免疫学历年试题 名词解释部分 整理人：apredatorTD-Ag
: thymus-dependent antigens, areantigens that can stimulate B cells to produce antibody only with the help of Tcells.
Most TD-Ags are proteins, and have moredifferent kinds of epitopes but less numbers for each kind. It can induce bothCMI and HI, and have immune memory. TI-Ag
: thymus-independent antigens, areantigens that can stimulate B cells to produce antibodies without the help of Tcells.
MostTI-Ags are polysaccharides and lipids, and have repeated epitopes, and can onlyinduce HI, and don’t have immune memory.
opsonization:Opsonization can be induced by antibody or complement.
IgGand IgM can combine with antigens and Fc fragment of IgG can combine with theFcR of macrophages and promotes its phagocytosis. C3b and C4b can combine withthe CR1 of macrophage and promotes phagocytosis,
sequentialepitope: Epitopes formed by adjacent amino acid residues are called sequentialepitopes. They are usually recognized by T cells and can appear at any sites ofthe antigen.
HLA:human leukocyte antigen, HLA are cell surface molecules expressed ordisappeared during different development, differentiation and maturationphases, as well as the activation phase.\
idiotypedeterminant: Igs produced by different B cells possess unique structurerespectively in the hypervariable region(HVR), these unique structures of Igsare called idiotype determinants. adhesion molecules
: are cell surfaceglycoproteins that mediate the binding of one cell to other cells or toextracellular matrix proteins. It plays an important role in the immuneresponse and is dependent on the binding of receptor to ligand. GVHD
: graft-versus-host-disease, is adisease caused by GVHR, in which the mature lymphocytes(mostly T lymphocytes) inthe graft cause damage to the host. It usually happens in the thymus and bonemarrow transplantation.
centraltolerance: Immature immune cells in the central immune organs encounter selfantigens and form tolerance to self antigens.
crosspresentation: Endogenous antigens are presented by MHC-II molecules andrecognized by CD4+T cells. Exogenous antigens are presented by MHC-I moleculesand recognized by CD8+ T cells. isotype switching
: Activated B cells expressIgM firstly, and then gradually change its Ab isotype into IgG and IgA. Therearranged VDJ genes combine with a downstream C region genes and theintervening DNA is deleted.
immunetolerance: Unresponsiveness to an antigen which is induced by former exposureto that antigen. Normal responsiveness to other antigens.
conformationaldeterminants: Epitopes formed by amino acid residues that are not in a sequencebut become spatially juxtaposed when folded into a protein. It is usuallyrecognized by B cells.
heterophilicantigen: are common antigens that are shared by different species. Commonantigens are different antigens that have the same or similar epitopes. CDR
: complementarity determining region,they are some of the sequences formed in the antibody complementary to thethree dimensional structure of the bound antigen.
PRR:pattern recognition receptors. Receptors on the innate immune cells thatcombine with the conserved structures of the microbes(PAMP). APC
: A group of immune cells which cancapture exogenous and endogenous antigens, process them in the cell and thenpresent them with MHC II and I molecules for recognition of CD4+ or CD8+ Tcells, which plays an important role in immune response.
lymphocyterecirculation: Lymphocytes are continuously moving through the blood and lymphaticsbetween different lymphoid organs, and when activated, to specific inflammatorytissues. immunologicsynapse
:The highly ordered structures formed between APC and T lymphocytes, in which alarge cluster of TCR and MHC-peptide complexes are surrounded by a ring of celladhesion molecules.
Tcell epitope: Antigenic determinants recognized by T cells are called T cellepitope. They are mostly peptides with 8-23 amino acids and can appear anywherein the antigen, most of them are linear epitopes, and need MHC and APCpresentation to activate B cells.
Bcell epitope: Antigenic determinants recognized by B cells are called B cellepitope. They are mostly polysaccharides and lipids or peptides with 5-15 aminoacid residues, and most of them are conformational epitopes on the surface ofthe antigen.
CK:CK are low molecular weight proteins produced and secreted by many differentcell types, and play an important part in immune and inflammatory response,
ADCC:antigen-dependent cell-mediated cytotoxicity, The Fc fragment of the antibodyattached to the antigen can combine with the FcR on the NK cell and macrophageand induce the release of cytotoxic substances like perforin and granzyme.
TSA:tumor-specific antigen, antigens that are only expressed on tumor cells but noton normal cells.
lymphocytehoming: The directed migration of circulating lymphocytes into particulartissue sites It is regulated by the selective expression of endothelial adhesionmolecules and chemokines and is realized by the interaction of the addressinand lymphocyte homing receptor.
PAMP:pathogen-associated molecular pattern, the highly conserved structures sharedby particular groups of microbial pathogens, which can be recognized by theinnate immune cells, like LPS, LTA, etc.
idiotype:Different Igs produced by different B lymphocytes possess unique structuresrespectively in the hypervariable regions, these unique structures of the Igsare called isotypes.
