Replication-competent adenoviral vectors
Inventors
Peng, Bo • Voltan, Rebecca • Ensoli, Barbara • Robert-Guroff, Marjorie
Assignees
Istituto Superiore di Sanita ISS • US Department of Health and Human Services
Publication Number
US-9216214-B2
Publication Date
2015-12-22
Expiration Date
2025-11-17
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Abstract
This invention provides improved replication-competent adenoviral vectors. The improved vectors have both a hybrid regulatory unit that provides for high level transgene expression. The vectors can be use, e.g., for therapeutic or prophylactic purposes.
Core Innovation
This invention provides improved replication-competent adenoviral vectors comprising a hybrid regulatory unit that includes a human cytomegalovirus (CMV) immediate early promoter and an adenovirus tripartite leader sequence. These vectors allow high level expression of a transgene, overcoming limitations seen with previous vectors, particularly replication-defective adenoviruses.
The background highlights that prior art conflicted regarding the need for a heterologous promoter for replication-competent adenovirus vectors and demonstrated that some transgenes such as hepatitis B virus surface antigen were poorly expressed when not properly controlled. There was no prior suggestion that a hybrid regulatory unit combining the CMV promoter and adenovirus tripartite leader would enhance transgene expression in replication-competent adenoviruses.
The invention solves this problem by incorporating the hybrid regulatory unit in the vectors, resulting in greatly enhanced gene expression in replication-competent adenovirus vectors. This enables high level transgene expression relative to earlier vectors, allowing use of lower viral doses and reducing immunopathology while enhancing immune responses in vivo.
Claims Coverage
The patent contains one independent claim outlining a method of inducing immune response using a novel adenovirus vector. The main inventive features relate to the adenovirus vector structure, replication competence, hybrid expression cassette components, and the use of HIV genes as transgenes.
Replication-competent adenovirus vector comprising hybrid expression cassette
The adenovirus vector is replication-competent and comprises an endogenous adenovirus tripartite leader sequence and a hybrid expression cassette that includes a CMV immediate early promoter, a second adenovirus tripartite leader sequence, and a transgene.
Use of multiple adenovirus types as vector backbone
The adenovirus vector can be selected from adenovirus types 2, 4, 5, and 7, providing flexibility in vector design.
Deletion of functional E3 region and transgene insertion
The adenovirus vector lacks a functional E3 region, which can be deleted, and allows for the insertion of the hybrid expression cassette into the deleted E3 region.
HIV gene transgene encoding regulatory or structural proteins
The transgene encoded by the vector can be an HIV gene, including HIV regulatory genes encoding Nef or Tat, with the Nef optionally being non-myristoylated and Tat optionally lacking transactivation function, as well as HIV structural genes encoding Gag or Env.
Use of spliced and specific tripartite leader sequences
The second adenovirus tripartite leader sequence in the hybrid expression cassette is a spliced sequence, which can be specifically the sequences disclosed as SEQ ID NO: 1 or SEQ ID NO: 2.
The independent claim covers the method of inducing an immune response by administering replication-competent adenovirus vectors with a hybrid expression cassette comprising CMV promoter and tripartite leader sequences, lacking functional E3, encompassing various adenovirus serotypes, and including HIV gene transgenes, highlighting advantages of enhanced transgene expression and immunogenicity.
Stated Advantages
The vectors provide high levels of gene expression relative to previous vectors, allowing the use of lower adenovirus doses in vivo.
Replication competence leads to a greater number of DNA templates during vector replication, amplifying transgene expression.
In vivo replication stimulates pro-inflammatory cytokine production, augmenting the immune response.
The hybrid regulatory unit composed of CMV promoter and tripartite leader sequence significantly increases transgene mRNA and enhances translation efficiency.
Vectors can induce strong cellular immune responses to HIV antigens such as Tat and Nef, as well as enhance immune responses to co-administered antigens.
Documented Applications
Use of improved replication-competent adenovirus vectors for therapeutic or prophylactic vaccination, including eliciting immune responses against HIV genes such as tat and nef.
Vaccination strategies in animals (mice, rhesus and cynomolgus monkeys, chimpanzees) to induce cellular and humoral immunity against HIV antigens.
Ex vivo gene transfer or in vivo gene transfer to achieve high level expression of genes of interest using the adenovirus vectors.
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