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Updated: Aug 24, 2026

Identification of Rare Antigen-Specific T Cells from Mouse Lungs with Peptide:Major Histocompatibility Complex Tetramers
Published on: July 19, 2024
Identification and characterization of a T-helper peptide from carcinoembryonic antigen
Marta Ruiz1, Hiroya Kobayashi, Juan José Lasarte
1Facultad de Medicina y Clínica Universitaria, Fundación para la Investigación Médica Aplicada , Universidad de Navarra, Pamplona, Spain.
Purpose:
The purpose of this research was to identify promiscuous T-helper cell determinants (THd) from carcinoembryonic antigen (CEA) to be used to prime T-cell help for cancer therapy. CEA was selected because this antigen is expressed in an important variety of carcinomas.
Experimental Design:
Potential promiscuous THd from CEA were predicted using available computer algorithms. Predicted peptides were synthesized and tested in binding experiments to different HLA-DR molecules. Binder peptides were then used to prime T-cell responses both in vitro and in vivo.
Results:
Twenty 15-mer peptides from CEA were predicted to bind to different HLA-DR molecules. The promiscuous character of these peptides was demonstrated in binding experiments. Fifteen of 20 peptides tested were able to bind to HLA-DR4, but only CEA (625-639) was shown to be presented after processing of recombinant CEA. CEA (625-639) was also found to be presented by HLA-DR53. Moreover, immunization of HLA-DR4 transgenic mice with CEA (625-639) in conjunction with class I epitope OVA (257-264), induced a CTL response specific of OVA (257-264).
Conclusions:
CEA (625-639) might be a relevant promiscuous THd peptide for cancer therapy.

