tailieunhanh - Introduction to Medical Immunology - part 5

Đặc điểm số trong các hình thức thường trú máu ngoại vi trong mô thực bào Fc Nonimmunological thụ C3b thụ thể chế phẩm enzim dùng hạt enzyme Khả năng diệt khuẩn để tạo ra superoxide và tổng hợp H2O2 và phát hành của leukotrienes Tổng hợp và phát hành của prostaglandinphát hành của PAF phát hành | Page 318 Table Comparison of the Characteristics of PMN Leukocytes and Monocytes Macrophages Characteristic PMN leukocytes Monocyte macrophage Numbers in peripheral blood 3 - 6x103 ựL 285-500 mL Resident forms in tissues - macrophage Nonimmunological phagocytosis Fc receptors FcỵRII III FcgRI II III C3b receptors Enzymatic granules Bactericidal enzymes Ability to generate superoxide and H2O2 Synthesis and release of leukotrienes B4 B4 C4 D4 Synthesis and release of prostaglandins - Release of PAF Release of interleukins Response to nonimmunological chemotactic factors - Response to C5a C3a - Response to lymphokines IL-8 IFN-g Antigen processing - Expression of HLA class II antigens - Phagocytosis-independent enzyme release - a. Among bacterial products formyl-methionyl peptides such as f-methionine-leucine-phenylalanine f-met-leu-phe are extremely potent chemotactic agents. b. Tissue damage may result in the activation of the plasmin system that may in turn initiate complement activation with generation of C5a another extremely potent chemotactic agent. c. Many microorganisms can probably generate C5a by activation of the complement system through the alternative pathway. d. After an inflammatory process has been established proteases released by activated neutrophils and macrophages can also split C5 and the same cells may release leukotriene B4 another potent chemotactic factor attracting more neutrophils to the site. e. Chemokines such as IL-8 monocyte chemotactic protein-1 and RANTES are also chemotactic for neutrophils and monocytes. 3. After receiving a chemotactic stimulus leukocytes undergo changes in the cell membrane which is smooth in the resting cell and becomes ruffled after the cell receives the chemotactic signal. The activated PMN has a marked increase in cell adhesiveness associated with increased expression of adherence molecules namely integrins of the CD11 CD18 complex which includes a. CD11a the a chain of LFA leukocyte function antigen -1