| 1. |
- Fletcher, Erika, et al.
(författare)
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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
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Ingår i: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 201:1, s. 87-97
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Fletcher, Erika, et al.
(författare)
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Formation ofimmune-complexes by a defined linear tetanus toxin-derived B cell epitope boosts human T cell responses to long peptides : ICs boost specific-T cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Enhancing T cell responses against both viral and tumor antigens requires efficient co-stimulation and directed delivery of peptide antigens into APCs. As short peptides can lead to T cell tolerance and can only be used in a specific set of patients, long peptides are considered favourable vaccine moieties from a clinical perspective as they can harbor more than one immunogenic epitope enabling a broader target population. In addition, longer peptides are not bound unselectively to MHC class I on any cell, but rather require processing and will thereby be presented to T cells in secondary lymphoid organs. However, as peptides are not actively targeted to and taken up by APCs, and the standard non-conjugated adjuvant-peptide mixtures do not ensure co-targeting of the two to the same APC. We have identified a linear tetanus-toxin derived B cell epitope that can mediate the formation of immune-complexes by the presence of circulating antibodies. Herein, we show that these complexes, improve both antigen uptake by APCs (blood monocytes and CD1c+ DCs) and thereby 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 antibodies and the complement component C1q. The defined linear peptide steers the immune-complex formation to a monoclonal-like complex and as a consequence we show that the number of linear tetanus sequences per T cell epitope determines the outcome of the response. We envision that this strategy can be used to facilitate active uptake of antigens into antigen-presenting cells to improve T cell responses against pathogens or cancer.
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| 3. |
- Lövgren, Tanja, et al.
(författare)
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Enhanced stimulation of human tumor-specific T cells by dendritic cells matured in the presence of interferon-gamma and multiple toll-like receptor agonists
- 2017
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Ingår i: Cancer Immunology and Immunotherapy. - : SPRINGER. - 0340-7004 .- 1432-0851. ; 66:10, s. 1333-1344
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Tidskriftsartikel (refereegranskat)abstract
- Dendritic cell (DC) vaccines have been demonstrated to elicit immunological responses in numerous cancer immunotherapy trials. However, long-lasting clinical effects are infrequent. We therefore sought to establish a protocol to generate DC with greater immunostimulatory capacity. Immature DC were generated from healthy donor monocytes by culturing in the presence of IL-4 and GM-CSF and were further differentiated into mature DC by the addition of cocktails containing different cytokines and toll-like receptor (TLR) agonists. Overall, addition of IFN gamma and the TLR7/8 agonist R848 during maturation was essential for the production of high levels of IL-12p70 which was further augmented by adding the TLR3 agonist poly I:C. In addition, the DC matured with IFN gamma, R848, and poly I:C also induced upregulation of several other pro-inflammatory and Th1-skewing cytokines/chemokines, co-stimulatory receptors, and the chemokine receptor CCR7. For most cytokines and chemokines the production was even further potentiated by addition of the TLR4 agonist LPS. Concurrently, upregulation of the anti-inflammatory cytokine IL-10 was modest. Most importantly, DC matured with IFN gamma, R848, and poly I:C had the ability to activate IFN gamma production in allogeneic T cells and this was further enhanced by adding LPS to the cocktail. Furthermore, epitope-specific stimulation of TCR-transduced T cells by peptide- or whole tumor lysate-loaded DC was efficiently stimulated only by DC matured in the full maturation cocktail containing IFN gamma and the three TLR ligands R848, poly I:C, and LPS. We suggest that this cocktail is used for future clinical trials of anti-cancer DC vaccines.
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| 4. |
- Mangsbo, Sara, 1981-, et al.
(författare)
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Linking T cell epitopes to a common linear B cell epitope : A targeting and adjuvant strategy to improve T cell responses
- 2018
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 93, s. 115-124
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Tidskriftsartikel (refereegranskat)abstract
- Immune complexes are potent mediators of cellular immunity and have been extensively studied for their disease mediating properties in humans and for their role in anti-cancer immunity. However, a viable approach to use antibody-complexed antigen as vehicle for specific immunotherapy has not yet reached clinical use. Since virtually all people have endogenous antibodies against tetanus toxoid (TTd), such commonly occurring antibodies are promising candidates to utilize for immune modulation. As an initial proof-of-concept we investigated if anti tetanus IgG could induce potent cross-presentation of a conjugate with SIINFEKL, a MHC class I presented epitope of ovalbumin (OVA), to TTd. This protein conjugate enhanced OVA-specific CD8 + T cell responses when administrated to seropositive mice. Since TTd is poorly defined, we next investigated whether a synthetic peptide peptide conjugate, with a chemically defined linear B cell epitope of tetanus toxin (TTx) origin, could improve cellular immune responses. Herein we identify one linear B cell epitope, here after named MTTE thru a screening of overlapping peptides from the alpha and beta region of TTx, and by assessment of the binding of pooled IgG, or individual human IgG from high-titer TTd vaccinated donors, to these peptides. Subsequently, we developed a chemical protocol to synthesize defined conjugates containing multiple copies of MITE covalently attached to one or more T cell epitopes of choice. To demonstrate the potential of the above approach we showed that immune complexes of anti-MITE antibodies with KM-containing conjugates are able to induce DC and T cell activation using model antigens.
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| 5. |
- Wickstrom, Stina L., et al.
(författare)
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Cancer Neoepitopes for Immunotherapy : Discordance Between Tumor-Infiltrating T Cell Reactivity and Tumor MHC Peptidome Display
- 2019
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Tumor-infiltrating lymphocytes (TIL) are considered enriched for T cells recognizing shared tumor antigens or mutation-derived neoepitopes. We performed exome sequencing and HLA-A*02:01 epitope prediction from tumor cell lines from two HLA-A2-positive melanoma patients whose TIL displayed strong tumor reactivity. The potential neoepitopes were screened for recognition using autologous TIL by immunological assays and presentation on tumor major histocompatibility complex class I (MHC-I) molecules by Poisson detection mass spectrometry (MS). TIL from the patients recognized 5/181 and 3/49 of the predicted neoepitopes, respectively. MS screening detected 3/181 neoepitopes on tumor MHC-I from the first patient but only one was also among those recognized by TIL. Consequently, TIL enriched for neoepitope specificity failed to recognize tumor cells, despite being activated by peptides. For the second patient, only after IFN-gamma treatment of the tumor cells was one of 49 predicted neoepitopes detected by MS, and this coincided with recognition by TIL sorted for the same specificity. Importantly, specific T cells could be expanded from patient and donor peripheral blood mononuclear cells (PBMC) for all neoepitopes recognized by TIL and/or detected on tumor MHC-I. In summary, stimulating the appropriate inflammatory environment within tumors may promote neoepitope MHC presentation while expanding T cells in blood may circumvent lack of specific TIL. The discordance in detection between physical and functional methods revealed here can be rationalized and used to improve neoantigen-targeted T cell immunotherapy.
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