West and East Lealman, FL, United States
West and East Lealman, FL, United States

Time filter

Source Type

Jakobsen M.R.,University of Aarhus | Olagnier D.,Vaccine and Gene Therapy Institute of Florida | Hiscott J.,Vaccine and Gene Therapy Institute of Florida
Current Opinion in HIV and AIDS | Year: 2015

Purpose of review: The innate immune system plays a critical role in the control of viral infections. Although the mechanisms involved in sensing and response to viral pathogens has progressed tremendously in the last decade, an understanding of the innate antiviral response to human retroviruses lagged behind. Recent studies now demonstrate that human retroviruses such as human immunodeficiency virus type 1 (HIV-1) and human T-lymphotropic virus 1 (HTLV-1) trigger a type I interferon antiviral response through novel cytosolic sensors that detect DNA intermediates of reverse transcription; in addition, these early host-pathogen interactions may trigger cell death pathways depending on the activation state of the target cell. The purpose of this review is to summarize the recent progress in the understanding of innate immune sensing of human retroviruses. Recent findings: Innate immune sensing of HIV-1 and HTLV-1 is influenced by the target cell phenotype, viral replicative intermediates, and host restriction factors that limit retroviral replication. Macrophages and dendritic cells detect HIV-DNA intermediates, whereas CD4+ T cells differentially sense HIV DNA depending on the level of T-cell activation. Furthermore, the structure of the viral capsid and interplay between innate DNA sensors and host restriction factors all contribute to the magnitude of the ensuing innate immune response. Summary: The interplay between HIV infection and the innate immune system has emerged as an important component of HIV pathogenesis, linked to both induction of innate immunity and stimulation of cell death mechanisms. Ultimately, an in-depth knowledge of the mechanisms of innate immune control of human retrovirus infection may facilitate the development of novel treatment strategies to control retrovirus-induced immunopathology. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.


Katlama C.,University Pierre and Marie Curie | Deeks S.G.,University of California at San Francisco | Autran B.,University Pierre and Marie Curie | Martinez-Picado J.,Autonomous University of Barcelona | And 8 more authors.
The Lancet | Year: 2013

Antiretroviral therapy for HIV infection needs lifelong access and strict adherence to regimens that are both expensive and associated with toxic effects. A curative intervention will be needed to fully stop the epidemic. The failure to eradicate HIV infection during long-term antiretroviral therapy shows the intrinsic stability of the viral genome in latently infected CD4T cells and other cells, and possibly a sustained low-level viral replication. Heterogeneity in latently infected cell populations and homoeostatic proliferation of infected cells might affect the dynamics of virus production and persistence. Despite potent antiretroviral therapy, chronic immune activation, inflammation, and immune dysfunction persist, and are likely to have important effects on the size and distribution of the viral reservoir. The inability of the immune system to recognise cells harbouring latent virus and to eliminate cells actively producing virus is the biggest challenge to finding a cure. We look at new approaches to unravelling the complex virus-host interactions that lead to persistent infection and latency, and discuss the rationale for combination of novel treatment strategies with available antiretroviral treatment options to cure HIV. Copyright © 2013 Elsevier B.V.


Yu H.,Beckman Research Institute | Lee H.,Beckman Research Institute | Herrmann A.,Beckman Research Institute | Buettner R.,Beckman Research Institute | Jove R.,Vaccine and Gene Therapy Institute of Florida
Nature Reviews Cancer | Year: 2014

The Janus kinases (JAKs) and signal transducer and activator of transcription (STAT) proteins, particularly STAT3, are among the most promising new targets for cancer therapy. In addition to interleukin-6 (IL-6) and its family members, multiple pathways, including G-protein-coupled receptors (GPCRs), Toll-like receptors (TLRs) and microRNAs were recently identified to regulate JAK-STAT signalling in cancer. Well known for its role in tumour cell proliferation, survival, invasion and immunosuppression, JAK-STAT3 signalling also promotes cancer through inflammation, obesity, stem cells and the pre-metastatic niche. In addition to its established role as a transcription factor in cancer, STAT3 regulates mitochondrion functions, as well as gene expression through epigenetic mechanisms. Newly identified regulators and functions of JAK-STAT3 in tumours are important targets for potential therapeutic strategies in the treatment of cancer. © 2014 Macmillan Publishers Limited. All rights reserved.


