Work- Immunology

Immunolongy- part 1.

Alpha-macroblobulin: A protease inhibitor in plasma that is a component of innate immunity. It inhibits proteases that are produced or acquired by bacteria to aid their invasion.

Activation-induced cytidine deaminase(AID): Enzyme that deaminates DNA at cytosine resides, converting them to uracil. The activity of this enzyme and the consequent repair of the damaged DNA are the basis of somatic hypermutation and  isotype switching in activated B cells.

* Deamination: removal of an amino group from a molecule.

*somatic hypermutation: DNA recombination that occurs between gene segments in the immunoglobulin loci and T-cell receptor loci in developing B cells and T-cell, respectively. It generates a complete  exon composed of a V gene segment and a J gene segment that encods the variable region of an immunoglobulin or T-cell receptor polypeptide chain.

* isotype switching: The process by which a B cell changes he class of immunoglobulin it makes while the anitgenic specificity of the immunoglobulin.

Acute-phase protein: Any of a number of diverse plasma proteins that are rapidly made in large amounts by the liver in response to infection.

*Actue pahse proteins induce C-reactive protein and serum amyloid A protein.
*C-reactive protein,CRP: a memeber of the pentraxin family of proteins , contains five identical subunits that form a slab-like pentameric molecule with  a hole in the middle. It can deliver pathogens to phagocytes to remove it.
* Serum amyloid A protein: a small protein which can interact with various cell-surface receptors, including Toll-like receptors and scavenger receptor to activate cells to produce inflammatory cytokines.

Affinity: measure of the strength with which one molecule binds to another at a single binding site.

Affinity maturation: The increase in affinity of the antigen-binding sites of antibodies for antigen that occurs during the course of an adaptive immune response. It is the result of somatic hypermutation of the rearranged immunoglobulin V-gene region and the consequent selection of mutated B cells that make antigen receptors of higher affinity for their antigen.

Agammaglobulinemia: An inability to make antibodies, reflected by abnormally low amounts or absence of antibodies in the blood.

Allelic exclusion: In reference to B-cell developement, the fact that each mature B cell expresses only one of the two immunoglobulin heavy chain or light cain alleles. For each locus, half of the cells in the B-cell population express the maternal allele, and the remaining cells express the paternal allele.

Anaphylatoxin: General name for complement fragments C3a and C5a, which are produced during complement activation. They induce inflammation, recruiting fluid and inflammatory cells to sites of antigen deposition.

Antibody repertoire: The total number of different specific antibodies that can be made by an individual, estimated at around 10^9

Antibody-dependent cell-mediated cytotoxicity(ADCC): The killing of anitbody-coated target cells by NK cells having the receptor FcrRIII(CD16), which recognizeds the Fc region of the bound antibody.

* Fab: Frgament antigen binding, they bind antigen and the fragments corresponding to the arms.
* Fc: Fragment crystallizable, the fragment corresponding to the stem, it readily crystallizes the effector functions of the antibody molecule by binding to serum proteins and cell-surface receptors.

* Differences in the heavy-chain C regions : 5 main isotypes. light chain has 2 isotypes: kappa > lamda

Antisera: Fluid component of clotted blood from an immune individual that contains antibodies against a given antigen. An antiserum contains a heterogeneous collection of antibodies that bind the antigen.

Autocrine: Describes a cytokine or other secreted molecule that acts on the same type of cell as the one that secreted it.

Avidity: The overall strength of binding of an antibody with multiple binding sites to an antigen(also with multiple sites), in contrast to the affinity, which is the strength of binding at a single site.

Bronchial-assoicated lymphoid tissue(BALT): The lymphoid cells and organized lymphoid tissues of the respiratory tract.

C3 convertase: any of the proteolytic enzymes that are formed during complement activation and cleave complement component C3 to C3b and C3a, thereby enabling C3b to bond covalently to antigens.

Caspase: Type of protease that is involved in generating some cytokines form their inactive pro-proteins as part of a protein comoplex called an inflammasome.

* Inflammasome: Ion channels are activated to lower the intracellular concentration of potassium ions. This ionic chnage facilitates the assembly of a protein complex through the oligomerization of a NOD-like receptor called NLRP3.

NOD-like receptor: Intracellular sensors of pathogen-associated molecular patterns(PAMPs) that enter the cell via phagocytosis or pores.

Catalytic antibody: Antibody that binds an antigen, chemically changes it, and then release it.

Chedlak-Higashi syndrome: genetic disease in which phagocytes malfunction. Their lysosomes fail to fuse properly with phagosomes, and killing of ingested bacteria is impaired.

Chemokine: Any member of a large roup of small proteins involved in guiding white blood cells to sites where their functions are needed. They have a central role in inflammatory responses.

