T-Cell Immunity in Acute Coronary Syndromes Cornelia M. Weyand, MD, Jörg J. Goronzy, MD, Giovanna Liuzzo, MD, Stephen L. Kopecky, MD, David R. Holmes, MD, Robert L. Frye, MD  Mayo Clinic Proceedings  Volume 76, Issue 10, Pages 1011-1020 (October 2001) DOI: 10.4065/76.10.1011 Copyright © 2001 Mayo Foundation for Medical Education and Research Terms and Conditions

Figure 1 Interface between the innate and adaptive immune responses. Cells of the innate immune system, such as monocytes/macrophages, use antigen-nonspecific receptors to recognize bacterial products and to bind complement and immuno-complexes. They phagocytose particulate material, process the proteins into peptides, and present these processed peptides, which have been embedded in HLA molecules, on the cell surface. Cells of the adaptive immune system, T cells, then recognize HLA-peptide complexes through their antigen-specific receptors. Triggering of the antigen receptor on the T cell, in conjunction with other costimulatory signals, initiates a cascade of events that leads to cytokine production, clonal expansion of the T cell, and generation of memory T cells. APC = antigen-presenting cell; MHC = major histocompatibility complex; TCR = T-cell receptor. Mayo Clinic Proceedings 2001 76, 1011-1020DOI: (10.4065/76.10.1011) Copyright © 2001 Mayo Foundation for Medical Education and Research Terms and Conditions

Figure 2 Rupture-prone atherosclerotic plaque-a lesion infiltrated by T (T) cells and macrophages (M). An atherosclerotic plaque at high risk of rupture has several characteristics: (1) T cells recruited to the shoulder region, (2) macrophages clustered around the T cells, (3) thin fibrous cap, (4) lipid-rich core, (5) newly formed intrawall capillaries, and (6) lymphocyte and mast cell infiltration into the adventitia. Mayo Clinic Proceedings 2001 76, 1011-1020DOI: (10.4065/76.10.1011) Copyright © 2001 Mayo Foundation for Medical Education and Research Terms and Conditions

Figure 3 CD4+ natural killer (NK)-T cells-a cell hybrid combining characteristics of the innate and adaptive immune systems. CD4+ NK-T cells have T-cell receptor dimers, which provide them with the ability to recognize antigen. They have lost expression of CD28, a critical costimulatory molecule, and have acquired expression of the NK receptors CD158 and CD161. In contrast to classic helper T cells and in analogy to NK cells, NK-T cells have cytotoxic capability and can lyse target cells. INF = interferon; IL = interleukin. Mayo Clinic Proceedings 2001 76, 1011-1020DOI: (10.4065/76.10.1011) Copyright © 2001 Mayo Foundation for Medical Education and Research Terms and Conditions