The CD40 ligand. At the center of the immune universe?
For several years, the primary function of CD40 ligand (CD40L) has been believed to be in regulation of contact-dependent, CD40-CD40L-mediated signals between B- and T-cells, which are essential for the regulation of thymus-dependent (TD) humoral immune responses. Recently, a flurry of reports indicate that CD40 is expressed by variety of cell types other than B-cells that include dendritic cells, follicular dendritic cells, monocytes, macrophages, fibroblasts, and endothelial cells. These studies show that CD40-CD40L interactions are important in inflammatory process. For the past few years, through the availability of CD40L-knockout mice, new data have emerged to support the belief that CD40L has many more functions than its role in TD humoral immunity. CD40L-deficient mice have provided significant information towards our understanding of the in vivo role of CD40L. The current picture that emerges indicates that CD40-CD40L interactions mediate many cell-mediated immune responses and T-cell-mediated effector functions that are required for proper functioning of the host defense system. This article focuses on the in vivo role of the CD40L in regulation of cell-mediated effector functions.
Grewal
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Howard Hughes Medical Institute, Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA.
Flavell
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D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000502:physiology; D015551:Autoimmunity / Q000276:immunology / Q000502:physiology; D019013:CD40 Antigens / Q000378:metabolism*; D023201:CD40 Ligand; D016207:Cytokines / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007239:Infections / Q000276:immunology / Q000473:pathology; D008024:Ligands; D008264:Macrophages / Q000276:immunology / Q000502:physiology; D008562:Membrane Glycoproteins; D009000:Monocytes / Q000276:immunology / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology
D019013:CD40 Antigens; D016207:Cytokines; D008024:Ligands; D008562:Membrane Glycoproteins; D023201:CD40 Ligand