T Cell Epitope Discovery with the T Cell Truncated Library

Overview

The T cell epitope is a small peptide sequence, presented by MHC receptors on antigen presenting cells and other nucleated cells, that stimulates immune system activity. For many diseases, such as viral diseases and cancer, T cells cannot adequately recognize virus or cancer-cell epitopes. Re-engineering the T cell receptor enables the T cell to recognize and bind these epitopes more efficiently. In doing so, we can stimulate the body's own immune system to target and fight diseases that normally are difficult to treat.

In most cases, immunotherapy first requires identification of the most immuno-stimulatory epitopes on viruses or cancer cells. The T cell epitopes are short peptide sequences, ranging from 8-11 amino acids in length on MHC I complexes and 15-24 amino acids on MHC II complexes. To identify these small peptide sequences within the larger epitope, peptide libraries are ideal, since they span hundreds of peptide combinations simultaneously. The T cell truncated peptide library is unique, in that it is composed of sequentially truncated peptide combinations, thereby ensuring that the entire T cell epitope is spanned. These truncated peptide fragments, commonly ranging from 11- to 8-mers, are pooled. Once a positive pool has been identified, the pool can be deconvoluted to identify the T cell epitope sequence.

To use GenScript's T cell truncated peptide library tool, first enter the protein sequence of interest. Then, select the length of the longest peptide sequence in the pool (for MHC I, this will be 11, while for MHC II the longest length can be up to 24 AA). The tool will generate pools of 11-mer, 10-mer-, 9-mer, and 8-mer peptides that span the entire sequence length (or for other peptide sequences, the lengths will be n-mer, (n-1)-mer, (n-2)-mer, and (n-3)-mer).

Applications of T-Cell Truncated Library

• Allow to test all possible T-cell epitopes across a protein of interest

Overlapping Peptide   Alanine Scanning       Truncation Library   Positional Scanning       Random Library   Scrambled Library       T Cell Truncated Library

References

• Franzoni G, Kurkure NV, Essler SE, Pedrera M, Everett HE, Bodman-Smith KB, Crooke HR, Graham SP. Proteome-wide screening reveals immunodominance in the CD8 T cell response against classical swine fever virus with antigen-specificity dependent on MHC class I haplotype expression. PLoS One. 2013 Dec 23;8(12):e84246.
• McGuide TC, Leib SR, Mealey RH, Fraser DG, Prieur DJ. Presentation and binding affinity of equine infectious anemia virus CTL envelope and matrix protein epitopes by an expressed equine classical MHC class I molecule. J Immunol. 2003 Aug 15;171(4):1984-93.
• Holtappels R, Lemmermann N, Thomas D, Renzaho A, Reddehase M. Identification of an atypical CD8 T cell epitope encoded by murine cytomegalovirus ORF-M54 gaining dominance after deletion of the immunodominant antiviral CD8 T cell specificities.  Med Microbiol Immunol. 2015; 2004: 317-326.
• Buhrman JD, Jordan KR, Munson DJ, Moore BL, Kappler JW, Slansky JE. Improving antigenic peptide vaccines for cancer immunotherapy using a dominant tumor-specific T cell receptor. J Biol Chem. 2013 Nov 15;288(46):33213-25.