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1、青岛大学基础医学院医学免疫学课件 chapter11,青岛大学基础医学院医学免疫学课件 chapter11,基础医学院医学免疫学课件-chapter11,基础医学院医学免疫学课件-chapter11,1、mIgStructure：mIg consist of a basic unit of four polypeptide chains,two identical H chains and two identical L chains.Intracellular region is very short. immature B cells express mIgM， mature B cell
2、s express mIgM and mIgD simultaneously，plasma cells dont express Ig. Function：specific binding antigen,1、mIg,2、Ig/Ig Structure ： Ig（CD79a）and Ig （CD79b）belong to Ig gene surperfamily，consist of extracellular region，transmembrane region and cytoplasma region，Ig and Ig held together by disulfide bond
3、to form heterogenous dimer,then form BCR-Ig/Ig complex with BCR. Function：1、 transducing antigen-binding signal to B cell2、 transferring Ig from inner of cell to outer of cell,2、Ig/Ig,Distribution of BCR complex：mature B cell and immature B cellpre-B receptor consists of chain、substitute L chain and
4、 Ig/Ig ， pre-B receptor expressing on the surface of pro-B cell，is really important for B cell development in bone marrow.,Distribution of BCR complex：,基础医学院医学免疫学课件-chapter11,1,2,13,14,15,16,17,18,19,20,3,4,5,6,7,8,9,11,12,10,Lymphocytes have unique, clonally distributed antigen receptors,Antibodies
5、,B cells,121314151617181920345678911121,二、co-receptor,1、CD19/CD21/CD81/CD225Structure and Distribution ：The co-receptor on the surface of B cell is composed of CD19、CD21 and CD81/CD225（Leu-13）with non-covalent bond.ligand：C3dg , C3d, iC3bfunction：enhance the sensitivity of B cell to antigen stimulus
6、,二、co-receptor1、CD19/CD21/CD81/,基础医学院医学免疫学课件-chapter11,2、CD72Structure: Belongs to C-type lectin superfamily, is a 45kDa II-type transmembranous protein. Distribution:Constituent expression on every stage B cells except plasma cells. Contain 2 ITIMLigand：CD100,expressed on most hemocytoblast includi
7、ng B and T cells. CD100 interacting with CD72 can eliminate the inhibition by CD72，enhancing the effect of signal 1 . Function:When BCRs cross link, it can inhibit the stimulation of signal 1.,2、CD72,三、 co-stimulation molecules,1、CD40Structure: Belonging to TNFRSFDistribution： Constituent expression
8、 on mature B cellLigand：CD40L/CD154（ expression on activated T cells）Function：play an very important role in B cell differentiation and mature,三、 co-stimulation molecules1、C,2、CD80/86Structure: another name B7.1（CD80）/B7.2（CD86）， is single chain transmembrane glycoproteinDistribution：expression on a
9、ctived B cellsLigand：CD28、 CTLA-1（ expression on activated T cells ）Function：offer co-stimulating signal for T cell activation（because B cell is APC ）,2、CD80/86,基础医学院医学免疫学课件-chapter11,3、CD27Structure： Belonging to TNFRSF。Distribution： CD27（ activated B cells ）Ligand：CD70（ CD154+CD70+T cell）Function：
10、 Play a role in B cell differentiating to plasma cells,B,T,CD27CD70,CD70CD27,3、CD27BTCD27CD70,4、CD70Expression： activated B cellsLigand ： CD27 （CD45RA+CD4+ T cell）Function： Play a role in CD45RA+CD4+ T cells differentiating to regulatory T cells to inhibit the production of Ab. 5、othersICAM-1、LFA-1
11、etc.,4、CD70,四、 membrane-binding molecules of mitogen LPS receptor、PWM receptor五、other membrane molecules1、CD20：Distribution：expressed on every stage B cells except for plasma cells.Function：Regulate the proliferation and differentiation of B cells .,四、 membrane-binding molecules,2、CD22：Distribution：
12、 Expresses on B cells specially， and doesnt express on plasma cellLigand ：CD45RO、CD75 （唾液酸聚糖分子）Function：Binding CD45RO、CD75，mediate interaction on B-monocyte、B-T、B-B .3、CD32：Fc R II-B,2、CD22：,基础医学院医学免疫学课件-chapter11,Section 2 Subgroup of B cells,B-1 cell：CD5+ ，appears on individual development forepa
13、rt ，locate in peritoneum、pleura etc. innate immunity，play a role in mucous membrane immunityAntigen of stimulating ： LPS（ lipid polysaccharides ）Production antibody：IgMPolyreactivity ： B-1 cell antigen receptor and antibody can bond all kinds of antigen epitope using relatively low affinity,Section
14、2 Subgroup of B cells,Functions of B-1 cells：1、anti-microbe infection by producing anti bacteria antibody. 2、clearing degenerative self-antigen by producing poly-reactive autoantibody3、inducing autoimmune disease by producing pathogenic autoantibody.,Functions of B-1 cells：,B-2 cell： ordinary B cell
15、，CD5-，Contain tow subsets of MZ（marginal zone）and follicular MZ B cell is the first line of defenceFO B cell participates later antibody response of T cell dependentThe most B cell in Peyers patches （PP）in GALT is B-2 celladaptive immunity,B-2 cell： ordinary B cell，CD5-,Similarities and differences
16、of B-1 cell and B-2 cell,Similarities and differences o,characterB-1 B-2CD5+-First tim,Section 3 function of B cell,（一）produce antibodies1、 neutralization: bacteria toxin ,pathogen2、 opsonization：Ab、complement3、antibody-dependent cell-mediated cytotoxicity（ADCC）4、 activate Complement : opsonization
17、and lyse microbe,Section 3 function of B cell,基础医学院医学免疫学课件-chapter11,基础医学院医学免疫学课件-chapter11,基础医学院医学免疫学课件-chapter11,（二）antigen presenting ： activated B cells presenting soluble Ag,（二）antigen presenting ：,（三）immunoregulation ：positive and negative regulationActivate M & FDC ：IFN-、TNF、IL-6、GM-CSFinhibit M & FDC ：IL-4、IL-10、TGF-；Activate NK: IL-12、IFN-、IFN-、 IL-2 ， inhibit NK: TGF- ；Induce inflammatory cells refresh by chemotaxis：IL-8、G-CSF、GM-CSF；Co-stimulate T proliferation：IL-1 、IL-1 、 TNF、GM-CSF,（三）immunoregulation ：,
