mechanisms of innate immunity & antigen presentation huan-yao lei, ph.d. department of...
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Mechanisms of Innate Immunity&
Antigen Presentation
Huan-Yao Lei, Ph.D.
Department of Microbiology & Immunology
College of Medicine
National Cheng Kung University
Summary of Chapter 6 Mechanisms of innate immunity • Innate immune responses do not depend on immune recognitio
n by lymphocytes • The body's responses to damage include inflammation, phagoc
ytosis, and clearance of debris and pathogens, and remodeling and regeneration of tissues.
• The phased arrival of leukocytes in inflammation depends on chemokines and adhesion molecules expressed on the endothelium.
• Leukocyte migration to lymphoid tissues is also controlled by chemokines.
• Plasma enzyme systems modulate inflammation and tissue remodeling.
• Pathogen-associated molecular patterns (PAMPs) are distinctive biological macromolecules that can be recognized by the innate immune system.
• Microbicidal proteins are part of the innate immune system.
Summary of Chapter 7 Antigen presentation • T cells recognize peptide fragments that have been processed and beco
me bound to major histocompatibility complex (MHC) class I or II molecules.
• MHC class I molecules associate with endogenously synthesized peptides, binding to peptides produced by degradation of the cells' internal molecules.
• MHC class II molecules bind to peptides produced following the breakdown of proteins that the cell has endocytosed.
• Cross-presentation allows APCs to acquire antigens from infected cells. • Co-stimulatory molecules are essential for T cell activation. • CD4 binds to MHC class II and CD8 to MHC class I molecules. • The highly ordered area of contact between the T cell and APC is an imm
unological synapse. • T cell activation induces enzyme cascades, leading to the production of in
terleukin-2 (IL-2) and the high-affinity IL-2 receptor on the T cell. • Antigen presentation affects the subsequent course of an immune respon
se.