The CyaA vector is an antigen delivery technology developed by Institut Pasteur. Genticel has an exclusive license on this technology since 2002.

In investigating the biology of whooping cough, Institut Pasteur studied and modified a protein - Bordetella pertussis adenylate cyclase (CyaA) and demonstrated that it was possible, by genetic engineering, to insert an antigen in the CyaA protein to activate the immune system against cells marked by that antigen (eg., cells infected by the HPV virus). The resulting recombinant protein is ideally suited to the development of immunotherapies.

Vaccines that are built with the CyaA vector are chimeric recombinant proteins consisting of the CyaA protein and the antigen of choice inserted by genetic engineering.

When injected into humans, the CyaA vector naturally delivers the inserted antigen directly to the immune system inducing cytotoxic (killer) CD8+ T cells and CD4+ (helper) T cells specific to these antigens. These killer cells then circulate around the body and destroy only the cells carrying the antigen inserted into the CyaA. This technology thus works by selectively targeting and eradicating the infected cells carrying the same antigen as the one inserted into the CyaA.


  1. CyaA specifically carries and delivers the antigen inserted in its sequence, to and into human immune sentinel cells
  2. The sentinel cells process the antigen and activate antigen-specific immune killer (cytotoxic) T cells and helper T cells
  3. The immune killer cells target and eliminate infected cells that contain the antigen, resulting in a therapeutic effect.

With these unique features, the CyaA platform and our improved proprietary platform, Vaxiclase, have the potential to treat a broad range of infectious diseases and cancers.
Genticel's lead investigational vaccine, GTL001 (ProCervix) was developed using the CyaA vector.

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