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Biology subjects

Witwer, M. H.

Publications and source records attributed to Witwer, M. H..

2 recordsLinked to original sources

Function-preserving CD8⁺ T Cell Immunogenicity minimization through protein design

Rapid advances in protein design enable new approaches in adoptive cell therapy, but foreign proteins can elicit cytotoxic T cell responses, and hence there is considerable need for approaches which reduce immunogenicity without compromising protein function. Here, we develop a computational framework integrating structure-guided sequence design with MHC class I epitope prediction to efficiently tune protein immunogenicity while preserving function. Using a de novo-designed luciferase as a model, we demonstrate epitope elimination while preserving function across 5 common mouse alleles and extend our computational optimization to 25 common human MHC-I alleles. In mice immunized with mRNA-lipid nanoparticles, variants designed to have few MHC-I epitopes elicited little detectable CD8 T cell response, whereas variants designed to include multiple epitopes induced robust responses. Together, these results demonstrate that the CD8 T cell immunogenicity of designed proteins can be tuned while preserving function, opening the door to incorporation of designed proteins in a next generation of adoptive cell therapies.

bioengineering↗

Systems-Scale Structural Modeling Reveals the Germline Architecture of Immunodominance

The adaptive immune system generates diverse antibodies to protect against infection, yet responses often focus on a limited number of antigenic sites, a phenomenon called immunodominance. Using the SARS-CoV-2 receptor-binding domain as a model, this study combines large-scale antibody sequencing, deep mutational scanning, and AlphaFold 3 structural modeling to investigate the basis of immunodominant epitope selection. The results show that germline-encoded antibody features are a primary driver of immunodominance. Specifically, 76% of RBD-targeting antibodies display conserved gene segment usage and/or germline-encoded HCDR3 motifs. Structural analyses identified recurrent germline-encoded residues within these regions that interact with immunodominant epitopes, and mutating these residues eliminated binding. Mutations in SARS-CoV-2 variants frequently disrupt these interactions and are associated with immune escape; other mutations enable germline-mediated recognition and generate new immunodominant epitopes. These findings indicate that innate features, rather than diverse somatic mutations, determine binding specificity for the large majority of the antibody response and underlie antibody immunodominance.

immunology↗