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Open Access Publications from the University of California

Scholarly Works (4 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2018)

The innate and adaptive immune responses are intertwined systems that require complex regulation to achieve an efficient protection from pathogens and diseases. Upon sensing of a foreign attack through specialized receptors, cells activate the transcription of cytokines such as type-I interferons to emit a danger signal and regulate their function. The strength and complexity of this signal is dependent on the type of pathogen recognition receptor (PRR) engaged. These signals can then skew the type of antigen-specific adaptive immune response that is created. In the past decade, there has been a renewed interest in using the immune system to fight cancer. A better understanding of how one can use the innate immune signals to trigger an efficacious adaptive immune response would help improve novel immunotherapies.

One of the tools used to trigger such immune response is oncolytic viruses, such as Herpes Simplex virus type 1 (HSV-1). HSV-1 has evolved proteins able to regulate the type-I interferon response to enhance its ability to reproduce and limit attacks from the immune system. In this work, we examine the entire HSV-1 genome to determine which genes are responsible for this phenotype and characterize a novel interferon regulating protein, UL42.

Another promising pathogen that has been used to provoke anti-tumoral responses is the bacterium Listeria monocytogenes (Lm). Lm infection leads to a strong CD8 cytotoxic T-cell response which can be retargeted towards cancerous antigens. Here, we describe how we developed a construct to express neoantigens in Lm to trigger an antigen-specific immune response. Our results indicate that this strategy was successful in vitro but did not translate in vivo, possibly because of poor expression of the construct.

The antigen-specific T-cell receptor (TCR) repertoire can vary in diversity (breath) and individual clonal characteristics such as avidity or differentiated cell type. The extent to which the innate immune response regulates the selection of the TCR repertoire in response to a specific pathogen is poorly understood. Herein, we use an in vivo mouse model to investigate how different PRR ligands can affect the selection of this repertoire. Our results suggest that ligands for distinct toll-like receptors (TLR) might contribute to the selection of different TCR variable fragment families. We did not detect any difference in the complexity of the repertoire following stimulation with different TLR ligands but suggest this might be due to technical limitations associated with our in vivo model.

    Cover page: Optimizing innate immune signals to enhance antigen-specific adaptive responses
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2019)
    In spite of several decades of research focused on understanding the biology of human herpes simplex virus 1 (HSV-1), no tool has been developed to study its genome in a high-throughput fashion. Here, we describe the creation of a transposon insertion mutant library of the HSV-1 genome. Using this tool, we aimed to identify novel viral regulators of type I interferon (IFN-I). HSV-1 evades the host immune system by encoding viral proteins that inhibit the type I interferon response. Applying differential selective pressure, we identified the three strongest viral IFN-I regulators in HSV-1. We report that the viral polymerase processivity factor UL42 interacts with the host transcription factor IFN regulatory factor 3 (IRF-3), inhibiting its phosphorylation and downstream beta interferon (IFN-β) gene transcription. This study represents a proof of concept for the use of high-throughput screening of the HSV-1 genome in investigating viral biology and offers new targets both for antiviral therapy and for oncolytic vector design.IMPORTANCE This work is the first to report the use of a high-throughput mutagenesis method to study the genome of HSV-1. We report three novel viral proteins potentially involved in regulating the host type I interferon response. We describe a novel mechanism by which the viral protein UL42 is able to suppress the production of beta interferon. The tool we introduce in this study can be used to study the HSV-1 genome in great detail to better understand viral gene functions.
      Cover page: Comprehensive Mutagenesis of Herpes Simplex Virus 1 Genome Identifies UL42 as an Inhibitor of Type I Interferon Induction.
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2018)
      Detection of viral genomes by the innate immune system elicits an antiviral gene program mediated by type I interferons (IFNs). While viral RNA and DNA species induce IFN via separate pathways, the mechanisms by which these pathways are differentially modulated are unknown. Here we show that the positive regulator of IFN in the RNA pathway, TRAF3, has an inhibitory function in the DNA pathway. Loss of TRAF3 coincides with increased expression of the alternative NF-κB-inducing molecule, NIK, which interacts with the DNA pathway adaptor, STING, to enhance IFN induction. Cells lacking NIK display defective IFN activation in the DNA pathway due to impaired STING signaling, and NIK-deficient mice are more susceptible to DNA virus infection. Mechanistically, NIK operates independently from alternative NF-κB signaling components and instead requires autophosphorylation and oligomerization to activate STING. Thus a previously undescribed pathway for NIK exists in activating IFN in the DNA pathway.
        Cover page: A TRAF3-NIK module differentially regulates DNA vs RNA pathways in innate immune signaling
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2017)
        New influenza vaccines that provide effective and broad protection are desperately needed. Live attenuated viruses are attractive vaccine candidates because they can elicit both humoral and cellular immune responses. However, recent formulations of live attenuated influenza vaccines (LAIVs) have not been protective. We combined high-coverage transposon mutagenesis of influenza virus with a rapid high-throughput screening for attenuation to generate W7-791, a live attenuated mutant virus strain. W7-791 produced only a transient asymptomatic infection in adult and neonatal mice even at doses 100-fold higher than the LD50 of the parent strain. A single administration of W7-791 conferred full protection to mice against lethal challenge with H1N1, H3N2, and H5N1 strains, and improved viral clearance in ferrets. Adoptive transfer of T cells from W7-791-immunized mice conferred heterologous protection, indicating a role for T cell-mediated immunity. These studies present an LAIV development strategy to rapidly generate and screen entire libraries of viral clones.
          Cover page: Generation of a Live Attenuated Influenza Vaccine that Elicits Broad Protection in Mice and Ferrets
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