超敏反应-2015-英五班
《超敏反应-2015-英五班》由会员分享,可在线阅读,更多相关《超敏反应-2015-英五班(59页珍藏版)》请在装配图网上搜索。
1、Hypersensitivity,Guangjie Chen Dept. of Immunology and Microbiology 2015,The Big Bang Theory,Hypersensitivity (allergy) Hypersensitivity is an inappropriate immune response, which is heightened reactivity to an antigen, such response lead to tissue damage, immunopathology. The various hypersensitivi
2、ty states were classified into I through IV types by Gell and Coombs. Type I, II and III reactions are mediated by antibodies, whereas type IV reactions are mediated by T cells.,I. Type I hypersensitivity(anaphylaxis),The major components (1)allergen drug, chemical inhalant allergen :pollens、Dust mi
3、te food allergens:nuts, seafood,Plane tree,Castor-oil plant,Dust mite,(2)Ig E antibody and IgE receptor,Levels of Ig E and atopic diseases,IgE and IgE receptors IgE-Fc RI (ITAM),Antigen indirectly cross links FcR on mast cells or basophils?,(3)Cells,Mast cell/ basophils: FcRI eosinophils:express FcR
4、I after stimulation of IL-5,MCP-3 Cross link Degranulation Release of preformed mediators and newly produced mediators,Light photomicrograph and Electron micrograph of Mast cell activation,Abul K. abbas et al. Cellular and Molecular Immunology, 7th edition, Elsevier Saunders,2. Mechanism of Type I h
5、ypersensitivity,Sensitization phase Excitation phase Effector phase,1. Sensitization phase allergen enter the body stimulate Ag-specific B cells differentiated to plasma cells production of IgE Bind with high-affinity FcRI which expressed by mast cells and basophils,Activated mast cell or activated
6、basophil,2. Excitation phase The same allergen enter the body againbind to IgE which was bound to mast cells and/or basophils, cross link of FcRI induction the degranuation of mast cells and basophils, release biological active mediators,Biological active mediators : 1. preformed mediators:histamine
7、, eosinophil chemotactic factor (ECF), kininogenase , tryptase 2. newly produced mediators: leukotrienes, prostaglandin D2, platelet activating factor, cytokines,3. Effector phase Immediate phaseseveral seconds after contact of allergen, can persist several hours, caused by histamine Late phase6-12h
8、 after contact of allergen, can persist several days,Distribution and function of histamine,type of tissue effect clinical receptor contraction relaxation manifestation H1 airway smooth muscles + asthma alimentary tract muscles + diarrhea, vomit vascular endothelial cell + edema H2 vascular smooth m
9、uscle + shock,Abul K. abbas et al. Cellular and Molecular Immunology, 7th edition, Elsevier Saunders,Biologic effects of mediators of immediate hypersenitivity,Different substances cross link FcR,3. Ig E mediated allerigic diseases (type I hypersensitivity) (1) anaphylactic shock caused by drugs (2)
10、 anaphylactic shock caused by animal serum(TAT) (3) hypersensitivity reaction in respiratory tract allerigic rhinitis, bronchial asthma,(5) hypersensitivity reaction in skin,(4) hypersensitivity reaction in gastrointestinal tract seafood, milk,Bee sting,urticaria,Allergic reaction in response to tes
11、t antigens can be divided into an immediate response and a late-phase response,Asthmatic response in the lungs with narrowing of the airways,PFER: peak expiratory flow rate,4. Principals of prevention and therapy for type I hypersensitivity,(1) Skin test,(2)Desensitization therapy Heteroserum desens
12、itization:small dose, repeated injection, 30-50 min interval(TAT) allergic to penicillin is forbidden to use this method Specific allergen desensitization : small dose, repeated injection, long time interval, inducing IgG production,decreasing IgE production,(3) Drug therapy,Hygiene hypothesis,The r
13、emarkable increase in asthma prevalence that has occurred over the last two decades is thought to be caused by changes in the environment due to improved hygiene and fewer childhood infection.,II. Type II hypersensitivity (cytotoxic hypersensitivity),Mechanism of type II hypersensitivity (1)Ag cell
14、surface Ag Ab(IgG),(2)specific Ab, complement and effector cell ADCC、CDC、phagocytosis,2. Common diseases caused by type II hypersensitivity (1)transfusion reactions,Blood typeAgAb/serum A Aanti-B B Banti-A AB A、Bnone O Hanti-A、anti-B,(2)Hemolytic disease of the newborn induced by Rhesus incompatibil
15、ity,(3)Autoimmune hemolytic anemia infection: changed epitope drug: hapten,(4)Graves disease (special type),III. Type III hypersensitivity (soluble immune complex),Mechanism of type III hypersensitivity large immune complexes-phagocytosis small immune complexes-kidney filtration medieum immune compl
16、exes-exist for a long time, deposit in small vessels,2. Common diseases caused by type III hypersensitivity,(1)local immune complex-mediated diseases 1903 Arthus Arthus reaction, arthus-like reaction,Inhaled antigen induced type III hypersensitivity,Diseases,antigen,hay dust,farmers lung,fur protein
17、,furriers lung,pigeon droppings,pigeon-fanciers disease,Penicillium casei spores,cheese washers disease,Hidden mold spores,maple bark strippers disease,(2)Systemic immune complex-mediated diseases Serum sickness Poststreptococcal glomerulonephritis Rheumatoid arthritis Systemic lupus erythematosus,S
18、erum sickness,IV. Type IV hypersensitivity (cell mediated, delayed type),2. Common diseases caused by type IV hypersensitivity,(1)Infective hypersensitivity Leprosy,Tuberculosis,Abul K. abbas et al. Cellular and Molecular Immunology, 7th edition, Elsevier Saunders,Contact dermatitis caused by ivy pr
19、ison,(2) Contact dermatitis,Abul K. abbas et al. Cellular and Molecular Immunology, 7th edition, Elsevier Saunders,Example: purified protein derivative (PPD), a protein Ag of mycobacterium tuberculosis, elicits a DTH reaction, called tuberculin reaction. Positive skin test response is clinical indic
20、ator for evidence of previous or active tuberculosis infection.,Key points: Definition of hypersensitivity reactions Mechanism of hypersensitivity reaction of four types Related diseases,Essay Discuss ONE of the following statements,Hygiene hypothesis: The remarkable increase in asthma prevalence th
21、at has occurred over the last two decades is thought to be caused by changes in the environment due to improved hygiene and fewer childhood infection.,Allergic diseases, including rhinitis and asthma, are chronic inflammatory disorders with a prevailing Th2 immune response. The inhalation of allerge
22、ns leads to hyperreactivity, recruitment of eosinophils, mast cells, and lymphocytes in the upper and lower airways triggering the inflammatory cascade and generating local and systemic inflammatory responses. Th17 cells and IL-17A play a role in the development and progression of allergic diseases. Pharmacological treatment might restore the balance between Th17 and Treg promoting the resolution of inflammation in airway diseases .,Whats the role of Th17 and IL-17A in asthma and rhinitis ?,
- 温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 装配图网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。