Genome editing provides solution for cell therapy safety and immune tolerance: a guide for a One4All pluripotent cell line (#10)

Andras Nagy

Pluripotent stem cells have accelerated the development of new avenues for targeting degenerative diseases and cancer with cell-based therapies.  Numerous human therapies are currently on their way to treat devastating conditions. However, concerns about the cell-safety hold back the full utilisation of these promising new treatments. Here we introduce a concept and show the associated genome engineering strategy that addresses this issue and provides a solution for “fail-safe” cell therapies.

To ensure the reliable expression of a suicide transgene system in proliferating cells, we transcriptionally linked it to a cell division essential endogenous locus (CDEL) in a homozygous manner. Our prototype suicide gene was the herpes simplex virus-thymidine kinase (HSV-TK), and the prototype CDEL was CDK1. The coding regions of these two kinases were connected with a viral 2A sequence. Using mouse and human embryonic stem cell lines with the above homozygous modification, we showed an extremely efficient and reliable ablation of proliferating cells both in vitro and in vivo by ganciclovir treatment, the pro-drug for HSV-TK.

Using published and our experimental measures of forward mutation rates, we defined mathematically the level of safety of therapeutic batches of these cells. Our general approach to assess and quantify the safety will be critical to make informed decisions by the regulators, doctors, and patients to advance the modern medicine-transforming cell therapies.

Building on the fail-safe technology, we addressed the next hurdle faced by cell therapies; a solution for induced allograft tolerance. We showed that the expression of eight local-acting, immunomodulatory transgenes introduced into embryonic stem cells is sufficient to protect cell derivatives against rejection in allogenic, immune-competent recipients.  Allografts survive long-term, in different MHC-mismatched recipients, and without immunosuppressive drugs. Most importantly, the recipients of these engineered cells do not have suppressed systemic immune function.

The combination of the fail-safe and immune tolerance genome editing makes the One4All cell line and therapeutic cell development a reality.


Can advanced immunotherapy make it possible?

If money wasn’t a problem – what would we do and how would we do it?

The conference is being held in Melbourne Australia from March 15th to March 18th, 2018.

Key leaders from around the world will address these questions with a focus on the following:

  • CAR-T cells
  • CAR – non-T Cells
  • Checkpoint blockade inhibitors
  • Viral transduction for clinical applications
  • Gene Editing – CRISPR, Sleeping Beauty, PiggyBac, Talens, ZFNs
  • Neo antigen discovery
  • TCR’s targeting cancer
  • Dendritic cells /vaccines
  • Cytokine induced killer cells
  • Antibody-based therapies
  • Immune reconstitution
  • “off the shelf” allogeneic anti cancer T cells
    • Generation of anti-cancer T cells from stem cells, iPSC
    • Gene edited donor cells
    • Manufacturing immune cells for clinical use: in vitro scale up for in vivo expansion
    • Industry perspective of developing immune therapies
    • Regulatory requirements
    • Public Forum: patient Advocacy; philanthropy

For further details on this provocative conference: