| 1. |
- Westlund, Jessica, et al.
(författare)
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CD47-deficient mice have decreased production of intestinal IgA following oral immunization but a maintained capacity to induce oral tolerance.
- 2012
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Ingår i: Immunology. - Malden : Wiley. - 1365-2567 .- 0019-2805. ; 135:3, s. 236-44
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Tidskriftsartikel (refereegranskat)abstract
- Signal regulatory protein α (SIRPα/CD172a), expressed by myeloid cells including CD11b(+) dendritic cells, interacts with ubiquitously expressed CD47 to mediate cell-cell signalling and therefore, may be pivotal in the development of tolerance or immunity. We show that in mice deficient in CD47 (CD47(-/-) ) the cellularity in gut-associated lymphoid tissues is reduced by 50%. In addition, the frequency of CD11b(+) CD172a(+) dendritic cells is significantly reduced in the gut and mesenteric lymph nodes, but not in Peyer's patches. Activation of ovalbumin (OVA)-specific CD4(+) T cells in the mesenteric lymph nodes after feeding OVA is reduced in CD47(-/-) mice compared with wild-type however, induction of oral tolerance is maintained. The addition of cholera toxin generated normal serum anti-OVA IgG and IgA titres but resulted in reduced intestinal anti-OVA IgA in CD47(-/-) mice. Replacing the haematopoietic compartment in CD47(-/-) mice with wild-type cells restored neither the cellularity in gut-associated lymphoid tissues nor the capacity to produce intestinal anti-OVA IgA following immunization. This study demonstrates that CD47 signalling is dispensable for oral tolerance induction, whereas the expression of CD47 by non-haematopoietic cells is required for intestinal IgA B-cell responses. This suggests that differential CD4 T cell functions control tolerance and enterotoxin-induced IgA immunity in the gut.
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| 2. |
- Akeus, Paulina, et al.
(författare)
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Altered chemokine production and accumulation of regulatory T cells in intestinal adenomas of APC(Min/+) mice.
- 2014
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Ingår i: Cancer immunology, immunotherapy : CII. - : Springer Science and Business Media LLC. - 1432-0851 .- 0340-7004. ; 63:8, s. 807-19
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Tidskriftsartikel (refereegranskat)abstract
- Tumor progression in the colon moves from aberrant crypt foci to adenomatous polyps to invasive carcinomas. The composition of the tumor-infiltrating leukocyte population affects the ability of the immune system to fight the tumor. T cell infiltration into colorectal adenocarcinomas, particularly T helper 1 (Th1) type T cells as well as increased regulatory T cell (Treg) frequencies, is correlated with improved prognosis. However, whether Th1 cells and Tregs are already present at the adenoma stage is not known. In this study, the APC(Min/+) mouse model of intestinal adenomatous polyposis was used to investigate tumor-associated lymphocyte subsets and the mechanisms of their accumulation into gastrointestinal adenomas. Compared to unaffected tissue, adenomas accumulated CD4(+)FoxP3(+) putative Treg in parallel with lower frequencies of conventional T cells and B cells. The accumulation of Treg was also observed in human adenomatous polyps. Despite high Treg numbers, the function of conventional T cells present in the APC(Min/+) adenomas was not different from those in the unaffected tissue. Adenomas displayed an altered chemokine balance, with higher CCL17 and lower CXCL11 and CCL25 expression than in the unaffected tissue. In parallel, CXCR3(+) Tregs were largely absent from adenomas. The data indicate that already in early stages of tumor development, the balance of lymphocyte-recruiting chemokines is altered possibly contributing to the observed shift toward higher frequencies of Treg.
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| 3. |
- Cerovic, V, et al.
(författare)
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Intestinal CD103(-) dendritic cells migrate in lymph and prime effector T cells.
- 2013
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Ingår i: Mucosal immunology. - : Elsevier BV. - 1935-3456 .- 1933-0219. ; 6:1, s. 104-13
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Tidskriftsartikel (refereegranskat)abstract
- Intestinal dendritic cells (DCs) continuously migrate through lymphatics to mesenteric lymph nodes where they initiate immunity or tolerance. Recent research has focused on populations of intestinal DCs expressing CD103. Here we demonstrate, for the first time, the presence of two distinct CD103(-) DC subsets in intestinal lymph. Similar to CD103(+) DCs, these intestine-derived CD103(-) DCs are responsive to Flt3 and they efficiently prime and confer a gut-homing phenotype to naive T cells. However, uniquely among intestinal DCs, CD103(-) CD11b(+) CX(3)CR1(int) lymph DCs induce the differentiation of both interferon-γ and interleukin-17-producing effector T cells, even in the absence of overt stimulation. Priming by CD103(-) CD11b(+) DCs represents a novel mechanism for the rapid generation of effector T-cell responses in the gut. Therefore, these cells may prove to be valuable targets for the treatment of intestinal inflammation or in the development of effective oral vaccines.
