| 1. |
- Wigren, Maria, et al.
(författare)
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Atheroprotective effects of Alum are associated with capture of oxidized LDL antigens and activation of regulatory T cells
- 2009
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Ingår i: Circulation Research. - 0009-7330 .- 1524-4571. ; 104:12, s. e62-70
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Tidskriftsartikel (refereegranskat)abstract
- The immune system represents a promising novel target for prevention of atherosclerosis. Several pilot vaccines that reduce atherosclerosis in experimental animals have been developed. The aluminum hydroxide adjuvant Alum has been shown to have antiatherogenic properties in itself, suggesting that it may be a suitable adjuvant in possible future atherosclerosis vaccines. To characterize the immune pathways mediating this protection, we treated wild-type C57BL/6 and Apoe(-)(/)(-) mice with Alum or PBS. Analyses of splenocytes isolated from 12-week-old mice demonstrated that Alum increased the presence of CD4(+)CD25(+)FoxP3(+) regulatory T cells and downregulated the expression of T cell activation markers CD28 and ICOS in Apoe(-)(/)(-) mice but not in C57BL/6 wild-type mice. A similar immunosuppressive phenotype was found also in 25-week-old Apoe(-)(/)(-) mice and was associated with reduced atherosclerosis. Alum precipitates recovered from the injection site of Apoe(-)(/)(-) mice contained antigens derived from oxidized LDL. These findings demonstrate that treatment of Apoe(-)(/)(-) mice with Alum results in an increase of regulatory T cells and suggest that these are activated by tolerogenic antigen-presenting cells presenting oxidized LDL antigens. Our findings provide improved mechanistic understanding of the atheroprotective properties of aluminum hydroxide adjuvants but also point to the importance of determining if hypercholesterolemia may compromise the efficacy of Alum-containing vaccines used clinically today.
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| 2. |
- Kolbus, Daniel
(författare)
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Adaptive immune responses in atherosclerosis - or how to prolong the use of your yellow socks
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Atherosclerosis is a multifactorial disease, but an unbalanced immune system plays a critical role in the disease development. A common theory states that a continuous stress to the vascular vessel wall initiates a repair process that however is insufficient to completely heal the tissue. This imbalance is associated with accumulation of cholesterol, which is an essential component of cellular membranes, and inflammatory cells at the injury site. Since cholesterol particles are not normally accumulating extra-cellularly, they are affected by the inflammatory environment, which modifies the particle structure. Since this can be potentially dangerous an inflammatory response is initiated in order to remove the modified particles. However, the continuous stress leads to an imbalanced immune response, which aggravate the inflammation and leads to a larger wound. In this thesis I present two methods on how to balance the immune response in order to stabilize the wound and thereby reduce the risk of rupture. I also elucidate the role of CD8+ T lymphocytes in the development of atherosclerotic lesions and test the association between CD8+ T lymphocytes in blood and cardiovascular disease.
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| 3. |
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| 4. |
- Kolbus, Daniel, et al.
(författare)
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Association between CD8+ T-cell subsets and cardiovascular disease
- 2013
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Ingår i: Journal of Internal Medicine. - : John Wiley & Sons. - 0954-6820 .- 1365-2796. ; 274:1, s. 41-51
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Tidskriftsartikel (refereegranskat)abstract
- Background The findings of experimental studies suggest that the immune system plays a key role in atherosclerosis, but the clinical importance of different immune cells in cardiovascular disease remains poorly characterized. In this study we investigated the association between CD8+ T cells and carotid disease as well as development of cardiovascular disease events. Methods The study cohort comprised 700 subjects from the cardiovascular arm of the Malmö Diet and Cancer Study. Peripheral blood mononuclear cells, obtained at the 1991–1994 baseline investigation and stored at −140 °C, were thawed and the different CD8+ T-cell populations analysed by flow cytometry. Baseline carotid intima–media thickness and stenosis were assessed by ultrasonography and clinical events were monitored through validated national registers. Results Subjects with a high fraction of CD8+ T cells were characterized by decreased cytokine release from activated leucocytes, metabolic signs of insulin resistance and increased incidence of coronary events; hazard ratios (95% confidence intervals) for the second and third tertiles of CD8+ T cells were 2.57 (1.16, 5.67) and 2.61 (1.19, 5,71), respectively, in a Cox proportional hazards regression model. Correlations were found between the fraction of CD8+CD25+ T cells and the degree of carotid stenosis (r = 0.11, P < 0.01), and between the CD8+CD56−IFN-γ+ T-cell fraction and the degree of stenosis (r = −0.18, P < 0.005). The association between CD8+CD56−IFN-γ+ T cells and carotid stenosis remained significant after controlling for major cardiovascular disease risk factors. Conclusion This study provides prospective clinical evidence for a role of CD8+ T cells in cardiovascular disease and suggests the existence of CD8+ T-cell subsets with different pathological functions.
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| 5. |
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| 6. |
- Kolbus, Daniel, et al.
(författare)
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CD8+ T cell activation predominate early immune responses to hypercholesterolemia in Apoe-/- mice.
- 2010
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Ingår i: BMC Immunology. - : Springer Science and Business Media LLC. - 1471-2172. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- It is well established that adaptive immune responses induced by hypercholesterolemia play an important role in the development of atherosclerosis, but the pathways involved remain to be fully characterized. In the present study we assessed immune responses to hypercholesterolemia induced by feeding Apoe-/- mice a high-fat diet for 4 or 8 weeks.
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| 7. |
- Kolbus, Daniel, et al.
(författare)
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Immunization with cationized BSA inhibits progression of disease in ApoBec-1/LDL receptor deficient mice with manifest atherosclerosis.
