Adoptive Cell Therapy Inspired On Neo-antigens (ACTION)

Tumor cells accumulate genetic changes, some giving rise to expression of neoantigens that are considered foreign
by the immune system. When presented in human leukocyte antigen (HLA) proteins, neoantigens can be bound by
high avidity T-cell receptors (TCRs) of cognate T cells, enabling selective tumor cell elimination. Hence, neoantigens
are used to develop personalized cancer immunotherapies. The overall project aim is to deliver a proof-ofconcept (PoC) on neoantigen-targeting adoptive cell therapy (ACT). Identification of neoantigens for cancer
immunotherapy relies on whole exome and RNA sequencing followed by prediction of their affinity for HLA proteins,
presentation, and immunogenicity, using computational algorithms. Existing prediction algorithms do not take all
aspects of antigen processing and presentation into account and thus require validation. The 1st aim was to
develop an mRNA platform for neoantigen validation. We proposed to develop a synthetic DNA template (SDT)
to efficiently produce single neoantigen (SNA) mRNA. We further proposed to produce mRNA encoding the most
common HLA proteins in the Caucasian population. These platforms would allow validation of neoantigen
presentation by tandem mass spectrometry (LC-MS/MS) following the transfection of neoantigen and HLA mRNA
into antigen presenting cells. The 2nd aim was to develop an mRNA platform to identify TCRs specific for
neoantigens followed by the use of TCR mRNA to develop an adoptive T-cell therapy. We proposed to develop
a long SDT (LSDT) to efficiently produce TCR mRNA. This platform together with the SNA mRNA would allow
verification of neoantigen-specific TCRs, a key aspect before producing cell therapies for adoptive T-cell transfer.
This mRNA could further be used to transfect T cells for adoptive T-cell therapy and study their tumor cell killing
potential. Overall, this project takes steps to validate neoantigen prediction algorithms, allowing to improve them for
more truthful detection of personalized cancer targets, and to develop neoantigen-targeting adoptive T-cell
therapies.