Cardiovascular disease is the leading cause of mortality worldwide, and atherosclerosis the principal factor underlying cardiovascular events. Atherosclerosis is a chronic inflammatory disease characterized by endothelial dysfunction, intimal lipid deposition, smooth muscle cell proliferation, cell apoptosis and necrosis, and local and systemic inflammation, involving key contributions to from innate and adaptive immunity. The balance between proatherogenic inflammatory and atheroprotective anti-inflammatory responses is modulated by a complex network of interactions among vascular components and immune cells, including monocytes, macrophages, dendritic cells, and T, B, and foam cells; these interactions modulate the further progression and stability of the atherosclerotic lesion. In this review, we take a global perspective on existing knowledge about the pathogenesis of immune responses in the atherosclerotic microenvironment and the interplay between the major innate and adaptive immune factors in atherosclerosis. Studies such as this are the basis for the development of new therapies against atherosclerosis. Int. J. Mol. Sci. 2019, 20, 5293 2 of 48 cytotoxic T lymphocytes at the interface between innate and adaptive immunity. Abundant evidence indicates that innate and adaptive immunity both play important roles in the onset and progression of atherosclerosis [1][2][3]. For example, Csf1 −/− mice, which lack macrophage colony stimulating factor (M-CSF, also known as CSF1) are less prone to developing atherosclerosis [4]. Moreover, mice lacking B and T cells (Rag1 −/− or Rag2 −/− mice lacking recombination-activating genes 1 or 2 or mice carrying the severe combined immunodeficiency (SCID) mutation) are resistant to atherosclerosis in the presence of mild hypercholesterolemia [5][6][7][8][9][10]. Int. J. Mol. Sci. 2019, 20, 5293 2 of 46 cells are cytotoxic T lymphocytes at the interface between innate and adaptive immunity. Abundant evidence indicates that innate and adaptive immunity both play important roles in the onset and progression of atherosclerosis [1][2][3]. For example, Csf1 −/− mice, which lack macrophage colony stimulating factor (M-CSF, also known as CSF1) are less prone to developing atherosclerosis [4]. Moreover, mice lacking B and T cells (Rag1 −/− or Rag2 −/− mice lacking recombination-activating genes 1 or 2 or mice carrying the severe combined immunodeficiency (SCID) mutation) are resistant to atherosclerosis in the presence of mild hypercholesterolemia [5-10].
Atherosclerosis's PathophysiologyAtherosclerosis is a chronic inflammatory disease of large and medium-sized arteries [20], characterized by endothelial dysfunction and the accumulation of low-density lipoproteins (LDL), immune cells, and necrotic debris in the subendothelial space, resulting in the formation of an atherosclerotic plaque [21][22][23][24]. LDL deposition is more likely in regions with turbulent flow and low shear stress [25] sensed by the vascular endothelium [26]. Turbulent flow modulates endothelial transcrip...