- 2011
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Ingår i: Immunobiology. - : Elsevier BV. - 1878-3279 .- 0171-2985. ; 216, s. 663-669
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Tidskriftsartikel (refereegranskat)abstract
- Immune responses against modified self-antigens generated by hypercholesterolemia play an important role in atherosclerosis identifying the immune system as a possible novel target for prevention and treatment of cardiovascular disease. It has recently been shown that these immune responses can be modulated by subcutaneous injection of adjuvant. In the present study we immunized 25-week old ApoBec-1/LDL receptor deficient mice with manifest atherosclerosis with adjuvant and two different concentrations of the carrier molecule cationized BSA (cBSA). Plasma levels of Th2-induced apolipoprotein B (apoB)/IgG1 immune complexes were increased in the cBSA immunized groups verifying induction of immunity against a self-antigen. Mice were sacrificed at 36 weeks of age and atherosclerosis was monitored by en face Oil red O staining of the aorta. Immunization with 100μg cBSA inhibited plaque progression, whereas the lower dose (50μg) did not. In addition, the higher dose induced a more stable plaque phenotype, indicated by a higher content of collagen and less macrophages and T cells in the plaques. Moreover, there was an increased ratio of Foxp3(+)/Foxp3(-) T cells in the circulation suggesting activation of a regulatory T cell response. In conclusion, we show that immunization with cBSA induces an immune response against apoB as well as an activation of Treg cells. This was associated with development of a more stable plaque phenotype and reduced atherosclerosis progression.
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| 8. |
- Kolbus, Daniel, et al.
(författare)
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TAP1-Deficiency Does Not Alter Atherosclerosis Development in Apoe−/− Mice
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 3:7
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Tidskriftsartikel (refereegranskat)abstract
- Antigen presenting cells (APC) have the ability to present both extra-cellular and intra-cellular antigens via MHC class I molecules to CD8+ T cells. The cross presentation of extra-cellular antigens is reduced in mice with deficient Antigen Peptide Transporter 1 (TAP1)-dependent MHC class I antigen presentation, and these mice are characterized by a diminished CD8+ T cell population. We have recently reported an increased activation of CD8+ T cells in hypercholesterolemic Apoe−/− mice. Therefore, this study included TAP1-deficient Apoe−/− mice (Apoe−/−Tap1−/−) to test the atherogenicity of CD8+ T cells and TAP1-dependent cross presentation in a hypercholesterolemic environment. As expected the CD8+ T cell numbers were low in Apoe−/−Tap1−/− mice in comparison to Apoe−/− mice, constituting ~1% of the lymphocyte population. In spite of this there were no differences in the extent of atherosclerosis as assessed by en face Oil Red O staining of the aorta and cross-sections of the aortic root between Apoe−/−Tap1−/− and Apoe−/− mice. Moreover, no differences were detected in lesion infiltration of macrophages or CD3+ T cells in Apoe−/−Tap1−/− compared to Apoe−/− mice. The CD3+CD4+ T cell fraction was increased in Apoe−/−Tap1−/− mice, suggesting a compensation for the decreased CD8+ T cell population. Interestingly, the fraction of CD8+ effector memory T cells was increased but this appeared to have little impact on the atherosclerosis development. In conclusion, Apoe−/−Tap1−/− mice develop atherosclerosis equal to Apoe−/− mice, indicating a minor role for CD8+ T cells and TAP1-dependent antigen presentation in the disease process.
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| 9. |
- Wigren, Maria, et al.
(författare)
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Evidence for a role of regulatory T cells in mediating the atheroprotective effect of apolipoprotein B peptide vaccine.
- 2011
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 269, s. 546-556
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Tidskriftsartikel (refereegranskat)abstract
- Abstract. Wigren M, Kolbus D, Dunér P, Ljungcrantz I, Söderberg I, Björkbacka H, Fredrikson GN, Nilsson J. (Malmö University Hospital, Lund University; Malmö University, Malmo; Sweden) Evidence for a role of regulatory T cells in mediating the atheroprotective effect of apolipoprotein B peptide vaccine. J Intern Med 2010; doi: 10.1111/j.13 65-2796.2010.02311.x. Objectives. Autoimmune responses against oxidized low-density lipoprotein are considered to play an important pro-inflammatory role in atherosclerosis and to promote disease progression. T-regulatory cells (Tregs) are immunosuppressive cells that have an important part in maintaining self-tolerance and protection against autoimmunity. We investigated whether aBp210, a prototype atherosclerosis vaccine based on a peptide sequence derived from apolipoprotein B, inhibits atherosclerosis through the activation of Tregs. Design. Six-week-old Apoe(-/-) mice were immunized with aBp210 and received booster immunizations 3 and 5 weeks later, as well as 1 week before being killed at 25 weeks of age. Results. At 12 weeks, immunized mice had increased expression of the Treg marker CD25 on circulating CD4 cells, and concanavalin A (Con A)-induced interferon-γ, interleukin (IL)-4, and IL-10 release from splenocytes was markedly depressed. At 25 weeks, there was a fivefold expansion of splenic CD4+ CD25+ Foxp3 Tregs, a 65% decrease in Con A-induced splenic T-cell proliferation and a 37% reduction in the development of atherosclerosis in immunized mice. Administration of blocking antibodies against CD25 neutralized aBp210-induced Treg activation as well as the reduction of atherosclerosis. Conclusions. The present findings demonstrate that immunization of Apoe(-/-) mice with the apolipoprotein B peptide vaccine aBp210 is associated with activation of Tregs. Administration of antibodies against CD25 results in depletion of Tregs and blocking of the atheroprotective effect of the vaccine. Modulation in atherosclerosis-related autoimmunity by antigen-specific activation of Tregs represents a novel approach for treatment of atherosclerosis.
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