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| 4. |
- Gustafsson, Tobias, et al.
(författare)
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Direct interaction between cholera toxin and dendritic cells is required for oral adjuvant activity
- 2013
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 43:7, s. 1779-1788
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Tidskriftsartikel (refereegranskat)abstract
- Cholera toxin (CT) binds to GM1-ganglioside receptors present on all nucleated cells. Despite this, it is a very potent mucosal adjuvant that has a dramatic impact on immune cells, as well as nerve and epithelial cells, causing diarrhea. This fact has hampered our understanding of whether the adjuvanticity of CT is direct or indirect, as cells that bind CT may or may not be involved in its adjuvant function. The mucosal barrier is maintained by tight junctions between epithelial cells but dendritic cells (DCs) can protrude luminal dendrites. Here we investigated which cells are involved in the immune augmenting effect of CT. We explored oral immunizations with ovalbumin (OVA) and CT in bone marrow chimeric mice deficient in GM1-ganglioside in defined cellular subsets. We found that chimeric mice lacking GM1 in nonhematopoietic cells, including epithelial cells, mounted an unaltered intestinal IgA response. In contrast, chimeric mice lacking GM1-expressing hematopoietic cells in general, or specifically GM1-expressing conventional DCs (cDCs), largely failed to elicit anti-OVA adaptive immune responses. Therefore, the adjuvanticity of CT does not require epithelial activation, but is directly dependent on the binding of CT to gut cDCs via GM1-ganglioside. These results could have important implications for the generation of novel oral adjuvants.
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| 5. |
- Henning, Petra, 1974, et al.
(författare)
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The subcellular location of antigen expressed by adenoviral vectors modifies adaptive immunity but not dependency on cross-presenting dendritic cells.
- 2011
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Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 41:8, s. 2185-96
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Tidskriftsartikel (refereegranskat)abstract
- Adenoviral (Ad) vaccine vectors can generate protective immunity to various pathogens in animal studies. However, recent failures in clinical vaccine trials have underscored the need for a better understanding of how mucosal immune responses to Ad-encoded vaccine Ags are generated in vivo. In this study, we addressed whether directing Ad-encoded ovalbumin (OVA) to different subcellular compartments influences the generation of OVA-specific acquired immunity and the APCs required following i.n. immunization of mice. We show that both secreted and membrane-anchored OVA activate CD4(+) T cells, induce cytotoxic CD8(+) T lymphocytes (CTLs) and generate serum IgG. Additionally, vaginal IgG is induced when OVA is expressed at these subcellular locations, but only the secreted form generates a significant IgA response in the lungs. On the contrary, intracellular expression of OVA efficiently expands CD8(+) T cells but fails to activate CD4(+) T cells, results in poor CTL activity, and does not generate Abs. Finally, we show that regardless of the subcellular localization of OVA, conventional DCs (cDCs) are required for the activation of T cells. However, the direct transduction of conventional DCs is not essential. These findings have important implications for the improvement of Ad vector design and vaccine-induced mucosal immunity.
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| 6. |
- Lycke, Nils Y, 1954, et al.
(författare)
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The 18th Germinal Centre Meeting.
- 2014
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Ingår i: Scandinavian journal of immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 80:3, s. 159-60
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Mattsson, Johan, et al.
(författare)
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Complement activation and complement receptors on follicular dendritic cells are critical for the function of a targeted adjuvant.
- 2011
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 187:7, s. 3641-52
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Tidskriftsartikel (refereegranskat)abstract
- A detailed understanding of how activation of innate immunity can be exploited to generate more effective vaccines is critically required. However, little is known about how to target adjuvants to generate safer and better vaccines. In this study, we describe an adjuvant that, through complement activation and binding to follicular dendritic cells (FDC), dramatically enhances germinal center (GC) formation, which results in greatly augmented Ab responses. The nontoxic CTA1-DD adjuvant hosts the ADP-ribosylating CTA1 subunit from cholera toxin and a dimer of the D fragment from Staphylococcus aureus protein A. We found that T cell-dependent, but not -independent, responses were augmented by CTA1-DD. GC reactions and serum Ab titers were both enhanced in a dose-dependent manner. This effect required complement activation, a property of the DD moiety. Deposition of CTA1-DD to the FDC network appeared to occur via the conduit system and was dependent on complement receptors on the FDC. Hence, Cr2(-/-) mice failed to augment GC reactions and exhibited dramatically reduced Ab responses, whereas Ribi adjuvant demonstrated unperturbed adjuvant function in these mice. Noteworthy, the adjuvant effect on priming of specific CD4 T cells was found to be intact in Cr2(-/-) mice, demonstrating that the CTA1-DD host both complement-dependent and -independent adjuvant properties. This is the first demonstration, to our knowledge, of an adjuvant that directly activates complement, enabling binding of the adjuvant to the FDC, which subsequently strongly promoted the GC reaction, leading to augmented serum Ab titers and long-term memory development.
