Design of a Novel Integration-deficient Lentivector Technology That Incorporates Genetic and Posttranslational Elements to Target Human Dendritic Cells

Abstract

As sentinels of the immune system, dendritic cells (DCs) play an essential role in regulating cellular immune responses. One of the main challenges of developing DC-targeted therapies includes the delivery of antigen to DCs in order to promote the activation of antigen-specific effector CD8 T cells. With the goal of creating antigen-directed immunotherapeutics that can be safely administered directly to patients, Immune Design has developed a platform of novel integration-deficient lentiviral vectors that target and deliver antigen-encoding nucleic acids to human DCs. This platform, termed ID-VP02, utilizes a novel genetic variant of a Sindbis virus envelope glycoprotein with posttranslational carbohydrate modifications in combination with Vpx, a SIVmac viral accessory protein, to achieve efficient targeting and transduction of human DCs. In addition, ID-VP02 incorporates safety features in its design that include two redundant mechanisms to render ID-VP02 integration-deficient. Here, we describe the characteristics that allow ID-VP02 to specifically transduce human DCs, and the advances that ID-VP02 brings to conventional third-generation lentiviral vector design as well as demonstrate upstream production yields that will enable manufacturing feasibility studies to be conducted.

Retrovirus-based vectors for transient and permanent cell modification

“…Combination of attachment site with IN mutations did not reduce residual integration events below the frequencies observed with IN inactivation alone [48]. However, a successful strategy was deletion of the polypurine tract (PPT) in LVV in addition to IN mutation [69,70], indicating that, in principle, there is room for improvement. Following RET, non-integrated vectors are present as both linear and circular forms.…”

Cellular Innate Immunity and Restriction of Viral Infection: Implications for Lentiviral Gene Therapy in Human Hematopoietic Cells

“…proposed by many to be exploited in the context of gene transfer applications [97][98][99]. Target cells can either be pre-exposed to virus-like particles that contain Vpx (Vpx-VLPs) [100] or Vpx can be directly incorporated into the LV during vector production through the use of a modified packaging plasmid engineered to contain an SIV-derived Vpx-interacting sequence [97,101].…”

Surface engineering of lentiviral vectors for gene transfer into gene therapy target cells

“…Odegard et al developed an integration-deficient LV that was designed to deliver antigen-encoding nucleic acids selectively to hDCs in vivo [43]. This LV utilizes a modified Sindbis virus gp to target hDCs through the Ctype lectin, DC-SIGN [23 ] and binds the homologue murine receptor SIGNR1. Preclinicals studies in mice showed that this vector exerted antitumor cytotoxic activity in both prophylactic and therapeutic settings.…”

“…For example, use of mannosidase inhibitors can alter the tropism of Sindbis virus gp-pseudotyped particles by increasing envelope binding to C-lectins such as DC-SIGN [21,22,23 ].…”