Induction of HIV‐specific T and B cell responses with a replicating and conditionally infectious lentiviral vaccine

Abstract

The development of an HIV vaccine that induces broad and potent immunity is critically needed. Viruses, including lentiviruses, have been used as vectors for ex vivo transduction of antigens into dendritic cells (DC). We hypothesized that DC transduced with a vector that allows selective infection of DC could induce potent immunity by continually priming DC. A lentiviral vector encoding HIV gag-pol without env would form viral cores in transduced DC, but would release non-infectious particles by budding into endosomes and releasing apoptotic bodies or exosomes containing viral cores. DC function by endocytosing DCderived apoptotic bodies, and they are specialized in their ability to move endocytic contents into the cytoplasm. We postulated that endocytosis of vector cores could lead to transduction of a second round of DC. In this report, we demonstrate accumulation of viral cores inside transduced DC and show second-round transduction of immature DC that endocytose transduced DC in vitro. The effectiveness of immunization of mice with transduced DC to induce specific lymphocyte activation was assessed. Mice developed antigen-specific T cell responses and specific antibodies after immunization. Transduction of DC with a replication-competent but conditionally infectious lentivirus could be a novel vaccine strategy for HIV.Key words: Dendritic cell Á HIV Á Immune response Á Lentiviral vector Introduction A safe and effective vaccine for HIV is critically needed to combat the worldwide scourge of AIDS. While the correlates of immune protection have yet to be clearly defined, either for protective or therapeutic vaccines, it is widely believed that both CD4 + and CD8 + T cell as well as humoral immunity are important. How sufficiently broad, potent, and sustained responses can be elicited has yet to be determined, and this represents a critical gap in our understanding of how to generate an effective vaccine such that protective or therapeutic immunity can be achieved. Selection and activation of lymphocytes is a function of antigen presentation by dendritic cells (DC), making DC a logical vehicle for immunotherapy [1]. Early studies showed that DC loaded with tumor extracts [2,3] or antigenic peptides [2][3][4][5] induced anti-tumor immunity in both laboratory mice [2,4,5] and human melanoma patients [3]. More recently, viruses have been used as gene transfer vectors for the ex vivo transduction of DC with selected antigens. Lentiviral vectors have a number of advantages over adenoviruses, adeno-associated viruses, poxviruses, and alphaviruses. Transduction is stable due to chromosomal integration and non-dividing cells are efficiently transduced [6]. Lentivirally transduced DC have been studied for their ability to induce anti-tumor immunity. Breckpot et al. [7] demonstrated that murine DC transduced with a lentivirus encoding a truncated variant of ovalbumin (OVA) protected against tumor challenge with OVA-expressing cells. He et al. [8] recently described the transduction of murine DC with a lentiviral vector...

In VivoElectroporation of Minicircle DNA as a Novel Method of Vaccine Delivery To Enhance HIV-1-Specific Immune Responses

“…DNA vaccines are third-generation vaccines and have evolved significantly over the last 20 years (2,3). Compared to first-generation vaccines (whole-organism vaccines) and second-generation vaccines (subunit vaccines), DNA vaccines have more safety, flexibility, and stability and can readily elicit both humoral and broad cellular responses (4)(5)(6). The first human trial of a DNA-based vaccine is for the treatment of human HIV infection, and it was initiated almost 20 years ago (7).…”

Enhancing immunogenicity and cross-reactivity of HIV-1 antigens byin vivotargeting to dendritic cells

“…Mannose receptor [98,99] Dec-205 [100][101][102] LOX-1 [103,104] Langerin [105] DC-SIGN [107][108][109][110][111] Clec9A [112,113] CD40 [117][118][119] FcR family [120][121][122][123][124][125][126][127][128][129][130][131][132] future science group Review Cruz, Rueda, Tacken, Albericio, Torensma & Figdor vaccination [79]. However, exosomes produced by T cells and DCs from HIV-1-infected patients have been associated with HIV-1 dissemination, although a budding pathway is not shared by exosomes and HIV-1 [80].…”

Controllable inhibition of hepatitis B virus replication by a DR1-targeting short hairpin RNA (shRNA) expressed from a DOX-inducible lentiviral vector

“…One potential strategy is RNA interference (RNAi), a gene silencing regulatory mechanism present virtually in all eukaryotes, which employs double-stranded RNA molecules to degrade, or functionally inactivate, target RNAs in a sequence-specific manner [3][4][5]. Numerous studies have shown that replication of various viruses including HIV-1 [6][7][8], HCV [9][10][11], HSV-1 [12], SARSassociated coronavirus [13] as well as HBV [14][15][16][17], can be suppressed by RNAi, using synthetic siRNAs and plasmid-based shRNAs. However, due to their short halflife and low transfection efficiency, clinical application is limited.…”