Elimination of packaging sequences from retroviruses to produce improved vectors for gene delivery

Lead Research Organisation: University College London
Department Name: Institute of Child Health

Abstract

The ability to insert genes into cells can be used to study the roles of genes, produce useful proteins like antibodies and correct mutated cells in patients with genetic disorders. Viruses can act as gene delivery vehicles (or 'vectors') because they have evolved the ability to insert genes into cells. We use a modified HIV virus which is unable to reproduce or cause disease but can deliver genes to cells. This vector is used in laboratories across the world but has some drawbacks such as carrying about 18% of the HIV genome and being limited in terms of the size of gene it can deliver. We have already developed a streamlined HIV vector called LTR1 which carries only 3% of the HIV genome. We believe that LTR1 may be an improvement on the previous HIV vector in terms of safety and efficiency so would like to test them side by side. We will licence LTR1 commercially so that this technological breakthrough will be available to as many researchers and industrial partners as possible.

Publications

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Vink CA (2017) Eliminating HIV-1 Packaging Sequences from Lentiviral Vector Proviruses Enhances Safety and Expedites Gene Transfer for Gene Therapy. in Molecular therapy : the journal of the American Society of Gene Therapy

 
Description Interim report:
The objectives of this project are to secure intellectual property protection for our next-generation lentiviral vector (LTR1), to collect data demonstrating its capabilities as a DNA delivery system, to publicise these data as widely as possible, and to enter into two-way discussions with potential end users in academia, industry, and medicine to discuss their objectives and how licensing the LTR1 vector could improve upon their current approaches to gene delivery.
Interim results:
LTR1 is novel because for the first time we have managed to remove most of the remaining HIV-1 genome which remained in this vector. Although these viruses have been disabled and are safe to use, the presence of the remaining HIV DNA can cause problems in several different ways.
This project has developed from work started in a project funded by the BBSRC (grant BB/100212X/1) and many rounds of optimisation have had to be performed so that the HIV DNA can effectively be removed as part of the gene delivery process, without destroying the virus or its ability to deliver genes. We are now at the stage where the vector can be produced in sufficient amounts, and which works effectively at delivering genes in cell lines and in vivo.
We have shown that the HIV DNA is removed, as expected, during the delivery of the gene. One benefit of this is that it removes the 'packaging signal' so even when exposed to HIV proteins, viral particles cannot be made in remobilisation assays, showing that we have made the vector safer for single hit gene delivery. Sequencing of the vector has shown that the theory of removing the HIV region is correct and the vector behaves as we expect.
A patent has been filed for LTR1 and is now at the PCT stage. We have presented the technology at international conferences and directly targeted companies who use lentiviral vectors to gain more interest in LTR1 and encourage commercialisation of the product.

Update March 2016. The LTR-1 vector has continued to show comparable or improved efficacy and has been used to correct a model of genetic disease. The manuscript to describe this vector has been drafted.
Update 2019. After additional data generation, the LTR-1 project was published in Molecular Therapy, generating significant interest in the system from other laboratories, internationally.
Exploitation Route LTR1 is of interest to many in industry for commercial application, as well as academic colleagues who are interested in producing a potentially safer vector. Now that the PCT patent filing is in place, we are able to discuss the technology more freely with industrial partners and have started early-stage engagement with several interested parties. Material Transfer Agreements are also being put in place so we can share the vector with academic scientists to LTR1 can be tested in many different applications, which will help develop the system faster and create more interest and impact. LTR1 can be used in numerous applications, from gene therapy of inherited and acquired diseases, to gene delivery to help answer basic science questions. In the second half of the grant, we are performing experiments to fully characterise the system and this will be done in collaboration with colleagues internationally.
Update, March 2016
Several internationl groups now have access to LTR-1 and are continuing to test the new vector.
Sectors Education,Pharmaceuticals and Medical Biotechnology
URL http://www.ucl.ac.uk/ich/iiip/mci/gene-therapy-vector-dev
 
Description Interim report: The development of LTR1 is primarily as an improved vector for delivering genes for therapy of disease, but also as a tool for understanding the mechanisms of HIV infections and for investigating cell genetics and biology. So far, the impact of this has been: Societal Given the translational nature of LTR1, we have taken the opportunity to speak with members of the public to explain the rationale behind gene therapy and how we hope to improve treatments with the new vector. This has been carried out through public engagement days run with the British Society of Gene and Cell Therapy, as well as meeting with charities and funders to give tours of the laboratory and discuss our work. Academic The new vector is a significant development on standard lentiviral backbones, and so we have engaged with virologists, molecular biologists and other interested parties to discuss the project and how it can be applied and tested further in a range of circumstances. We have disseminated information about LTR1 at international conferences (American Society for Gene and Cell therapy, European Society for Gene and Cell Therapy, British Blood Transfusion Society) and developed a webpage and used social media to interact with as many people as possible. Because LTR1 is changing our understanding of how the HIV lifecycle progresses, we teach students about this vector, and gene therapy in general on our MSc in Cell and Gene Therapy and MRes in Biomedicine courses at UCL, as well as at MSc and BSc level at other universities (including Oxford, Kings College London, Royal Holloway University of London). Industrial / economic impact. One of the top objectives of the Follow on Fund is to commercialise the LTR1 product. We have therefore applied for protection on our Intellectual Property and are currently at the PCT stage of filing. During international travel to conferences, we have taken the opportunity to visit local companies that specialise in gene therapy or gene delivery and have interesting discussions with potential Industrial partners who are now in contact with our business managers at UCL-B. This process is ongoing and we intend to contact more industrial and academic partners as the project progresses. Update: 2019. In the past 3 years, both Dr Steven Howe and Dr John Counsell have presented results from experiments developing LTR-1 at the American Society of Cell and Gene Therapy, and other conferences, generating significant interest in the biology and application of these vectors. Although the Primary Investigator and postdoctoral research initially working on this project have now left UCL and are unable to continue the work, Dr John Counsell is continuing to seek funding to developing these vectors further. This has culminated in a recent publication in Molecular Therapy, continued discussions with UCL-Business for defending the Intellectual Property, and increased interest from potential collaborators. Dr Counsell is working with colleagues in UCL genomics to develop this work further.
Sector Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology
Impact Types Societal,Economic