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| 8. |
- Milling, Simon, et al.
(författare)
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Subsets of migrating intestinal dendritic cells.
- 2010
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Ingår i: Immunological reviews. - : Wiley. - 1600-065X .- 0105-2896. ; 234:1, s. 259-67
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Forskningsöversikt (refereegranskat)abstract
- Dendritic cells (DCs) in the intestine are heterogeneous. Phenotypically different populations of conventional DCs have been identified in the intestinal lamina propria, Peyer's patches, and in the draining mesenteric lymph nodes, to which these DCs constitutively migrate. Markers used to identify these populations include major histocompatibility complex class II, CD11c, CD8 alpha, CD11b, and CD103. Extensive studies in rats, summarized here, which involved collection of migrating DCs by thoracic duct cannulation after mesenteric lymphadenectomy, have clearly demonstrated that the subsets of migrating intestinal lymph DCs have different functional properties. The subsets might play different roles in the induction of oral tolerance and in driving systemic immune responses after vaccination or intestinal stimulation with Toll-like receptor ligands. The use of these surgical techniques allows investigation of the functions of purified subsets of migrating DCs. However, in the rat, these studies are limited by the range of available reagents and are difficult to compare with data from other species in this fast-moving field. Recent refinements have enabled the collection of migrating intestinal DCs from mice; our initial results are described here. We believe that these studies will generate exciting data and have the potential to resolve important questions about the functions of migrating intestinal DC subsets.
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| 9. |
- Sedimbi, Sai Kiran, 1982, et al.
(författare)
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PAMP mediated activation of type II NKT cells
- 2011
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Ingår i: 6th International Symposium on CD1d and NK T cells, September 23-27, 2011, Chicago, IL, USA.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Type 2 NK T cells are known to have immuno-stimulatory/regulatory effects on innate and adaptive immune responses to infections, tumors and autoimmunity. However, there is a paucity of information regarding the mechanism of activation of type 2 NK T cells in various immune responses. We aim to identify the signals required for activation of type 2 NK T cells by pathogen associated molecular patterns (PAMPs). Using type 2 NK T cells from a transgenic mouse model (24αβ B6: over expressing Vα3.2/Vβ9 type 2 NK T cells), we performed co-culture experiments with enriched primary type 2 NK T cells and bone marrow derived dendritic cells (DC) from mice that were WT or harbouring various gene deletions. Several TLR ligands activated the type 2 NK T cells in the co-cultures. The experiments revealed that type 2 NK T cells were not activated directly by PAMPs, but required the presence of antigen presenting cells such as DC. Transwell experiments suggest that activation occurred in a cell-contact dependent fashion. Further, we find that IL12 was absolutely essential for activation, while type I interferons appear to be dispensible. Surprisingly, CD1d was not required for type 2 NK T cell activation by PAMPs. Our results suggest that in addition to IL-12, other DC mediated signals were required for the CD1d-independent activation of type 2 NK T cells by PAMPs. Ongoing studies are investigating further which signals are required for NKT cell activation and the type of immune response induced.
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| 10. |
- Semmrich, Monika, et al.
(författare)
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Directed antigen targeting in vivo identifies a role for CD103(+) dendritic cells in both tolerogenic and immunogenic T-cell responses.
- 2012
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Ingår i: Mucosal immunology. - : Elsevier BV. - 1935-3456 .- 1933-0219. ; 5:2, s. 150-60
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Tidskriftsartikel (refereegranskat)abstract
- The αE integrin chain CD103 identifies a subset of migratory dendritic cells (DCs) in the gut, lung, and skin. To gain further understanding of the function of CD103(+) DCs in regulating adaptive immunity in vivo, we coupled ovalbumin (OVA) to the CD103 antibody M290 (M290.OVA). Intraperitoneal injection of M290.OVA induced OVA-specific CD8(+) and CD4(+) T-cell proliferation in lymph nodes (LNs) of wild-type but not CD103(-/-) mice, or in mice depleted of CD11c(+) cells. In the absence of maturation stimuli, systemic antigen targeting to CD103(+) DCs led to tolerance of CD8(+) T cells, whereas coadministration of adjuvant induced cytotoxic T-lymphocyte (CTL) immunity and antibody production. Mucosal intratracheal application of M290.OVA also induced T-cell proliferation in mediastinal LNs, yet the functional outcome was tolerance that inhibited subsequent development of allergic airway inflammation and immunoglobulin E (IgE) responses to inhaled OVA. These findings identify antigen targeting to CD103(+) DCs as a potential strategy to regulate immune responses in nonlymphoid mucosal tissues.
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