mutated (ATM) and p53 signaling. After evolution to chronic infection, exhaustion of HCV-specific T cell responses is instead characterized by a broad gene downregulation associated with a wide metabolic and anti-viral function impairment, which can be rescued by histone methyltransferase inhibitors. These results have implications not only for treatment of HCV-positive patients not responding to last-generation antivirals, but also for other chronic pathologies associated with T cell dysfunction, including cancer.

Long-lived resting memory CD4+ T cells (TCM) are a major reservoir of latent HIV infection. We hypothesized that latent HIV-TCM cells are maintained by aberrant expression of cell survival factors, including XIAP, BIRC2/cIAP1, and beclin-1. DIABLO/SMAC mimetics are therapeutic agents that compromise cell survival by hijacking host apoptotic machinery. We found that DIABLO/SMAC mimetics (birinapant, GDC-0152, and embelin) selectively kill HIV-TCM without increasing virus production or targeting uninfected TCM. Treatment of HIV-TCM with DIABLO/SMAC mimetics promoted XIAP and BIRC2 degradation, which triggered autophagy and the formation of a cell death complex consisting of pro-apoptotic (FADD, RIPK1, RIPK3, and caspase 8) and autophagy (ATG5, ATG7, and SQSTM1) proteins. Genetic or pharmacological inhibition of autophagy induction, but not autophagy-mediated degradation, abrogated this interaction and subsequent cell death. Our findings identify a mechanism whereby DIABLO/SMAC mimetics exploit autophagy and apoptotic machinery to selectively induce killing of HIV-TCM without viral reactivation while sparing uninfected cells.
Copyright © 2018 Elsevier Inc. All rights reserved.

Several small-molecule Bruton tyrosine kinase (BTK) inhibitors are in development for B cell malignancies and autoimmune disorders, each characterized by distinct potency and selectivity patterns. Herein we describe the pharmacologic characterization of BTK inhibitor acalabrutinib [compound 1, ACP-196 (4-[8-amino-3-[(2S)-1-but-2-ynoylpyrrolidin-2-yl]imidazo[1,5-a]pyrazin-1-yl]-N-(2-pyridyl)benzamide)]. Acalabrutinib possesses a reactive butynamide group that binds covalently to Cys481 in BTK. Relative to the other BTK inhibitors described here, the reduced intrinsic reactivity of acalabrutinib helps to limit inhibition of off-target kinases having cysteine-mediated covalent binding potential. Acalabrutinib demonstrated higher biochemical and cellular selectivity than ibrutinib and spebrutinib (compounds 2 and 3, respectively). Importantly, off-target kinases, such as epidermal growth factor receptor (EGFR) and interleukin 2-inducible T cell kinase (ITK), were not inhibited. Determination of the inhibitory potential of anti-immunoglobulin M-induced CD69 expression in human peripheral blood mononuclear cells and whole blood demonstrated that acalabrutinib is a potent functional BTK inhibitor. In vivo evaluation in mice revealed that acalabrutinib is more potent than ibrutinib and spebrutinib. Preclinical and clinical studies showed that the level and duration of BTK occupancy correlates with in vivo efficacy. Evaluation of the pharmacokinetic properties of acalabrutinib in healthy adult volunteers demonstrated rapid absorption and fast elimination. In these healthy individuals, a single oral dose of 100 mg showed approximately 99% median target coverage at 3 and 12 hours and around 90% at 24 hours in peripheral B cells. In conclusion, acalabrutinib is a BTK inhibitor with key pharmacologic differentiators versus ibrutinib and spebrutinib and is currently being evaluated in clinical trials.
Copyright © 2017 by The Author(s).

Redirecting T cells to attack cancer using engineered chimeric receptors provides powerful new therapeutic capabilities. However, the effectiveness of therapeutic T cells is constrained by the endogenous T cell response: certain facets of natural response programs can be toxic, whereas other responses, such as the ability to overcome tumor immunosuppression, are absent. Thus, the efficacy and safety of therapeutic cells could be improved if we could custom sculpt immune cell responses. Synthetic Notch (synNotch) receptors induce transcriptional activation in response to recognition of user-specified antigens. We show that synNotch receptors can be used to sculpt custom response programs in primary T cells: they can drive a la carte cytokine secretion profiles, biased T cell differentiation, and local delivery of non-native therapeutic payloads, such as antibodies, in response to antigen. SynNotch T cells can thus be used as a general platform to recognize and remodel local microenvironments associated with diverse diseases.
Copyright © 2016 Elsevier Inc. All rights reserved.

SIV model indicates that upon traversing the cervicovaginal mucosa, SIV/SIV-infected cells migrate to regional lymph nodes where active replication occurs prior to systemic virus dissemination. The purpose of the study is to develop a model to study early HIV-1 transmission events that occur after crossing the cervical mucosa into regional lymph nodes.
We developed an organ culture model combining intact cervical tissue explants and tonsil tissue cells as the surrogate draining lymphoid tissue. Viral replication was measured by HIV-1 p24 production, quantification of viral DNA and viral RNA expression in tonsil cells.
In this combined organ culture model, transmission of cell-free and cell-associated R5- and X4-tropic HIV-1 through the cervical mucosa to tonsilar cells was observed as determined by HIV-1 p24 in culture supernatant, and the presence of HIV-1 proviral DNA, HIV-1 p24 gag protein in CD4(+) , CD11c(+) , CD68(+) cells, and expression of HIV-1 mRNA expressing CD45RO(+)  CD4 T cells in tonsil cells. Furthermore, co-receptor usage of HIV-1 in tonsil cells correlated with inoculating virus tropism.
Our combined cervix-tonsil organ culture could serve as an experimental model to study the earliest stages of HIV-1 transmission through cervicovaginal mucosa to its proximal lymph nodes.
© 2012 John Wiley & Sons A/S.