Defining and predicting the peptide-MHC repertoire of the T cell receptor

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Abstract/Contents

Abstract
[alpha] [beta] T cells are central mediators of the adaptive immune system, tasked with cytotoxic functions and coordinating the B cell and innate immune responses. The T cell response relies upon the T cell receptor, rendered hugely diverse through V(D)J recombination, sampling peptides bound to MHC molecules to instill antigen specificity to the immune response. However, the number of possible peptide-MHC greatly outstrips the theoretical number of possible T cell receptors and surpasses the total number of T cells in any given organism by an even larger margin. The basis for how T cell receptors can be cross-reactive enough to ensure all possible antigens can be recognized while retaining enough specificity to avoid promiscuous T cell activation and autoimmunity has not been systematically examined. To address this, I harness a manmade system to generate large degrees of molecular diversity, yeast display (introduced in Chapter 1), to directly assay the degree and mechanism of T cell receptor cross reactivity. Upon exhaustively examining the peptide-MHC recognition repertoire for five T cell receptors (in Chapter 2), I find a surprisingly limited degree of diversity in the recognized sequences. Instead, cross-reactivity is accomplished via relatively conservative mutations in the T cell receptor contact epitope mated to a larger degree of mutation elsewhere in the presented peptide. Even the most seemingly diverse sequences recognized by any T cell receptor are recognized in structurally similar ways and can be connected via intermediate related sequences. I then leverage these close relationships to find naturally occurring peptide ligands for T cell receptors with a high rate of success. In Chapter 3, I further refine our system to find even lower affinity peptide-MHC ligands, relevant for T cell development, through evolving a piece of 'molecular velcro' that provides an additional point of attachment between the peptide and T cell receptor while preserving discrimination between binding and nonbinding peptides.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2014
Issuance monographic
Language English

Creators/Contributors

Associated with Birnbaum, Michael E
Associated with Stanford University, Program in Immunology.
Primary advisor Garcia, K. Christopher
Thesis advisor Garcia, K. Christopher
Thesis advisor Cochran, Jennifer R
Thesis advisor Davis, Mark
Thesis advisor Jardetzky, Theodore
Advisor Cochran, Jennifer R
Advisor Davis, Mark
Advisor Jardetzky, Theodore

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Michael E. Birnbaum.
Note Submitted to the Program in Immunology.
Thesis Thesis (Ph.D.)--Stanford University, 2014.
Location electronic resource

Access conditions

Copyright
© 2014 by Michael Edward Birnbaum
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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