However, stimulation of 4-1BB with an agonistic antibody improved atherosclerotic burden accompanied by enhanced lesional swelling whereas 4-1BB deficiency attenuates atherosclerosis in mice.163,164Advanced atherosclerotic lesions accumulated more macrophages and T cells when 4-1BB was missing.165Lesions in these mice showed indications of vulnerability, accompanied by reduced SMC survival and collagen production.165Interestingly, macrophage glucose metabolism is regulated from the interaction of 4-1BBL with its receptor, leading to increased metabolic activity and cell proliferation.166Thus, intervention in 4-1BB-4-BBL interactions might display a valuable therapeutic option in macrophage-driven diseases such as atherosclerosis. == 3.2.7 LIGHT HEVM == HVEM (herpes virus entry mediator, TNFRSF14) is expressed by resting T cells and APCs whereas its main ligand, LIGHT (TNFSF14), is expressed by activated T cells, monocytes, DCs, and NK cells.167,168HVEM can also interact with lymphotoxin-, BTLA (B and T lymphocyte attenuator), and CD160.169Interactions with LIGHT and lymphotoxin- contribute to T cell activation and cytokine production whereas ligation of HVEM to BTLA and CD160 promotes co-inhibitory effects.169The contribution of HVEM and LIGHT to atherosclerosis is not fully understood. brief intro to atherosclerosis == Atherosclerosis is a chronic inflammatory disease of the artery wall. The resulting medical events are the leading cause of death worldwide.1The factors contributing to atherosclerosis are multifaceted, encompassing environmental and genetic risk factors, perturbed cholesterol homeostasis, and a lingering immune response that all influence atherogenesis, plaque progression, vascular dysfunction and ultimately plaque rupture or erosion, the proximal causes of major adverse cardiovascular events (MACE).25Dyslipidemia and endothelial dysfunction promote the increased influx and retention of lipoprotein particles including low-density lipoprotein (LDL).6Adhesion molecules Ziyuglycoside II are expressed by activated endothelial cells (EC) preferentially at sites of disturbed blood flow.7,8Furthermore, the changes of retained lipoproteins (e.g. oxidation) can induce a low-grade immune response including activation activating endothelial cells.5,6Adhering leukocytes, predominately inflammatory monocytes, transmigrate into the subendothelial space, and contribute to the pro-inflammatory micromilieu by secretion of chemokines that further boost recruitment of monocytes, neutrophils, and lymphocytes from your circulation.9Some monocytes differentiate into macrophages that scavenge the trapped lipoprotein particles and transform into foam cells. In addition to their recruitment, macrophages can also undergo local proliferation. Yet, their egress may be prevented by retention signals, therefore also contributing to growth of the atherosclerotic lesion.10,11As the capacity to clear or store lipids is exceeded in these cells, they can undergo apoptosis. When the uptake of apoptotic cells (efferocytosis) fails these cells undergo secondary necrosis and form the acellular necrotic core of atherosclerotic lesions. Retained lipoprotein particles such as LDL undergo oxidation along with other modifications. This makes them ligands for scavenger receptors (SR) like CD36, SR-A, SR-B and toll-like receptors (TLRs), which activate numerous pro-inflammatory DEPC-1 signaling pathways that induce co-stimulatory molecules. Modified LDL presents lipid neoepitopes, the part of which in atherogenesis is Ziyuglycoside II definitely poorly recognized.12,13 Dendritic cells (DC) are key players in bridging innate and adaptive immunity. Lymph node and spleen DCs are most capable in showing antigen to nave T cells. A network of vascular DCs is found in the arterial intima of healthy individuals and the rate Ziyuglycoside II of recurrence of DCs in arteries raises further during the course of atherosclerosis.6,14DCs can also occupy lipids and contribute to foam cell formation.15,16Although foam cells seem not to leave the progressive atherosclerotic lesion, monocyte-derived DCs are able to leave atherosclerotic lesions in regression.17Most monocyte-derived cells in atherosclerotic Ziyuglycoside II lesions express high levels of major histocompatibility complex class II (MHC-II), which is required for demonstration of peptide antigens to CD4+T cells. These mechanisms provide the fundamentals for activation of T cells in atherosclerotic lesions and recall reactions to both, model antigens and atherosclerosis antigens, which have been shown in mouse arteries using multiphoton imaging.18,19B cells found in the adventitia also express MHC-II.20,21In general, B cells can process soluble and membrane-associated antigen after their antigenic activation via the B cell receptor.In vivoimaging demonstrated CCR7-dependent migration of antigen-specific B cells22to the B cell T cell boundary in lymph nodes after antigen-encounter where these cells engaged in interactions with antigen-specific T cells for up to 60 min.23B cells are important antigen-presenting cells, but less able to present antigen to nave T cells than DCs.24The reconstitution ofmt/mice lacking B cells with B cells derived fromMhcII/mice resulted in an impaired antigen-specific T cell response, demonstrating that antigen presentation by B cells contributes to T cell activation.25The B cell specific deletion of MHC-II did not alter numbers of T cells, but reduced the frequency of activated CD4+and CD8+T cells inside a mouse model of lupus which was accompanied by amelioration of disease and improved kidney function.26Similarly, mice were shielded from experimental autoimmune encephalitis and displayed reduced Th1 and Th17 responses when B cells were devoid of MHC-II expression.27However, the part of antigen demonstration by B cells in atherosclerosis is unfamiliar. Antibodies specific for plaque-restricted antigens such as oxLDL were recognized in human being atherosclerotic plaques.13Further antigens recognized by antibodies in atherosclerosis are HSP60 and HSP65.28Lipid peroxidation-derived neoepitopes are found on the surface of oxidized (ox)LDL.29Spectratyping analysis of the T cell receptor (TCR) repertoire in atherosclerotic lesions exposed a limited variety of TCRs, which is the hallmark of an oligoclonal T cell response.30Unfortunately, TCR spectratyping allows no conclusions about the nature of the antigenic epitopes. The presence of oligoclonal T cells in atherosclerotic lesions shows the presence of an adaptive immune response mounted against atherosclerosis-relevant antigens. Such a response usually requires the migration of antigen showing cells (APC) such as DCs transporting plaque-derived.