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The C-Terminal Domain of Nef^mut Is Dispensable for the CD8⁺ T Cell Immunogenicity of In Vivo Engineered Extracellular Vesicles.

ABSTRACT: Intramuscular injection of DNA vectors expressing the extracellular vesicle (EV)-anchoring protein Nef^mut fused at its C-terminus to viral and tumor antigens elicit a potent, effective, and anti-tolerogenic CD8⁺ T cell immunity against the heterologous antigen. The immune response is induced through the production of EVs incorporating Nef^mut-derivatives released by muscle cells. In the perspective of a possible translation into the clinic of the Nef^mut-based vaccine platform, we aimed at increasing its safety profile by identifying the minimal part of Nef^mut retaining the EV-anchoring protein property. We found that a C-terminal deletion of 29-amino acids did not affect the ability of Nef^mut to associate with EVs. The EV-anchoring function was also preserved when antigens from both HPV16 (i.e., E6 and E7) and SARS-CoV-2 (i.e., S1 and S2) were fused to its C-terminus. Most important, the Nef^mut C-terminal deletion did not affect levels, quality, and diffusion at distal sites of the antigen-specific CD8⁺ T immunity. We concluded that the C-terminal Nef^mut truncation does not influence stability, EV-anchoring, and CD8⁺ T cell immunogenicity of the fused antigen. Hence, the C-terminal deleted Nef^mut may represent a safer alternative to the full-length isoform for vaccines in humans.

SUBMITTER: Chiozzini C

PROVIDER: S-EPMC8068889 | biostudies-literature |

REPOSITORIES: biostudies-literature

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