Alanine-based spacers promote an efficient antigen processing and presentation in neoantigen polypeptide vaccines

Area of Science:

• Immunology
• Oncology
• Vaccine Development

Background:

• Neoantigens are patient-specific tumor antigens crucial for personalized cancer vaccines.
• Effective T cell responses require neoantigen presentation by antigen-presenting cells (APCs) via MHC-I or MHC-II.
• Current neoantigen vaccines often use peptide pools, primarily inducing CD4+ T cell responses.

Purpose of the Study:

• To evaluate the impact of linker sequences on MHC-I-dependent neoantigen presentation.
• To compare the efficiency of different linker types in processing and presenting neoantigens.
• To optimize strategies for enhancing CD8+ T cell responses in neoantigen-based vaccines.

Main Methods:

• Utilized an in vitro assay to assess MHC-I presentation of a model peptide (SIINFEKL).
• Investigated the effect of various linker sequences on the processing and presentation of concatenated neoantigens.
• Compared alanine-based linkers with the commonly used GGGS linker.

Main Results:

• Linker regions significantly influence the efficiency of neoantigen processing and MHC-I presentation.
• Peptide position and flanking regions had minimal impact on antigen presentation.
• Alanine-based linkers demonstrated superior peptide presentation compared to GGGS linkers.

Conclusions:

• Linker selection is critical for optimizing MHC-I presentation of concatenated neoantigens.
• Alanine-based linkers represent a promising strategy for enhancing CD8+ T cell responses in personalized cancer vaccines.
• This finding can guide the design of more effective DNA/RNA-based neoantigen vaccines.