Introduction to T Cell Receptor Engineering by Yeast Display

In 1988, Dr. Michael Steinmetz reported the transfer of the T-cell receptor (TCR) gene from one T cell to another so that the second T cell would have the same antigenic specificity. This is the origin of TCR gene therapy. The TCR used for TCR antibody drugs and cell therapy needs to be engineered to achieve the desired specific tumor killing effect and safety. Therefore, the modification of TCR is the basis for the development of TCR antibody drugs and TCR for cell therapy. Based on our rich experience and advanced yeast display platform, Creative Biolabs provides comprehensive services to support antibody discovery by yeast display.

Yeast Display-Based T Cell Receptor Engineering

There are two main purposes of TCR engineering. The first is to ensure the correct pairing of the α and β chains of the TCR. The heterodimeric composition of the TCR results in the mispairing of α and β chains between the T cell's own TCR and the exogenously transferred TCR. The mismatch that occurs in the TCR not only reduces the level of functional exogenous TCRs on the surface of the T cell, but may also create the risk of attacking its own antigens. Currently, some strategies have been identified to address this problem, including down-regulation of the TCR expression using siRNA or knockdown of its own TCR by gene editing, increased disulfide bonding, murinization of the constant structural domains of the TCR α and β chains, or use of the TCR γδ structural domains in TCR βα to improve the pairwise binding of the TCRs. The second objective is to increase the affinity of TCRs for pMHC. While natural TCRs in vivo exhibit similar genetic and sequence diversity as antibodies, the binding affinity of TCRs is orders of magnitude lower than that of antibodies. Antibodies typically bind their cognate antigens at KD values in the nM or pM range. In contrast, TCRs bind peptide-MHC complexes (p-MHC) with low (micromolar) affinity. This is due to the absence of somatic mutation and affinity maturation of T cells during thymic development and maturation and to the fact that T cells with TCRs that bind too strongly to cognate antigens are eliminated by negative selection, whereas those that bind too weakly are eliminated by apoptosis. This editing mechanism significantly reduces the risk of autoimmune diseases but also limits the ability of the natural immune system to recognize TAA, since in most cases these peptides originate from autoproteins that are re-expressed or overexpressed in tumors. In general, the binding affinity of the TCR for cancer-associated antigens that are "self" antigens is about 10-fold lower than the binding affinity of the TCR for non-self and microbial antigens.

Yeast display technology has unique advantages in the field of TCR engineering. In specific experiments, TCR engineering modification can be effectively realized by setting the conditions for yeast display library construction and yeast display library screening, such as affinity maturation of TCRs by localization mutation, preparation of scTCR targeted mutation libraries by SOE PCR of scFvs, p-MHC selection, and screening of scTCRs with higher affinity.

Creative Biolabs has a wealth of knowledge and experience in yeast display. We would be happy to share with you our knowledge and experience on TCR engineering by yeast display.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.

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