Lambda Phage-Based Antibody-Stimulating Platform Targeting EGFRvIII

Background/Objectives: Bacteriophage-based display has been utilized for a variety of purposes, such as to assemble protein libraries and conduct biopanning. We have created a modified lambda (λ) bacteriophage platform, ideal for the display and delivery of proteins. Our system utilizes counter-selection recombineering for versatile modification, temperature-sensitive induction for timely lysate production, and an arabinose-inducible mechanism for high-titer, stable yield. Here, we investigated the ability of this specialized λ phage display platform to stimulate highly specific antibodies in mice against the displayed cancer-variant cell-surface receptor EGFRvIII, demonstrating its potential in cancer immunotherapy and broader vaccine development. Methods: λ display immunogenicity was explored by generating fusion proteins between the λ head protein D and a 13-mer peptide from the N terminus of glioblastoma variant cell-surface receptor, EGFRvIII. The 13-mer peptide was fused to either the N or C terminus of the λD protein while λ remained a dormant lysogen in the bacterial host chromosome. Recombinant phage lysates were then generated with ~420 displayed fusion proteins per phage particle. Mice were injected with purified recombinant λ phage without an adjuvant via both intraperitoneal and intramuscular routes, and sera harvested at various timepoints were profiled for immunogenicity. Results: Analysis of serum samples by ELISA and Western blotting demonstrated the ability of the λD~EGFRvIII phage display, especially in the C-terminal fusion construction, to elicit a robust anti-EGFRvIII humoral response by either injection route. Notably, the antibody response was highly specific to EGFRvIII without exhibiting cross-reactivity to wild-type EGFR. Conclusions: The data generated in this study demonstrate the λ system’s immunotherapeutic potential as a high-titer, stable, self-adjuvating vector for the stimulation of robust antibody titers with defined specificity.