【英⽂】医学免疫学-名解简答重点
【名解】Immunity: refers to all mechanisms used by the body as protection against environmental
substances that are foreign to the body.(to recognize and eliminate foreign substances)
【名解】Lymphocyte homing: the migration of lymphocytes from central immune organ to peripheral
immune organ
【名解】Lymphocyte recirulation：lymphocyte cirulation between blood lymph other tissues
【名解】Antigen: the substances that are recognized by TCR/BCR or antibody and induce a specific
immune response
【名解】Hapten（半抗原）：have the property of immunoreactivity but not immunogenicity .
【名解】epitope (antigenic determinant )：the portion of the antigen that binds specifically with the binding
site of an antibody or a receptor on a lymphocyte.
【名解】idiotypic Ag：The combined antigenic determinants (idiotopes) found on antibodies of an individual that are directed at a particular antigen; such antigenic determinants are found only in the variable region.
【名解】superantigen：antigens ，only need very low concentration ,can polyclonally activate some
subtypes of the T cells (up to 20%).
【名解】Adjuvants: A substance that when mixed with an immunogen, enhances the immune response against the immunogen.
【名解】Antigen: Globulin produced by plasma cells in response to antigen and binds specifically to
particular Ag.
【名解】Immunoglobulins (Ig)：The Igs are globulin which function as Abs or similar to Abs in chemical
structure.
【名解】idiotype,id:Variation in the V domain ,particularly in CDR, produces idiotype.
【名解】Major histocompatibility complex,MHC
A cluster of genes on chromosome 6 in humans, encoding major histocompatibility antigen which lead to rapid graft rejection.【名解】Cytokine (CK)：Cytokines are small soluble proteins that mediate immune and inflammatory reactions and are responsible for communications between leukocytes and other cells
【名解】Leukocyte differentiation antigen(LDA) :The cell surface markers which express or disappear on
the different leukocytes in the different stage of differentiation and activation.
【名解】CD (cluster of differentiation) : Cell surface molecules of leucocytes that are distinguishable with
monoclonal antibodies as an immunologic marker.
【名解】CAM: A group of proteins involved in adhesion of cell to cell or cell to extra-cellular matrix (ECM), such as ICAM-1, ICAM-2, ICAM-3, VCAM-1 and PECAM etc.
【名解】Integrin:Mediate adhesion of cell and extracellular matrix，Elementary structure: heterodimer of a, b chain
【名解】ADCC：NK cell FcR recgonize antibody Fc region binding with target cell,and directly kill the target cell.
【名解】opsonization:antibody such as IgG Fc region binding with neutrpilic cell or macrophage IgG FcR to increase phagocytosis.
【名解】APC:A variety of cells specialized in capturing、processing and present the antigen to the T lymphocytes, causing
either tolerance or immunity.
【名解】cross presention: APC can capturing\processing exogenous antigen and presenting to CD8 T cell by MHC1 pathway.
【名解】Positive selection:DP cells that bind, with moderate affinity, to MHC-Ag on thymic stroma cells
survive----MHC restriction MHC I----CD8+ T cells MHC II----CD4+ T cells
Negative selection:Cells that bind to MHC-Ag on thymic stroma cells (or auto-reactive T cells, ART) with high affinity will undergo apoptosis----Formation of central immune tolerance
【名解】ALLELIC EXCLUSION：Expression of a gene on one chromosome prevents expression of the allele on the second chromosome，Ensures only one specificty of Ab expressed per cell.
WHY:Allelic exclusion prevents unwanted responses;Allelic exclusion is needed for efficient clonal selection;Allelic exclusion is needed to prevent holes in the repertoire
【名解】Affinity maturation ：Affinity maturation is the process by which the affinity of Abs produced in response to a protein Ag increases with prolonged and repeated exposure to that Ag.
【名解】Treg: Down-regulation of immune response by inhibiting the activation and proliferation of CD4+ or CD8+ T cells.【名解】FoxP3+ :is the transcription factor that program the development of Tregs （IPEX综合症）【名解】Immune tolerance :is the process by which the Immune system does not attack an antigen. Is an active process which is different from immunodeficiency or immunosuppression.
【名解】AICD:Activation-induced Cell Death,recognition and deletion of T lymphocytes that have been
induced to proliferate by receptor-mediated activation, preventing their overgrowth.
【名解】AIRE(autoimmune regulator): transcription factor that enables ectopic expression in the thymus of
genes usually considered tissue-specific.
【名解】Immuno-labeling techniques：Specific Abs (or Ags ) labelled with fluorescein, enzymes or radioisotopes are used as probes for the detection of Ags (or Abs).
【名解】ELASA
【简答】Functions of V regions：Recognition and binding to antigen by HVR (CDR)
- neutralization of toxins (e.g. diphtheria,
tetanus);
- immobilization of microorganisms;
- neutralization of viral activity
Function of C regions (Fc portion)
1. Activation of complement: IgM, IgG
Ab( IgM、IgG )+Ag--- C1q----补体经典途径
IgG4、IgA和IgE的凝聚物----补体旁路途径
2. Binding to Fc receptor of cells
Opsonization: enhancement of Ag uptake by macrophages (M?)
