| 1. |
- Kessler, Jan H., et al.
(author)
-
Antigen processing by nardilysin and thimet oligopeptidase generates cytotoxic T cell epitopes
- 2010
-
In: Nature Immunology. - : Springer Science and Business Media LLC. - 1529-2908 .- 1529-2916. ; 12:1, s. 45-53
-
Journal article (peer-reviewed)abstract
- Cytotoxic T lymphocytes (CTLs) recognize peptides presented by HLA class I molecules on the cell surface. The C terminus of these CTL epitopes is considered to be produced by the proteasome. Here we demonstrate that the cytosolic endopeptidases nardilysin and thimet oligopeptidase (TOP) complemented proteasome activity. Nardilysin and TOP were required, either together or alone, for the generation of a tumor-specific CTL epitope from PRAME, an immunodominant CTL epitope from Epstein-Barr virus protein EBNA3C, and a clinically important epitope from the melanoma protein MART-1. TOP functioned as C-terminal trimming peptidase in antigen processing, and nardilysin contributed to both the C-terminal and N-terminal generation of CTL epitopes. By broadening the antigenic peptide repertoire, nardilysin and TOP strengthen the immune defense against intracellular pathogens and cancer.
|
|
| 2. |
- van Montfoort, Nadine, et al.
(author)
-
Circulating specific antibodies enhance systemic cross-priming by delivery of complexed antigen to dendritic cells in vivo
- 2012
-
In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 42:3, s. 598-606
-
Journal article (peer-reviewed)abstract
- Increasing evidence suggests that antibodies can have stimulatory effects on T-cell immunity. However, the contribution of circulating antigen-specific antibodies on MHC class I cross-priming in vivo has not been conclusively established. Here, we defined the role of circulating antibodies in cross-presentation of antigen to CD8+ T cells. Mice with hapten-specific circulating antibodies, but naϊve for the T-cell antigen, were infused with haptenated antigen and CD8+ T-cell induction was measured. Mice with circulating hapten-specific antibodies showed significantly enhanced cross-presentation of the injected antigen compared with mice that lacked these antibodies. The enhanced cross-presentation in mice with circulating antigen-specific antibodies was associated with improved antigen capture by APCs. Importantly, CD11c+ APCs were responsible for the enhanced and sustained cross-presentation, although CD11c− APCs had initially captured a significant amount of the injected antigen. Thus, in vivo formation of antigen-antibody immune complexes improves MHC class I cross-presentation, and CD8+ T-cell activation, demonstrating that humoral immunity can aid the initiation of systemic cellular immunity. These findings have important implications for the understanding of the action of therapeutic antibodies against tumor-associated antigens intensively used in the clinic nowadays.
|
|
| 3. |
- van Montfoort, Nadine, et al.
(author)
-
Fcγ receptor IIb strongly regulates Fcγ receptor-facilitated T cell activation by dendritic cells
- 2012
-
In: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 189:1, s. 92-101
-
Journal article (peer-reviewed)abstract
- FcγR ligation by Ag-Ab immune complexes (IC) not only mediates effective Ag uptake, but also strongly initiates dendritic cell (DC) maturation, a requirement for effective T cell activation. Besides the activating FcγRI, FcγRIII, and FcγRIV, the inhibitory FcγRIIb is expressed on DCs. It is unclear how the ratio between signals from the activating FcγR and the inhibitory FcγRIIb determines the outcome of FcγR ligation on DCs. By microarray analysis, we compared the transcriptomes of steady state and IC-activated bone marrow-derived wild-type (WT) DCs expressing all FcγR or DCs expressing only activating FcγR (FcγRIIb knockout [KO]) or only the inhibitory FcγRIIb (FcR γ-chain KO). In WT DCs, we observed a gene expression profile associated with effective T cell activation, which was absent in FcR γ-chain KO, but strikingly more pronounced in FcγRIIb KO bone marrow-derived DCs. These microarray results, confirmed at the protein level for many cytokines and other immunological relevant genes, demonstrate that the transcriptome of IC-activated DCs is dependent on the presence of the activating FcγR and that the modulation of the expression of the majority of the genes was strongly regulated by FcγRIIb. Our data suggest that FcγRIIb-deficient DCs have an improved capacity to activate naive T lymphocytes. This was confirmed by their enhanced FcγR-dependent Ag presentation and in vivo induction of CD8(+) T cell expansion compared with WT DCs. Our findings underscore the potency of FcγR ligation on DCs for the effective induction of T cell immunity by ICs and the strong regulatory role of FcγRIIb.
|
|
| 4. |
- Melssen, Marit M., et al.