Ahlers J.D.,Vaccine and Gene Therapy Institute of Florida
Discovery Medicine | Year: 2014

HIV-1 broadly neutralizing antibodies (BNAbs) develop after several years of infection through a recursive process of memory B cell adaptation and maturation against co-evolving virus quasispecies. Advances in single-cell sorting and memory B cell antibody cloning methods have identified many new HIV BNAbs targeting conserved epitopes on the HIV envelope (env) protein. 3D crystal structures and biophysical analyses of BNAbs bound to invariant virus structures expressed on monomeric gp120, epitope scaffolds, core structures, and native trimers have helped us to visualize unique binding interactions and paratope orientations that have been instrumental in guiding vaccine design. A paradigm shift in the approach to structure-based design of HIV-1 envelope immunogens came recently after several laboratories discovered that native viral envelopes or "env-structures" reverse-engineered to bind with high affinity to a handful of broadly neutralizing antibodies did not in fact bind the predicted germline precursors of these broadly neutralizing antibodies. A major challenge for HIV-1 B cell vaccine development moving forward is the design of new envelope immunogens that can trigger the selection and expansion of germline precursor and intermediate memory B cells to recapitulate B cell ontogenies associated with the maturation of a broadly neutralizing antibody response. Equally important for vaccine development is the identification of delivery systems, prime-boost strategies, and synergistic adjuvant combinations that can induce the magnitude and quality of antigen-specific T follicular helper (TFH) cell responses needed to drive somatic hypermutation (SHM) and B cell maturation against heterologous primary virus envelopes. Finding the combination of multi-protein envelope immunogens and immunization strategies that can evolve a potent broadly neutralizing antibody response portends to require a complex vaccine regimen that might be difficult to implement on any scale. This perspective strives to integrate recent insights into mechanisms associated with the evolution of an HIV-1 broadly neutralizing antibody response with current immunogen design and proffers a novel immunization strategy for skewing TH17/TFH cell responses that can drive B cell adaptation and affinity maturation associated with a broadly neutralizing antibody response. © Discovery Medicine.


Kirchenbaum G.A.,Vaccine and Gene Therapy Institute of Florida | Ross T.M.,Vaccine and Gene Therapy Institute of Florida
Current Opinion in Immunology | Year: 2014

Antibodies recognizing the hemagglutinin (HA) protein, which are elicited following infection or vaccination, confer protection against influenza virus infection. Although annual seasonal influenza vaccines provide some protection against currently circulating influenza strains, they lack efficacy against viruses expressing divergent globular head domains of HA. Moreover, antigenic drift within the globular head of circulating viruses necessitates frequent reformulation of the seasonal vaccine, a process that is both expensive and time-consuming. In this regard, vaccine strategies that generate antibodies with reactivity against an array of influenza viral strains could reduce the need for yearly influenza vaccination and increase our preparedness for potential pandemics. In this review, recent progress toward the generation of an influenza vaccine capable of eliciting hemagglutinin specific and broadly protective antibody responses is summarized. © 2014 Elsevier Ltd.


Cubas R.,Vaccine and Gene Therapy Institute of Florida | Perreau M.,University of Lausanne
Current Opinion in HIV and AIDS | Year: 2014

PURPOSE OF REVIEW: T follicular helper (Tfh) cells play a critical role as providers of B-cell help and dysfunction in Tfh/B-cell interactions can lead to autoimmunity or immunodeficiency. These observations have generated a great deal of interest in understanding how these cells are affected during HIV infection and how their functional changes might affect antibody responses. RECENT FINDINGS: Recent studies have shown that HIV/simian immunodeficiency virus (SIV) infection affects both Tfh-cell frequency and function and suggest that Tfh-cell perturbations might contribute to the relative inefficiency of HIV-infected individuals to generate broadly neutralizing antibodies (bNAbs). SUMMARY: The present review will highlight these recent findings addressing the role of Tfh cells in HIV infection as well as the impact HIV infection has on Tfh and circulating memory Tfh (cTfh) cell frequency and function. © 2014 Wolters Kulwer Health.