MHC:major histocompatibility complex, are a group of linked genes in some of thechromosome in human and other mammals that encode for MHS and is associatedwith immune response, immune regulation, cell-cell adhesion and allograftrejection.
immuneignorance: is a form of lymphocyte unresponsiveness in which the self antigensare ignored by the immune system, but the lymphocytes specific for that antigenremain viable and functional.
AICD:activation-induced cell death.
T: Repeated challenge of the lymphocytes withconsistent antigens results in the death of that cell, by a process ofapoptosis.
B:B lymphocytes are actively eliminated through the interaction of FasL on Thcells and Fas on the activated B cells.
mAb:monoclonal antibody, are antibodies produced by a single B cell clone and bearunique specificity for antigen.
isotypicexclusion: In an individual B cells, only on of the two types of light chaingenes are expresses. This ensures that a single B cell has only one kind oflight chain.
granzyme:is a kind of cytotoxic substance produced by NK or Tc which can causehydrolysis of the intracellular proteins and lead to apoptosis.
peripheraltolerance: Mature lymphocytes in the peripheral lymphoid organs encounter selfor non-self antigens and form tolerance to tissue-specific antigens.
antigenicmodulation: The decrease or loss of tumor surface antigens caused by humoralimmune responses against tumors.
MHCrestriction: TCR can only recognize peptides presented by self MHC molecules.That is to say, the interaction between APC and T lymphocytes is restricted byself MHC molecules.
ITAM:is a conserved structure which has two repeated sequence tyr-X-X-leu in manymolecules in the immune system, and participate in the activation signaltransduction. When the receptor binds with the ligand, the ITAM will becomephosphorylated and provide places for other molecules to attach and inducedownstream activation activity.
positiveselection: Thymocytes whose TCR binds with peptide-MHC complex of thymic epithelialcells with low avidity are stimulated to survive, while thymocytes whose TCRcannot bind with peptide-MHC molecules on thymic epithelial cells undergoapoptosis.
BCRcomplex: BCR complex is composed of BCR(a heterodimer)which is responsible forantigen recognition and CD79a, CD79b which is responsible for activation signaltransduction.
MALT,mucous-associated lymphoid tissue, is a component of immune system associatedwith respiratory, digestive and urogenital tract, which is involved in theimmune response to inhaled or ingested antigens or microbes.
epitope:are small particular chemical groups existing in antigen which combine withTCR/BCR or Ab.
antigenicvalence: The total number of epitopes that can be bound by antibody orantigenic receptors of lymphocytes.
MAC:The complex formed by C5b,C6,C7,C8 and C9 and is the common final pathway of Cactivation, which form a hole in the cell membrane and lead to lysis of thecell.
directrecognition: Intact MHC molecules are displayed by the cells of the graft andrecognized by recipient T cells without a need for processing of host APCs.
indirectrecognition: Allogenic MHC molecules are captured and processed by host APCsand peptides derived form MHC are presented to recipient T cells by self MHCmolecules.
hypersensitivity:An excessive or inappropriate immune response against a repeated challenge withthe same antigen that results in tissue damage or functional disorder.
anchorsites: are two or more sites on the antigenic peptides binding with the MHCmolecules.
TAA:Antigens that express highly in the tumor cells and also express few in thenormal cells.
coreceptor:Coreceptors of T or B lymphocytes can bind with the antigen or MHC moleculesand participate in the signal transduction of activation signal and increasethe affinity of antigen to the receptors.
somatichypermutation: The HVR region of mIg is easy to mutate, which may generate mIgwith high affinity to antigens. Cells binding with high affinity to antigenswill survive and the affinity of B cells to antigens thus increase, which iscalled affinity maturation. hapten
: antigens which can combine with thecorresponding antibody or sensitized T lymphocytes but cannot stimulate theimmune response independently.
clonal anergy: Exposure of mature T lymphocytes toan antigen in the absence of costimulation may make the cells incapable ofresponding to that antigen.
superantigens:Antigens which can nonspecifically activate a plenty of lymphocytes and inducea very strong immune response with an extremelylow concentration.
consensusmotif: Antigenic peptides binding with the same kind of MHC molecules have thesame or similar anchor sites and anchor residues, the latter are calledconsensus motifs.
antigenicdeterminants: are small particular chemical groups existing in an antigen whichcombine with TCR/BCR or antibody.
artificialpassive immunity: A method to acquire the passive immunity which is conferredby adoptive transfer of antibody or T lymphocytes specific for the microbe.
artificialactive immunity: A method to acquire the active immunity which is induced byexposure to a foreign antigen. The immunized individual plays an active role inresponding to that antigen.
CD:The same differentiation antigens recognized by different mAbs from differentlabs.
Mitogen:Substances frequently derived from plants or microbes which can stimulatemitosis and lymphocyte transformation in an non-specific way.