DAI (DLM-1/ZBP1) as a Genetic Adjuvant for DNA Vaccines That Promotes Effective Antitumor CTL Immunity

Abstract

DNA vaccination is an attractive approach to induce antigen-specific cytotoxic CD8(+) T lymphocytes (CTLs), which can mediate protective antitumor immunity. The potency of DNA vaccines encoding weakly immunogenic tumor-associated antigens (TAAs) can be enhanced by codelivering gene-encoded adjuvants. Pattern recognition receptors (PRRs) that sense intracellular DNA could potentially be used to harness intrinsic immune-stimulating properties of plasmid DNA vaccines. Consequently, the cytosolic DNA sensor, DNA-dependent activator of interferon (IFN) regulatory factors (DAI), was used as a genetic adjuvant. In vivo electroporation (EP) of mice with a DAI-encoding plasmid (pDAI) promoted transcription of genes encoding type I IFNs, proinflammatory cytokines, and costimulatory molecules. Coimmunization with pDAI and antigen-encoding plasmids enhanced in vivo antigen-specific proliferation, and induction of effector and memory CTLs. Moreover, codelivery of pDAI effectively promoted CTL and CD4(+) Th1 responses to the TAA survivin. The DAI-enhanced CTL induction required nuclear factor κB (NF-κB) activation and type I IFN signaling, but did not involve the IFN regulatory factor 3 (IRF3). Codelivery of pDAI also increased CTL responses to the melanoma-associated antigen tyrosinase-related protein-2 (TRP2), enhanced tumor rejection and conferred long-term protection against B16 melanoma challenge. This study constitutes "proof-of-principle" validating the use of intracellular PRRs as genetic adjuvants to enhance DNA vaccine potency.

NF-κB activation during intradermal DNA vaccination is essential for eliciting tumor protective antigen-specific CTL responses

“…Despite the ability of NF-κB to support malignant cell survival, proliferation, and metastatic potential when expressed in tumor cells; 41 activation of NF-κB during antigen presentation has been extensively demonstrated to promote anti-tumor immune responses using TLR agonists 27,28 and DNA vaccine adjuvants. 24 In conclusion, in our study we demonstrate the essential nature of NF-κB in establishing CTL immunity after intradermal DNA vaccination. However, identifying which of the multiple DNA-sensing receptors that is involved in sensing intradermally electroporated DNA will be the focus of future studies.…”

“…23 Thus, this plasmid allows blocking of NF-κB activation specifically at the vaccination site in the context of DNA vaccines. 24 To test the activation of NF-κB during DNA vaccination, a NF-κB luciferase reporter plasmid was i.d EP into the hindquarters of mice as done with DNA vaccines. In vivo luciferase activity was detected six hours after intradermal electroporation, which is indicative of early NF-κB activation.…”

Mucosal co-immunization with AIM2 enhances protective SIgA response and increases prophylactic efficacy of chitosan-DNA vaccine against coxsackievirus B3-induced myocarditis

“…30,31 It has been demonstrated that DNA-dependent activator of IFNregulatory factors (DAI) overexpression in vivo can boost DNAsensing innate immune activation and generate a proinflammatory microenvironment, which is essential for effective CTL induction and long-lasting antitumor immunity. 32 Co-immunization with retinoic acid inducible-gene I (RIG-I) agonist enhances humoral immune response induced by influenza virus DNA vaccine. 33 Consistently, boosting innate immune PRR signaling by co-expressing intracellular adaptor molecules or downstream transcription factors as genetic adjuvants are efficient strategies for enhancing immunogenic of DNA vaccines.…”

Intracellular Systems for Detection of Exogenous Nucleic Acids and Triggering Mechanisms of Immune Response to Dna Internalization

“…Medical Immunology Медицинская Иммунология длиной не менее 45 п.о., не содержащая CpG-мотивов) и запуска DAI-опосредованного пути активации синтеза интерферонов/цитокинов [49,76,87]. Описано семейство рецепторов, содер-жащих HIN-200 домен (семейство HIN-200, или PYHIN), который непосредственно связы-вается с дцДНК, что приводит к олигомеризации сенсорной молекулы и активации трансдуциру-ющего пути [9,84], как это показано, например, для белка семейства HIN-200, IFI16.…”

“…В результате на ДК повышается экспрессия поверхностных молекул MHC I-и II-класса, костимуляторных молекул (CD40, CD80, CD86), хемокиновых рецепторов. Кроме того, ДК сами начинают активно секретировать хемо-кины и цитокины, необходимые для привлече-ния эффекторных клеток и индукции их диффе-ренцировки [7,44,49,76,80,87,96,97].…”