Chimeric monoclonal antibody: monoclonal antibody that combines mouse variable regions with human constant reigons.

Chronic granulomatous disease(CGD) Immunodeficiency disease in which multiple granulomas form as a result of defective elimination of bacteria by phagocytic cells. It is caused by a defect in  the NADPH oxidase system of enzymes, which generates the superoxide radical involved in bacterial killing.

Granulomas: a structure formed during inflammtion that is found in many diseases.

Clonal Selection: The central principle of adaptive immunity. It is the mechanism by which adaptive immune responses derive only from individual antigen-specific lymphocytes, which are stimulated by the antigen to proliferate and differentiate in antigen-specific

Coagulation system: Collection of enzymes and other proteins in blood that function to form blood clots. The coagulation system is activated by damage to blood vessels.

Coding joint: The joint betwee he ends of two rearragned immunoglobulin or T-cell receptor gene segments.(VDJ)

Commensal microoraganism: A microorganism  that habitually lives on or in the human body; one that normally cuases no disease or harm and can be beneficial.

Complement: Collection of plasma proteins that act in cascade of reactions to attack extracellular forms of pathogens in extracellular spaces and the blood.

Complement activation: The initiation of a series of reactions involving the complement proteins present in plasma and extracellular fluid and leading to the death and elimination of the pathogen. It can be triggered either directly or indirectly by the presence of a pathogen.

Complement fixation: The covalent  attachment of C3b or C4b to pathogen surfaces, which is a central feature of the action of complement because it facilitates phagocytosis of the pathogen.

Complementarity-determining regions(CDRs): Short region of high diversity in amino acid sequence within the variable region of immunoglobulin and T-cell receptor chains. There are three regions in each variable region, which collectively contribute to the antigen-binding site and determine the antigenic specificity.

C-reactive protein(CRP): Soluble acute-phase protein that binds to phosphorylcholine, a surface constituent of various bacteria. It binds to bacteria, opsonizing them for uptake by phagocytes. It can also activate the classical pathway of complement fixation and bind to Fc receptors.

*Opsonization: Phenomenon by which a coating of antibody facilitates phagocytes.

Defensin: Any member of a large family of small antimicrobial peptides 35~40 amino acids that can penetrate microbial membranes and disrupt their integrity. They are present at epithelial surfaces and in neutrophil granules.

* Neutrophil: most abundant of the granulocytes, specialized in the capture, engulfment and killing of microorganisms.

Discontinous epitope: An antigenic structure on a protein that is formed from several separate regions in the primary sequrence of a protein brought together by protein folding.

Edema: Abnormal acculmulation of fluid in connective tissue, leading to selling.

Epitope: The protion of a n antigenic molecule that is bound by an antibody or gives rise to the MHC-binding peptide that is recognized by a T-cell receptor. Also called an antigenic determinatn.

Extravasation: The movement of cells or fluid from within blood vessels to the surrounding tissues.

Flow cytometry: A technique in which individual cells can be counted or identified by their cell-surface molecules after fluorescent labeling.

Genetic polymorphism: Variation in a population owing to the existence of two or more alleles of a given gene.

Germinal center: An area in secondary lymphoid tissue that is a site of intense B-cell proliferation,slection, maturation, and cell death.

Germline form or germline configuration: The unrearranged oranization of the immunoglobulin and T-cell receptor genes in the DNA orf germ cells and in somatic cells other than T cells and B cells.

Granuloma: A site of chronic inflammation usually tirggered by persistent infectious agents such as mycobacteria, or by a non-degradable foeign body.

Gut-associciated lymphoid tissue(GALT): All lymphoid tissue closely assoicated with gastrointestinal tract, including the palatine tonsils, peyer's patches in the intestine and layers of intraepithelial lymphocytes.

Hematopoiesis: The generation of the cellular elements of blood, including the red blood cells, white blood cells, and platelets.

*White blood cells(leukocytes): The cells of the immune system that are involved in protecting the body

*Platelets: thrombocytes, component of blood whose function is to reat to bleeding from blood vessel injury.


Humanize: It refers to the process by which a mouse monoclonal IgG having high affinity and specificity for an antigen of clinical interest is converted into an antibody that resembles a human IgG but retains the specificity and affinity of the mouse antibody.

Hybridoma cell line: It makes monoclonal antibodies of defined specificity. They are formed by fusing a specific antibody-producing B lymphocyte with a myeloma cell that grows in tissue culture and does not make any immunoglobulin chains of its own.

Hyper-IgM syndrome: Genetically determined immunodeficiency disease in which B cells cannot switch their immunoglobulin heavy-chain isotype, and so make unusually high amounts of IgM and no ther isotype. It leads to abnormal susceptibility to infections with pyogenic bacteria.