== Glycosylation modification of E1001 increases the ability of ID-VP02 to effectively utilize DC-SIGN as a receptor for binding and entry.(a) HT1080 cells stably expressing human DC-SIGN (HT1080 huDC-SIGN) were transduced with E1001 pseudotyped vectors encoding GFP that were produced either with kifunensine, swainsonine, or DMNJ in the culture media or in Rabbit Polyclonal to OR2AT4 the absence of additive. immune system to prevent or treat human diseases. Nowhere is usually this more apparent than in the field of cancer immunotherapy where the best challenge has been to induce anticancer immunity through activation of antigen-specific effector T cells (reviewed in ref.1). As sentinels of the immune system, dendritic cells (DCs) play an essential role in regulating cellular immune responses through antigen capture and presentation.2It would therefore be desirable to capitalize on the specific capability of DCs to drive cellular responses toward an antigen of choice when developing a platform for antigen-directed active immunotherapeutics. Delivering a cargo antigen to DCs in order to elicit an immune response has been exhibited through bothex vivo3andin vivoroutes.4However, currentex vivomethods have multiple limitations which can include the complexities of manufacturing and treatment, the risk of treatment-associated infections, and the overall cost of goods, while currentin vivodelivery systems may have consequences associated with inefficient DC tropism and subsequent antigen presentation by DCs as well as undesirable off-target effects. In order to minimize these limitations, Immune Design is usually developing a novel class of integration-deficient lentiviral vectors that have been engineered to deliver antigen-encoding nucleic PR-104 acids to human DCsin vivo. This specificity in targeting is achieved by using a modified version of a Sindbis virus envelope that naturally exhibits tropism toward human PR-104 DCs via the DC-specific ICAM-3 grabbing nonintegrin (DC-SIGN) receptor.5The ability to target DCs and elicit antigen-specific immune responses has been demonstrated with a prototype of this platform.6This prototype vector, like other third-generation lentiviral vectors, was generated using a split genome encoding the HIV-1 genesgag/polandrev,7and contains a self-inactivating deletion in the U3 region of the 3LTR (U3).8Unlike traditional LVs that use the pan-tropic VSV-G envelope glycoprotein, this prototype utilizes a mutated Sindbis virus envelope (SVGmu) to target DCs via DC-SIGN with reduced binding to heparan sulfate.6 However, this prototype vector has several limitations, which include the inability of integration-deficient versions to be produced at high enough yields that would render upstream production feasible for commercial applications. Immune Design has significantly advanced this prototype vector system by the addition of several design elements to generate our novel ID-VP02 platform. These elements include two impartial features that are engineered to eliminate integrase-dependent integration events, a novel envelope glycoprotein, termed E1001, that increases vector production yields and via posttranslational modification increases the ability of the vector to utilize human DC-SIGN as a receptor, and the inclusion of the accessory protein, Vpx from SIVmac, to increase the transduction efficiency of human DCs. In this report, we describe the specific elements that have been introduced into the design of ID-VP02 and we demonstrate that this novel integration-deficient lentiviral vector platform, which has been designed to deliver a cargo antigen to PR-104 human DCs, can target and transduce human DCs in preclinical settings. == Results == == Integration deficiency is usually rendered by two impartial design PR-104 elements == For clinical applications that require the direct administration of viral vectors but do not require sustained expression of the vector-delivered gene, such as for vaccines and antigen-directed immunotherapies, integration-defecient lentiviral vectors represent an appropriate and viable alternative to fully integration-competent lentiviral vectors for delivery of their genetic.