Routine detection of reactive Cyfra21-1-specific CD8+ T cells and its predictive value for responsiveness to
Shilong Song1, Yandan Wu2, Yu Zhao2
1Department of Radiation Oncology, The First Affiliated Hospital of Bengbu Medical University, Bengbu, Anhui, China.
Abstract:
Immune checkpoint inhibitors are widely used in non-small cell lung cancer (NSCLC), but with limited overall response rates. Indicators predicting immunotherapy response are hard to routinely detect due to their invasiveness. This study systematically screened for CD8+T-cell epitopes in Cytokeratin Fragment Antigen 21-1 (Cyfra21-1), a valuable NSCLC tumor marker, through a combination of in silico prediction, ex vivo co-cultures of peptides with patient-derived peripheral blood mononuclear cells (PBMCs), peptide competition binding assays, and peptide immunization in humanized mice. A total of 37 novel CD8+T-cell epitopes were confirmed to exhibit immunogenicity in a real-world lung cancer cohort comprising 150 patients. These epitopes were restricted by 13 HLA-A, 15 HLA-B, and 14 HLA-C prevalent allotypes which cover the majority of Northeast Asian population. Using these epitope peptides, a universal ELISpot assay was established to count reactive Cyfra21-1-specific CD8+T cells, and a cohort of 70 NSCLC patients scheduled to receive PD-1/PD-L1 inhibitor therapy was tested. The baseline count of reactive Cyfra21-1-specific CD8+T cells in PBMCs was identified as an independent predictor of patient responsiveness to immunotherapy, with an AUC of 0.757 and a cut-off value of 25.5 SFUs/4 × 10⁵ PBMCs that distinguished responders from non-responders. This study is the first to construct a broad-spectrum CD8+T-cell epitope library of the Cyfra21-1 antigen in Northeast Asians, establish a universal assay for measuring Cyfra21-1-specific CD8+T cell reactivity, and validate the predictive value of Cyfra21-1-specific CD8+T cells for immunotherapy response in NSCLC patients.
Insights
Researchers identified novel CD8+ T-cell epitopes in Cyfra21-1, a non-small cell lung cancer marker. A new assay using these epitopes predicts immunotherapy response in NSCLC patients.
Area of Science:
- Immunology
- Oncology
- Biochemistry
Background:
- Immune checkpoint inhibitors (ICIs) show limited response rates in non-small cell lung cancer (NSCLC).
- Predictive biomarkers for ICI response are often invasive and difficult to detect routinely.
- Cytokeratin Fragment Antigen 21-1 (Cyfra21-1) is a valuable NSCLC tumor marker.
Purpose of the Study:
- To systematically screen for CD8+ T-cell epitopes within the Cyfra21-1 antigen.
- To develop a universal assay for measuring Cyfra21-1-specific CD8+ T-cell reactivity.
- To validate the predictive value of Cyfra21-1-specific CD8+ T cells for immunotherapy response in NSCLC.
Main Methods:
- In silico prediction of CD8+ T-cell epitopes.
- Ex vivo co-cultures of peptides with patient-derived peripheral blood mononuclear cells (PBMCs).
- Peptide competition binding assays and immunization in humanized mice.
- Development of a universal ELISpot assay.
- Testing in a cohort of 70 NSCLC patients receiving PD-1/PD-L1 inhibitors.
Main Results:
- 37 novel immunogenic CD8+ T-cell epitopes of Cyfra21-1 were identified in a cohort of 150 NSCLC patients.
- These epitopes are restricted by prevalent HLA allotypes in the Northeast Asian population.
- A baseline count of reactive Cyfra21-1-specific CD8+ T cells in PBMCs independently predicted immunotherapy response (AUC=0.757).
- A cut-off value of 25.5 SFUs/4×10⁵ PBMCs distinguished responders from non-responders.
Conclusions:
- This study constructed the first broad-spectrum CD8+ T-cell epitope library for Cyfra21-1 in Northeast Asians.
- A universal assay for Cyfra21-1-specific CD8+ T-cell reactivity was established.
- Cyfra21-1-specific CD8+ T cells serve as a valuable, non-invasive predictor of immunotherapy response in NSCLC.
