Synthetic peptide versions of 48 non-mutated ovarian cancer antigens successfully triggered immune cell expansion, suggesting they could serve as targets for cancer immunotherapy.
48 antigens testedNon-mutated ovarian cancer peptide antigens were shown to expand CD8 killer T cells, confirming their potential as immunotherapy targets
What the researchers found
Of 91 previously identified tumor-specific antigens from ovarian cancer, 48 were selected for immunogenicity testing. When dendritic cells were pulsed with synthetic peptide versions of these antigens, they presented them at high levels on their surface. These peptide-loaded dendritic cells successfully expanded sizeable populations of CD8 T cells from healthy donors, confirming that the immune system can recognize and respond to these non-mutated cancer antigens.
The abundance of antigen presentation correlated with predicted HLA binding affinity, suggesting that computational tools can help predict which antigens will be most immunogenic.
Why it matters
Ovarian cancer has barely benefited from the immunotherapy revolution because suitable antigen targets have been hard to find. This study shows that non-mutated, epigenetically driven tumor antigens — presented as peptides — can effectively trigger immune responses, potentially opening the door to peptide-based vaccines or adoptive cell therapies for a cancer with few good treatment options.
The numbers in context
91 tumor-specific antigens identified · 48 TSAs tested for immunogenicity · CD8 T cell expansion confirmed · Antigens from non-exonic genomic regions
How the study worked
Researchers used proteogenomic analysis to identify tumor-specific antigens from primary epithelial ovarian cancer tumors. They synthesized 48 selected TSA peptides, pulsed them onto dendritic cells, and used targeted mass spectrometry to confirm presentation. Immunogenicity was tested by stimulating naïve CD8 T cells from healthy blood donors with TSA-pulsed dendritic cells, measuring expansion via MHC-peptide tetramer staining and TCR Vβ CDR3 sequencing.
Who was studied
Healthy blood donors (for T cell isolation); primary epithelial ovarian cancer tumor samples
What this study cannot tell us
The study tested T cell responses from healthy donors, not ovarian cancer patients whose immune systems may be suppressed by the tumor microenvironment. All work was done in laboratory conditions (in vitro), so it remains unknown whether these antigens would trigger effective immune responses in patients. The fraction of EOC tumors expressing each antigen was not fully characterized.
How to read the evidence
This is a laboratory-based (in vitro) experimental study using primary tumor samples and healthy donor immune cells. It provides proof-of-concept for antigen immunogenicity but has not been tested in patients.
When this study was published
Published in 2024, this is very recent research at the forefront of cancer immunotherapy development. Clinical translation of these findings is likely still in early stages.
The bigger picture
Most successful cancer immunotherapies target mutated proteins (neoantigens), but many cancers — including ovarian cancer — have relatively few mutations. This study shows that epigenetically driven, non-mutated antigens can also trigger strong immune responses when delivered as peptides, potentially expanding immunotherapy to cancers that were previously considered poor candidates.
Questions still open
- Will these peptide antigens trigger effective immune responses in ovarian cancer patients, not just healthy donors?
- Can peptide vaccines based on these antigens overcome the immunosuppressive tumor microenvironment in ovarian cancer?
- Could this epigenetic antigen approach be applied to other cancers with low mutation rates?
Common questions
Why hasn't immunotherapy worked well for ovarian cancer?
What makes these antigens different from typical cancer targets?
Read the original research
Immunogenicity of Non-Mutated Ovarian Cancer-Specific Antigens.
Current oncology (Toronto, Ont.), 31(6), 3099-3121
Citation
Hesnard, Leslie; Thériault, Catherine; Cahuzac, Maxime; Durette, Chantal; Vincent, Krystel; Hardy, Marie-Pierre; Lanoix, Joël; Lavallée, Gabriel Ouellet; Humeau, Juliette; Thibault, Pierre; Perreault, Claude. (2024). Immunogenicity of Non-Mutated Ovarian Cancer-Specific Antigens.. Current oncology (Toronto, Ont.), 31(6), 3099-3121. https://doi.org/10.3390/curroncol31060236