普通楼 问答 (1).doc

【医学免疫学】 【神经生物学】自己整理的英文资料http:/www.cc98.org/dispbbs.asp?boardID=241 short Natural polypeptide; polysaccharidesSize 8-12aa(CD8+T);12-17aa(CD4+T) 5-15 aa; 5-7monosaccharidestype Linear determinant Conformational/linear determinationLocation Everywhere of Ag Surface of Ag3. the concepts of TD-Ag and TI-Ag and comparison between them TD-Ag: Thymus-dependent antigens are those that do not directly stimulate the production of antibody without the help of T cells. Proteins are thymus -dependent antigens. TI-Ag: Thymus-independent antigens are antigens which can directly stimulate the B cells to produce antibody without the requirement for T cell help. Polysaccharides are TI- antigens. TD-Ag TI-AgT cell help Necessary innecessaryEpitope B cell Virus reverse transcriptase proteinProtein, polyhexoseTCR binding site CD1、CD2 of TCR V CDR3 of TCR , chainMHC binding site (-helix)outside peptide-binding cleftMHC restriction - +T cell activity rate 1/20-1/5 1/105-1/106Character of immuno responseStimulate T cell directly Be presented by APC to T cells5. Functions of immunoglobulin:1) Recognition and binding to antigens, neutralization of toxins and microbes.2) Binding to Fc receptor of cells, mediating opsonization and antibody-dependent cellular cytotoxicity Medicating Type I hypersensitivity as well.3) Complement acitvation4) Passing through the placenta and mucosal.6. Three complement activation pathways (refer to the book and notes)7. The general properties of cytokine.1) Small proteins (MW: approx. 15-30 KD)3) Extremely potent, acting at 10-910-15M4) The production is transient and tightly regulated5) Acting through autocrine (e.g. IL-2), paracrine (e.g. IL-12) or endocrine (e.g. IL-1 and TNF-)6) Non-specific and non-MHC restricted7) The properties of cytokine actions: Pleiotropyone cytokine can acts on more than one cell type;Redundancymore than one cytokine have the same action （e.g. IL-2, IL-7, IL-15）Synergytwo or more cytokines cooperate to produce an effect that is different or greater than the combined effect of the two cytokines when functioning separately (e.g.IL-3 and CSF) Antagonismtwo or more cytokines work against each other (e.g. IL-4 and IFN-)8. Biologic functions of cytokines1) Anti-bacteria 2) Anti-virus 3) Mediation and regulation of adaptive immunity4) Stimulation of hemopoiesis 5) killing target cell, apoptosis 6) Angiogenesis9. Functions of CAM1) Serving as co-receptors and providing co-stimulatory signals in immune cells recognition and activation 2) Adhesion between leukocytes and vascular endothelial cells in inflammation3) Lymphocyte homing and recirculation10. Biological function of HLA1) Participate in the adaptive immune response serving as antigen presenting molecules(double recognition; autoimmunity and differentiation of T cells; disease susceptibility determination; genetic heterogeneity)2) Participate in the innate immunity serving as regulatory molecules(Classical MHC class III complement; HLA-E,G regulate activity of NK cells; inflammation related genes)11. Subtypes of B cellsubtype B1 cell B2 cellCD5 expression + -Mode of renewal Self-renewing Prodeued from bone marrowIsotypes secreted IgM>>IgG IgG>IgMRequirement of T cell help No YesSomatic hypermutation Low/none highMemory development Little/none Yes12. The process of B cell activation in response to TD-Ag1) B cells recognize TD-Aga. BCR directly recognizes B cell epitopes ; b. Ig/Igtransfer signal 1;c. Signaling pathways; d. effect of coreceptors ( CD21/19/81).2) Role of Th cells in humoral immune response to TD-Aga. Activation and migration of helper T cells; b. Presentation of Ags by B cells to Th cells;c. Th cell-mediated activation of B cell (co-stimulatory molecules)d. Th cells stimulate B cells to produce Abs of different heavy chain classes (isotypes);e. Affinity maturation in Ab responses (selection of high affinity B cells).13. General features of Ab responses in vivoPrimary immune responseLonger latent phase;Smaller peak response (lower Ab titer);Remaining in the serum at detectable Levels for much shorter periods;Lower average affinity;Usually IgM;Secondary immune responseShorter latent phase;Bigger peak response (higher Ab titer);Remaining in the serum at detectable Levels for much longer periods;Higher average affinity;Usually IgG.14. How do CD8+ T cells (CTL) directly kill target cells?1) Cytolysis (necrosis) - three stages: a. Contact phase: recognition of antigen in the context of MHC class I moleculesb. Secretory phase: release of cytolytic granules (perforin and granzymes)c. Lysis phase: osmotic death2) Induce cell apoptosisa. FasL-Fas: CTLs express FasL, interacting with Fas on target cells activation of caspase 8 apoptosisb. Granzymes caspase 10 apoptosis15. The general process of CD4+ T cell mediated immune response1) Antigen recognitiona. Ag is presented by APC b, Interaction between APC and T cell, including non specific binding of APC co-receptor-MHC; co-stimulatory molecules; T cell synapse or immunological synapse).2) Activation, proliferation and differentiation of T cells a. ·The first signal: TCR-antigen peptide-MHC complex (double recognition)·The second signal (co-stimulating signal): Interactions between co-stimulatory molecules on APC and corresponding receptors on T cells. E.g.CD28/CTLA-4 -B7; LFA-1-ICAM-1; CD2-LFA-3 ·Cytokines take part in T cell activation: IL-1,2,6,12 b. Signal transduction in T cell activationc. Proliferation and differentiation of T cells3）Effector functions of activated T cells