Dataset Information

Fusion of Bacterial Flagellin to a Dendritic Cell-Targeting ?CD40 Antibody Construct Coupled With Viral or Leukemia-Specific Antigens Enhances Dendritic Cell Maturation and Activates Peptide-Responsive T Cells.

ABSTRACT: Conventional dendritic cell (DC) vaccine strategies, in which DCs are loaded with antigens ex vivo, suffer biological issues such as impaired DC migration capacity and laborious GMP production procedures. In a promising alternative, antigens are targeted to DC-associated endocytic receptors in vivo with antibody-antigen conjugates co-administered with toll-like receptor (TLR) agonists as adjuvants. To combine the potential advantages of in vivo targeting of DCs with those of conjugated TLR agonists, we generated a multifunctional antibody construct integrating the DC-specific delivery of viral- or tumor-associated antigens and DC activation by TLR ligation in one molecule. We validated its functionality in vitro and determined if TLR ligation might improve the efficacy of such a molecule. In proof-of-principle studies, an ?CD40 antibody containing a CMV pp65-derived peptide as an antigen domain (?CD40^CMV) was genetically fused to the TLR5-binding D0/D1 domain of bacterial flagellin (?CD40.Flg^CMV). The analysis of surface maturation markers on immature DCs revealed that fusion of flagellin to ?CD40^CMV highly increased DC maturation (3.4-fold elevation of CD80 expression compared to ?CD40^CMV alone) by specifically interacting with TLR5. Immature DCs loaded with ?CD40.Flg^CMV induced significantly higher CMV_NLV-specific T cell activation and proliferation compared to ?CD40^CMV in co-culture experiments with allogeneic and autologous T cells (1.8-fold increase in % IFN-?/TNF-?⁺ CD8⁺ T cells and 3.9-fold increase in % CMV_NLV-specific dextramer⁺ CD8⁺ T cells). More importantly, we confirmed the beneficial effects of flagellin-dependent DC stimulation using a tumor-specific neoantigen as the antigen domain. Specifically, the acute myeloid leukemia (AML)-specific mutated NPM1 (mNPM1)-derived neoantigen CLAVEEVSL was delivered to DCs in the form of ?CD40^mNPM1 and ?CD40.Flg^mNPM1 antibody constructs, making this study the first to investigate mNPM1 in a DC vaccination context. Again, ?CD40.Flg^mNPM1-loaded DCs more potently activated allogeneic mNPM1_CLA-specific T cells compared to ?CD40^mNPM1. These in vitro results confirmed the functionality of our multifunctional antibody construct and demonstrated that TLR5 ligation improved the efficacy of the molecule. Future mouse studies are required to examine the T cell-activating potential of ?CD40.Flg^mNPM1 after targeting of dendritic cells in vivo using AML xenograft models.

SUBMITTER: Schmitt S

PROVIDER: S-EPMC7689061 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Fusion of Bacterial Flagellin to a Dendritic Cell-Targeting αCD40 Antibody Construct Coupled With Viral or Leukemia-Specific Antigens Enhances Dendritic Cell Maturation and Activates Peptide-Responsive T Cells.

Schmitt Saskia S Tahk Siret S Lohner Alina A Hänel Gerulf G Maiser Andreas A Hauke Martina M Patel Lubna L Rothe Maurine M Josenhans Christine C Leonhardt Heinrich H Griffioen Marieke M Deiser Katrin K Fenn Nadja C NC Hopfner Karl-Peter KP Subklewe Marion M

Frontiers in immunology 20201112

Conventional dendritic cell (DC) vaccine strategies, in which DCs are loaded with antigens ex vivo, suffer biological issues such as impaired DC migration capacity and laborious GMP production procedures. In a promising alternative, antigens are targeted to DC-associated endocytic receptors in vivo with antibody-antigen conjugates co-administered with toll-like receptor (TLR) agonists as adjuvants. To combine the potential advantages of in vivo targeting of DCs with those of ...[more]

