A novel peptide targeting Clec9a on dendritic cell for cancer immunotherapy

Abstract

Dendritic cells (DCs) are professional antigen-presenting cells with antigen recognition molecules on the surface. Clec9a is selectively expressed on mouse CD8a+ DCs and CD103+ DCs subsets, which are functionally similar to human BDCA3+ DCs. It is reported that Clec9a is responsible for the antigen cross-presentation of these DC subsets. In the present study, by using phage display technique, we discovered a novel peptide WH, which can selectively bind to mouse Flt3L induced Clec9a+ DCs or Clec9a over-expressed HEK-293T cells. Furthermore, by using computer-aided docking model and mutation assay, we observed that Asp248 and Trp250 are two key residues for Clec9a to bind with peptide WH. When coupled with OVA257-264 epitope, peptide WH can significantly enhance the ability of Clec9a+ DCs to activate OVA-specific CD8+ T cells, which elicit strong ability to secret IFN-γ, express perforin and granzyme B mRNA. In B16-OVA lung metastasis mouse model, WH-OVA257-264 fusion peptide can also enhance the activation of CD8+ T cells and decrease the lung metastasis loci. All these results suggested that peptide WH could be considered as an antigen delivery carrier targeting Clec9a+ DCs for cancer immunotherapy.

Self-adjuvanting nanoemulsion targeting dendritic cell receptor Clec9A enables antigen-specific immunotherapy

“…inoculation without additional adjuvant, CTL induction requires systemic coadministration of agonist anti-CD40 and/or TLR-agonist adjuvant (22,24), which may increase the risk of systemic inflammatory adverse effects. An alternative approach used a peptide to target Clec9A + DCs with OVA 257-264 , but in vivo CTL priming also required adjuvant (25).…”

“…Since clinical translation may be hampered by immunogenicity of the Clec9A mAb, we exploited the highly conserved F-actin component of the cellular cytoskeleton and a recently described WH peptide as specific Clec9A ligands to functionalize nanoparticles targeting either mouse or human cross-presenting DCs (25,40). OVA-WH-TNE had a similar size distribution to OVA-Clec9A-TNE, and maintained stability in serum conditions when stored at 4°C for up to 25 days (Supplemental Figure 1C).…”

Dendritic Cells in Anticancer Vaccination: Rationale for Ex Vivo Loading or In Vivo Targeting

“…As there are still unknown ligands for Clec9A, its targeting in almost all studies was performed using Clec9A-specific antibodies. Recently, an analysis of the binding moieties of Clec9A was performed and a peptide that interacts with Clec9A was identified [128]. Accordingly, so-called WH synthetic peptide was produced and tested for Clec9A specificity and the ability to enhance the antigen-specific immune response.…”

DNGR-1, a Dendritic Cell-Specific Sensor of Tissue Damage That Dually Modulates Immunity and Inflammation

“…Targeting of antigens to DNGR-1 using antibodies allows for specific delivery to cDC1s (10,13,21), which excel at cross-presentation (22), resulting in improved cross-priming of CD8 + T cells when administered under the cover of an adjuvant (10). Alternatively, specific peptides selected by in vitro evolution systems and beads coated with a synthetic F-actin/myosin II complex can be used for in vivo targeting of antigens toward DNGR-1 (23,24). Moreover, anti-DNGR-1 antibodies can be used to deliver antigen-containing nanoemulsions with immunostimulatory properties (25).…”