Sze A.,McGill University | Belgnaoui S.M.,McGill University | Olagnier D.,Vaccine and Gene Therapy Institute of Florida | Lin R.,McGill University | And 3 more authors.
Cell Host and Microbe | Year: 2013

Human T cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T cell leukemia and HTLV-1-associated myelopathies. In addition to T cells, HTLV-1 infects cells of the myeloid lineage, which play critical roles in the host innate response to viral infection. Investigating the monocyte depletion observed during HTLV-1 infection, we discovered that primary human monocytes infected with HTLV-1 undergo abortive infection accompanied by apoptosis dependent on SAMHD1, a host restriction factor that hydrolyzes endogenous dNTPs to below the levels required for productive reverse transcription. Reverse transcription intermediates (RTI) produced in the presence of SAMHD1 induced IRF3-mediated antiviral and apoptotic responses. Viral RTIs complexed with the DNA sensor STING to trigger formation of an IRF3-Bax complex leading to apoptosis. This study provides a mechanistic explanation for abortive HTLV-1 infection of monocytes and reports a link between SAMHD1 restriction, HTLV-1 RTI sensing by STING, and initiation of IRF3-Bax driven apoptosis. © 2013 Elsevier Inc.


Noto A.,Vaccine and Gene Therapy Institute of Florida
Journal of visualized experiments : JoVE | Year: 2013

Cytolytic activity of CD8+ T cells is rarely evaluated. We describe here a new cell-based assay to measure the capacity of antigen-specific CD8+ T cells to kill CD4+ T cells loaded with their cognate peptide. Target CD4+ T cells are divided into two populations, labeled with two different concentrations of CFSE. One population is pulsed with the peptide of interest (CFSE-low) while the other remains un-pulsed (CFSE-high). Pulsed and un-pulsed CD4+ T cells are mixed at an equal ratio and incubated with an increasing number of purified CD8+ T cells. The specific killing of autologous target CD4+ T cells is analyzed by flow cytometry after coculture with CD8+ T cells containing the antigen-specific effector CD8+ T cells detected by peptide/MHCI tetramer staining. The specific lysis of target CD4+ T cells measured at different effector versus target ratios, allows for the calculation of lytic units, LU30/10(6) cells. This simple and straightforward assay allows for the accurate measurement of the intrinsic capacity of CD8+ T cells to kill target CD4+ T cells.


van Montfoort N.,Vaccine and Gene Therapy Institute of Florida | Olagnier D.,Vaccine and Gene Therapy Institute of Florida | Hiscott J.,Vaccine and Gene Therapy Institute of Florida
Cytokine and Growth Factor Reviews | Year: 2014

Retroviruses can selectively trigger an array of innate immune responses through various PRR. The identification and the characterization of the molecular basis of retroviral DNA sensing by the DNA sensors IFI16 and cGAS has been one of the most exciting developments in viral immunology in recent years. DNA sensing by these cytosolic sensors not only leads to the initiation of the type I interferon (IFN) antiviral response and the induction of the inflammatory response, but also triggers cell death mechanisms including pyroptosis and apoptosis in retrovirus-infected cells, thereby providing important insights into the pathophysiology of chronic retroviral infection. Host restriction factors such as SAMHD1 and Trex1 play important roles in regulating innate immune sensing, and have led to the idea that innate immune defense and host restriction actually converge at different levels to determine the outcome of retroviral infection. In this review, we discuss the sensing of retroviruses by cytosolic DNA sensors, the relevance of host factors during retroviral infection, and the interplay between host factors and the innate antiviral response in different cell types, within the context of two human pathogenic retroviruses - human immunodeficiency virus (HIV-1) and human T cell-leukemia virus type I (HTLV-1). © 2014 Elsevier Ltd.


Belgnaoui S.M.,Jewish General Hospital | Belgnaoui S.M.,McGill University | Paz S.,Jewish General Hospital | Paz S.,McGill University | And 2 more authors.
Current Opinion in Immunology | Year: 2011

Sensing of RNA virus infection by the RIG-I-like receptors (RLRs) engages a complex signaling cascade that utilizes the mitochondrial antiviral signaling (MAVS) adapter protein to orchestrate the innate host response to pathogen, ultimately leading to the induction of antiviral and inflammatory responses mediated by type I interferon (IFN) and NF-κB pathways. MAVS is localized to the outer mitochondrial membrane, and has been associated with peroxisomes, the endoplasmic reticulum and autophagosomes, where it coordinates signaling events downstream of RLRs. MAVS not only plays a pivotal role in the induction of antiviral and inflammatory pathways but is also involved in the coordination of apoptotic and metabolic functions. This review summarizes recent findings related to the MAVS adapter and its essential role in the innate immune response to RNA viruses. © 2011 Elsevier Ltd.

Loading Vaccine and Gene Therapy Institute of Florida collaborators
Loading Vaccine and Gene Therapy Institute of Florida collaborators