PMID: 33281829

Similar Datasets

Project description:Dendritic cells (DCs) are antigen-presenting cells essential for the induction of adaptive immune responses. Their unprecedented ability to present antigens to T cells has made them excellent targets for vaccine development. In the last years, a new technology based on antigen delivery directly to different DC subsets through the use of hybrid monoclonal antibodies (mAbs) to DC surface receptors fused to antigens of interest opened new perspectives for the induction of robust immune responses. Normally, the hybrid mAbs are administered with adjuvants that induce DC maturation. In this work, we targeted an antigen to the CD8?+ or the CD8?- DC subsets in the presence of CpG oligodeoxinucleotides (ODN) or bacterial flagellin, using hybrid ?DEC205 or ?DCIR2 mAbs, respectively. We also accessed the role of toll-like receptors (TLRs) 5 and 9 signaling in the induction of specific humoral and cellular immune responses. Wild-type and TLR5 or TLR9 knockout mice were immunized with two doses of the hybrid ?DEC205 or ?DCIR2 mAbs, as well as with an isotype control, together with CpG ODN 1826 or flagellin. A chimeric antigen containing the Plasmodium vivax 19?kDa portion of the merozoite surface protein (MSP119) linked to the Pan-allelic DR epitope was fused to each mAb. Specific CD4+ T cell proliferation, cytokine, and antibody production were analyzed. We found that CpG ODN 1826 or flagellin were able to induce CD4+ T cell proliferation, CD4+ T cells producing pro-inflammatory cytokines, and specific antibodies when the antigen was targeted to the CD8?+ DC subset. On the other hand, antigen targeting to CD8?- DC subset promoted specific antibody responses and proliferation, but no detectable pro-inflammatory CD4+ T cell responses. Also, specific antibody responses after antigen targeting to CD8?+ or CD8?- DCs were reduced in the absence of TLR9 or TLR5 signaling, while CD4+ T cell proliferation was mainly affected after antigen targeting to CD8?+ DCs and in the absence of TLR9 signaling. These results extend our understanding of the modulation of specific immune responses induced by antigen targeting to DCs in the presence of different adjuvants. Such knowledge may be useful for the optimization of DC-based vaccines.

Project description:Immunotherapy, which is seen as a major tool for cancer treatment, requires, in some cases, the presence of several agents to maximize its effects. Adjuvants can enhance the effect of other agents. However, despite their long-time use, only a few adjuvants are licensed today, and their use in cancer treatment is rare. Azoximer bromide, marketed under the trade name Polyoxidonium® (PO), is a copolymer of N-oxidized 1,4-ethylenepiperazine and (N-carboxyethyl)-1,4-ethylene piperazinium bromide. It has been described as an immune adjuvant and immunomodulator that is clinically used with excellent tolerance. PO is used in the treatment and prophylaxis of diseases connected with damage to the immune system, and there is interest in testing it in antitumor therapy. We show here that PO treatment for 1 week induced positive pathological changes in 6 out of 20 patients with breast cancer, including complete response in a triple-negative patient. This correlated with an increased tumor CD4+ T-lymphocyte infiltration. The immune effects of PO are associated with myeloid cell activation, and little is known about the action of PO on lymphocyte lineages, such as natural killer (NK) and T cells. We reveal that PO increases T-cell proliferation in vitro without negative effects on any activation marker. PO does not affect dendritic cell (DC) viability and increases the expansion of immature DC (iDC) and mature DC (mDC) at 100 μg/ml, and it stimulates expression of several DC co-stimulatory molecules, inducing the proliferation of allogeneic T cells. In contrast, PO decreases DC viability when added at day 5 post-expansion. PO is not toxic for NK cells at doses up to 100 μM and does not affect their activation, maturation, and cytotoxicity but tends to increase degranulation. This could be beneficial against target cells that show low sensitivity to NK cells, e.g., solid tumor cells. Finally, we have found great variability in PO response between donors. In summary, our in vitro results show that PO increases the number of costimulatory molecules on DC that prime T cells, favoring the production of effector T cells. This may support the future clinical development of PO in cancer treatment.

Dataset Information

Fusion of Bacterial Flagellin to a Dendritic Cell-Targeting ?CD40 Antibody Construct Coupled With Viral or Leukemia-Specific Antigens Enhances Dendritic Cell Maturation and Activates Peptide-Responsive T Cells.

Publications

Fusion of Bacterial Flagellin to a Dendritic Cell-Targeting αCD40 Antibody Construct Coupled With Viral or Leukemia-Specific Antigens Enhances Dendritic Cell Maturation and Activates Peptide-Responsive T Cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure