Development of a Versatile Cancer Vaccine Format Targeting Antigen-Presenting Cells Using Proximity-Based Sortase...

Area of Science:

• Immunology
• Biotechnology
• Oncology

Background:

• Cancer vaccines aim to boost anti-tumor immunity, especially in patients unresponsive to checkpoint inhibitors.
• Personalized cancer vaccines using patient-specific antigens are highly effective but complex to produce.
• Targeting antigen-presenting cells (APCs) with specific receptors like DEC205 and CD169 can enhance immune stimulation.

Purpose of the Study:

• To develop a versatile cancer vaccine platform enabling site-specific conjugation of tumor antigens.
• To utilize proximity-based Sortase A-mediated ligation (PBSL) for antigen attachment to APC-targeting antibodies.
• To create a rapid and adaptable method for synthesizing personalized cancer vaccines.

Main Methods:

• Engineered mouse IgG2a antibodies targeting DEC205 or CD169, incorporating Sortase A (SrtA) motifs and SpyTag.
• Utilized SrtA-SpyCatcher system for proximity-based SrtA-mediated ligation of antigens (FITC or peptides) to antibodies.
• Employed CRISPR/HDR for antibody engineering and assessed antibody binding and immune stimulation in vitro and in vivo.

Main Results:

• Successfully ligated antigens to DEC205- and CD169-specific antibodies using the PBSL approach.
• Demonstrated that the conjugated antibodies bind effectively to DEC205-expressing dendritic cells and CD169-expressing macrophages in vitro and in vivo.
• Showed that immunization with these antibody-antigen conjugates efficiently stimulated T-cell responses in vivo.

Conclusions:

• Developed a novel cancer vaccine format utilizing PBSL for rapid antigen incorporation.
• The platform enables site-specific conjugation of tumor antigens to APC-targeting antibodies.
• This approach holds promise for the efficient synthesis of personalized cancer vaccines.