Prevention of cytotoxic T cell escape using a heteroclitic subdominant viral T cell determinant.Butler, N.S., Theodossis, A., Webb, A.I., Nastovska, R., Ramarathinam, S.H., Dunstone, M.A., Rossjohn, J., Purcell, A.W., Perlman, S.
(2008) Plos Pathog. 4: --
- PubMed: 18949029
- DOI: 10.1371/journal.ppat.1000186
- Primary Citation of Related Structures:
- PubMed Abstract:
High affinity antigen-specific T cells play a critical role during protective immune responses. Epitope enhancement can elicit more potent T cell responses and can subsequently lead to a stronger memory pool; however, the molecular basis of such enha ...
High affinity antigen-specific T cells play a critical role during protective immune responses. Epitope enhancement can elicit more potent T cell responses and can subsequently lead to a stronger memory pool; however, the molecular basis of such enhancement is unclear. We used the consensus peptide-binding motif for the Major Histocompatibility Complex molecule H-2K(b) to design a heteroclitic version of the mouse hepatitis virus-specific subdominant S598 determinant. We demonstrate that a single amino acid substitution at a secondary anchor residue (Q to Y at position 3) increased the stability of the engineered determinant in complex with H-2K(b). The structural basis for this enhanced stability was associated with local alterations in the pMHC conformation as a result of the Q to Y substitution. Recombinant viruses encoding this engineered determinant primed CTL responses that also reacted to the wildtype epitope with significantly higher functional avidity, and protected against selection of virus mutated at a second CTL determinant and consequent disease progression in persistently infected mice. Collectively, our findings provide a basis for the enhanced immunogenicity of an engineered determinant that will serve as a template for guiding the development of heteroclitic T cell determinants with applications in prevention of CTL escape in chronic viral infections as well as in tumor immunity.
Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America.