University:
Rutgers University Newark
Course:
CHEM 335 | Organic Chemistry
Academic year:

2024
Views:

422

Pages:

69
Author:

Mahitab S.

Stranford Owen Punt Jones Kuby Immunology EIGHTH EDITION Lecture Slides CHAPTER 4 Innate Immunity Macan Learring 2023 Innate Immunity OVERVIEW FIGURE Fig. 4-1 Macmillan Learning 2023 AMPs Epithelial layers produce hundreds of protective antimicrobial proteins and peptides (AMPs). One AMP, lysozyme, was discovered in 1922 by Sir Alexander Fleming. Lysozyme cleaves bonds between NAM and NAG sugars in the cell wall of bacteria, leading to bacterial death. More than 22,000 AMPs have been identified. AMP Sources and Functions AMPs are found in tears, saliva, milk, intestinal epithelia, and the skin. AMPs have broad antimicrobial activity, including: finding and sequestering iron to prevent bacterial growth, disrupting microbial membranes, leading to cell death, preventing bacterial binding, antifungal action, and antiviral action. ©Macmillan Learning 2023 Other Sources and Functions of AMPs AMPs can be derived from commensal bacteria. Commensal microbes synthesize AMPs as part of their competitive strategy. Examples include penicillin, polymyxin B, vancomycin, and phenol-s oluble modulins (PSMs). AMPs are multifactorial in nature as they can have other functions including regulation of innate immune cells and wound healing. Macmillan Learning 2023 PRRS, PAMPs, and DAMPs Innate immune cells recognize pattern-recognition receptors (PRRs). PRRs recognize pathogen-associated molecular patterns (PAMPs), which are microbially derived molecules shared by many different strains of bacteria viruses, parasites, or fungi. Some PRRs recognize dead or damaged host cells expressing DAMPs (damage-associated molecular patterns). PRRs are found on a wide variety of cell types. Macmillan Learning 2023 Myeloid Cells in Innate Immunity Cells of the myeloid lineage are often first to respond to pathogen invasion. They: attempt to destroy the invading pathogen, alert other immune cells to the presence of the invading pathogen using chemical mediators, and include neutrophils, eosinophils, basophils, monocytes, dendritic cells, macrophages, and mast cells. Macmillan Learning 2023 Neutrophils Neutrophils are the most abundant granulocytic myeloid cells in the blood. They: express a broad array of PRRS, respond to chemoattractant molecules released when pathogens invade, can directly destroy pathogens via phagocytosis or neutrophil NETS (webs of chromatin and DNA which trap pathogens), and secrete proteins to enhance the immune response.