(author)
-
Peptide emulsions in incomplete Freund's adjuvant create effective nurseries promoting egress of systemic CD4(+) and CD8(+) T cells for immunotherapy of cancer
- 2022
-
In: Journal for ImmunoTherapy of Cancer. - : BMJ Publishing Group Ltd. - 2051-1426. ; 10:9
-
Research review (peer-reviewed)abstract
- Water-in-oil emulsion incomplete Freund's adjuvant (IFA) has been used as an adjuvant in preventive and therapeutic vaccines since its development. New generation, highly purified modulations of the adjuvant, Montanide incomplete seppic adjuvant (ISA)-51 and Montanide ISA-720, were developed to reduce toxicity. Montanide adjuvants are generally considered to be safe, with adverse events largely consisting of antigen and adjuvant dose-dependent injection site reactions (ISRs). Peptide vaccines in Montanide ISA-51 or ISA-720 are capable of inducing both high antibody titers and durable effector T cell responses. However, an efficient T cell response depends on the affinity of the peptide to the presenting major histocompatibility complex class I molecule, CD4(+) T cell help and/or the level of co-stimulation. In fact, in the therapeutic cancer vaccine setting, presence of a CD4(+) T cell epitope seems crucial to elicit a robust and durable systemic T cell response. Additional inclusion of a Toll-like receptor ligand can further increase the magnitude and durability of the response. Use of extended peptides that need a processing step only accomplished effectively by dendritic cells (DCs) can help to avoid antigen presentation by nucleated cells other than DC. Based on recent clinical trial results, therapeutic peptide-based cancer vaccines using emulsions in adjuvant Montanide ISA-51 can elicit robust antitumor immune responses, provided that sufficient tumor-specific CD4(+) T cell help is given in addition to CD8(+) T cell epitopes. Co-treatment with PD-1 T cell checkpoint inhibitor, chemotherapy or other immunomodulatory drugs may address local and systemic immunosuppressive mechanisms, and further enhance efficacy of therapeutic cancer peptide vaccines in IFA and its modern variants. Blinded randomized placebo-controlled trials are critical to definitively prove clinical efficacy. Mineral oil-based adjuvants for preventive vaccines, to tackle spread and severity of infectious disease, induce immune responses, but require more studies to reduce toxicity.
|
|
| 5. |
- Fletcher, Erika, et al.
(author)
-
Formation of Immune Complexes with a Tetanus-Derived B Cell Epitope Boosts Human T Cell Responses to Covalently Linked Peptides in an Ex Vivo Blood Loop System
- 2018
-
In: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 201:1, s. 87-97
-
Journal article (peer-reviewed)abstract
- Enhancing T cell responses against both viral and tumor Ags requires efficient costimulation and directed delivery of peptide Ags into APCs. Long peptide vaccines are considered favorable vaccine moieties from a clinical perspective, as they can harbor more than one immunogenic epitope enabling treatment of a broader target population. In addition, longer peptides are not extracellularly loaded on MHC class I; rather, they require intracellular processing and will thereby be presented to T cells mainly by professional APCs, thereby avoiding the risk of tolerance induction. The drawback of peptide vaccines regardless of peptide length is that naked peptides are not actively targeted to and taken up by APCs, and the standard nonconjugated adjuvant-peptide mixtures do not ensure cotargeting of the two to the same APC. We have identified a tetanus toxin-derived B cell epitope that can mediate the formation of immune complexes in the presence of circulating Abs. In this study, we show that these immune complexes improve both Ag uptake by APCs (blood monocytes and CD1c(+) dendritic cells) and consequently improve CD8(+) T cell recall responses in a human ex vivo blood loop system. The uptake of the peptide conjugate by blood monocytes is dependent on Abs and the complement component C1q. We envision that this strategy can be used to facilitate active uptake of Ags into APCs to improve T cell responses against pathogens or cancer.
|
|