Antibody-dependent cell-mediated cytotoxicity (ADCC): NK cells.
Participation in type I hypersensitivity: IgE
3. Passage through the placenta (IgG, CH2)
and mucosa (sIgA)
【简答】
Biologic function of complement system
www.doczj/doc/60485b6e27d3240c8447ef4c.html plement mediates anti-infection immunity
(1) Lysis of cell or microorganisms
(2) opsonization C3b, C4b, iC3b cell: phagocyte enhance phagocytosis
(3) inflammation symptoms: redness, swelling, heat and pain
inflammation mediators: C5a, C3a, C4a ( anaphylatoxins) C5a (chemotaxis)
2. Complement maintains homeostasis
clearance of IC: C3b
elimination of apoptosis cells C1q, C3b, iC3b
3. Complement mediates adaptive immunity
4. Complement interacts with other enzyme systems
【简答】MHC molecules difference
1) HLA class I molecules
Genes: A, B, C
Distribution: every nucleated cell
Structure: α chain (45k) β2m (12kD) chromosome 15
peptide-binding cleft: α1+α2
CD8 binding: α3
Function: recognize and present endogenous Ags to CD8+ T cells
2) HLA class II molecules
Genes: DR, DQ, DP
Distribution: APC (B, DC, MΦ) thymic epithelial cell, activated T cell
Structure: α chain (35kD)
β chain (28kD)
peptide-binding cleft: α1+β1
CD4 binding: β2
Function: recognize and present the exogenous Ags to CD4+ T cells
【简答】Biological function of MHC
1、Participate in the adaptive immune response serving as antigen presenting molecules
(1)T cells recognize both the antigenic peptide and MHC molecules by TCR (double recognition)
(2)MHC molecules can present both autoantigens and allogenic MHC molecules
(3)MHC molecules participate in selection and differentiation of T cells in the thymus.
(4)MHC is the crucial determinant of disease susceptibility in different individuals；
(5) MHC contributes to the genetic heterogeneity of the population
2. Participate in the innate immunity serving as regulatory molecules
(1)Classical MHC class III genes encode complement, hereby participating in complement reaction and the pathogenesis of some immune diseases.
(2)Non-classical HLA class I molecules (HLA-E, G) regulate the activity of NK cells.
(3)Inflammation related genes initiate and control inflammation. They also play a role in stress. (such as HSP).
【简答】General properties of CKs
Small proteins (MW: approx. 8-30 KD)
Extremely potent, acting at 10-9~10-15M
The production is transient and tightly regulated
Autocrine, paracrine or endocrine
Cytokine actions: Pleiotropy, Redundancy, Synergy and Antagonism
【简答】What are the differences between immature DC and mature DC
Inmature DC
Phenotype: high expression of receptors related to phagocytosis (FcR, CR, mannose receptor, DC-sign); low expression of CD54, CD40, CD80; CD86 and MHC II, CD14-
Function: 1) strong capacity to ingest and process Ags, but weak ability to present Ags
2) induction of immune tolerance
3) sensing of infectious agents by TLR (pattern recognition receptors)
Mature DC
Phenotype: low expression of receptors related to phagocytosis (FcR, CR, mannose receptor); high expression of CD54, CD40, CD80, CD86 and MHC II; CD83+ and CD25+
Function: weak ability to capture and process Ags, powerful ability to present Ags
【简答】Effector functions of activated T cells（重点）proliferation
1) CD4+ T cells
Th1: secrete IFN-γ, etc.
express CD40L
express FasL, kill Fas+ target cells
effect on lymphocytes: IL-2
effect on neutrophil: TNF-α,β
Th2: promote B cell growth and Ig production
mediate hypersensitivity
Th17: IL-17,IL-8,TNF-α: enhance leukocyte recruitment and inflammation
2). Effector functions of CD8+ T cells
Cytotoxicity:
kill target cells
a. necrosis: perforin and granzyme
b. apoptosis: granzyme, FasL
【简答】fuction of b cell
1. Production of antibody
Abs prevent microorganism from entry into cells and eliminate microorganisms by opsonization causing phagocytosis, complement activation and toxin neutralization.
2. Ag presentation to T cells
3. Immune regulation
Secretion of cytokines (TNF, IFN, IL-12) →Mφ, DC, NK, B cell.
Co-stimulation of T cells→T cell proliferation
【简答】General features of Ab responses in vivo（体液免疫应答特点）
Primary immune response
- longer latent phase;
- smaller peak response (lower Ab titer); - remaining in the serum at detectable
levels for much shorter periods;
- lower average affinity;
- usually IgM;
【——】
1). Activating receptor:
ITAM (immunoreceptor
tyrosine-based activation motif)
Motifs：YxxL/V
Recruit : kinases, adaptor proteins Induce activation signal
【简答】１型超敏反应机制及常见病secondary antigenic challenge
- shorter latent phase;
- bigger peak response (higher Ab titer); - remaining in the serum at detectable
levels for much longer periods;
- higher average affinity;
- usually IgG.
2). Inhibitory receptor:
ITIM (immunoreceptor
tyrosine-based inhibitory motif)
Motifs：I/Vx YxxL
Recruit Protein phosphatases Transduce inhibitory singnal