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| any agent causing disease. Most commonly is referred to infectious organisms, such as bacteria, viruses and fungi, but noninfectious chemical agents also could play a role of pathogen. |
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| is any molecule (deriving from either any pathogen or commensal organisms and even self tissues) triggering production of antibodies. |
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| is the difference in antigen strength that triggers an immune response. It defining factors are (1) chemical structure/ composition and (2) density of epitopes. |
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| is a biomolecule that can trigger different intensities of immune response (proteins trigger the strongest). |
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| is a small molecule that can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one that also does not elicit an immune response by itself. |
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| is an agent that may stimulate the immune system and increase the response to a vaccine, without having any specific antigenic effect in itself. |
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| is an area of optimal precipitation reaction between antigen and antibody for testing purposes |
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| is marked in order to be visualized in testing methods. |
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| Anti-human immunoglobulin in capture assays |
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| detect bound antibody in ELISA testing for HLA antibodies. |
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| H and L chains in antibody molecule |
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Definition
| are the components of the structure of the antibody molecule. The Heavy chain is on the inside of the structure and has a constant and variable region; the light chain is on the outside of the molecule and has a variable chain and a constant region. The heavy and light chains are held together by disulfide linkages. |
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| occurs on activated B cells in secondary lymph tissues. |
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| is used to produce monoclonal antibodies; it results from fusion of the Myeloma cell & Plasma cell from an animal immunized with antigen of interest. |
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| are stored after the first encounter with an antigen. They are utilized upon second encounter and produce a stronger and faster immune response. |
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| Antibody molecule structure |
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Definition
| structure is made up of the upper half (variable heavy and variable light) FAB portion, and the lower half (constant heavy and constant light) Fc region. |
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| is a low affinity Fc receptor found on NK cells, neutrophils, monocytes and macrophages. |
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| is the strength of the reaction between a single antigenic determinant and a single combining site on the antibody |
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| is a measure of the overall strength of binding of an antigen (by its multiple epitopes) with multivalent antibodies |
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| are signaling molecules, usually proteins, produced by one cell and transmitting a signal to another (or itself). Cytokines are termed also lymphokines & Interleukins. |
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| are biological barriers in innate immunity. |
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| are molecules that cause harm to the body and are removed from the body |
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| is a T cell ligand, binds to CD40R on B cells or dendritic cells as a co-stimulatory event, it is not a second signal, but it is important in T cell activation. |
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| is the differentiation of the mature blood cells with their distinct and unique functions from a single ancestor/progenitor cell that is a pluripotent hemopoietic stem cell. Lymphoid lineage produces T cells, B cells and Natural Killer cells. Myeloid lineages produce red blood cells, macrophages, and granulocytes. |
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| has the ability to recognize self from non-self, but does not have the ability to allow innate immunity cells (macrophages, neutrophils, dendrites, and natural killer cells) to clonal expand. |
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| is the system in which antigen recognizes one cell, the cell on which the antibody recognizes the antigen goes into clonal expansion and produces memory cells (T and B Cells). |
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| prevents abnormalities in self tolerance maintenance |
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| is non reactivity to autoimmune cells or transplantation involves deletion of autoreactive clones during development stages, induction of anergy (activation of naïve T cells require co-stimulation, which is absent in contact with self Ags, limited access of T cells to the majority of tissues (in the absence of inflammation)and suppression of T cell activation by Treg cells. |
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| is tolerance to transplantation |
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| can lead to recruitment of inflammatory cells, opsonization via c3b for phagocytosis or membrane attack complex. There are three different pathways: mannose-lectin, classical and alternative. |
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| is part of the Mannose-binding lectin (MBL) enzyme that is a lectin that binds to mannose-containing carbohydrates of all microorganisms & is part of the lectin pathway of complement activation. |
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| are produced in response inflammation; they are mannose-binding lectin and C - reactive protein. |
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Definition
| activates the classical pathway of complement activation by binding to the pathogen and to C1 to activate internal cleavage and activation. |
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| is an acute phase protein produced during inflammation. They recruit immune cells to the site of infection and induce enzymes to degrade the extracellular matrix. |
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| is activated by MBL binding to mannose of the cell surface of the pathogen. It cleaves C4 into C4b and C4a, C4b sticks to cell surface. Then it cleaves C2, C2a sticks to C4b which creates the classical/lectin C3 convertase, which can now cleave C3 and allow C3b to stick to cell surface. |
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| Germinal centers of lymph nodes |
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Definition
| contain B cells. Activated B cells initiate formation of germinal centers from primary follicles, where isotype switching & somatic hypermutation occur. |
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Definition
| is traffic patterns of cells regulated by chemokines |
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Definition
| is human leukocyte antigen. It is the MHC molecules in humans. MHC class 1= HLA-A,B,C,F,G and MHC class II = HLA-D(M,O,P,Q,R) |
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Definition
| is any molecule on or in the cell which could be recognized, using specific stains or labeled antibodies, and thus could allow identification of that cell |
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| is a system of the clusters of differentiation (or designation) that was established in the 1st International Workshop on Human Leukocyte Differentiation Antigens (1982, Paris) to standardize the nomenclature of the cell surface molecules and corresponding antibodies |
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Definition
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| Negative selection in bone marrow |
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Definition
| of self reactive clones (immature B cells) |
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| Negative selection in thymus |
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Definition
| of self reactive T cells via dendritic cells. T cells that bind too tightly to MHC molecules with self antigen are destroyed. |
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Term
| Development of mature naïve antigen specific B cells |
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Definition
| arises from the bone marrow, and move into peripheral circulation. They met up with dendritic cells in primary follicles and become mature in that they have IgM on their surfaces. |
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| Development of mature naïve antigen specific T cells |
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Definition
| positive selection for T cells that bind to peptide/MHC complex on epithelial cells of thymus, then negative selection of T cells that bind too tight to dendrites produces single positive immature naïve T cells. |
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| Peripheral lymphoid organs |
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Definition
| are the lymph nodes, spleen, peyer’s patches (lymph nodes in intestines), Mucosal associated lymphoid tissue and tonsils) |
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| are where B cells are, when they are primed with antigen they become germinal centers |
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| are where the activated B cells are (primed with antigen). |
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Definition
| have not yet met antigen to which their receptor could bind to, they circulate in the peripheral lymph tissue |
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Definition
| have not yet met an antigen to which their receptors could bind to; they also circulate in the peripheral lymph tissue. |
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Definition
| are antigen primed, and can go into clonal expansion and isotype switching (from IgM). |
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Definition
| are activated by dendritic cells that bring antigen to secondary lymph organ. They present to antigen to the T cell (via MHC 1 (Cytotoxic T cells) or MHC2 (Helper T cells)) and that T cells differentiates into an effector cell and can go through clonal expansion. |
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Definition
| are in the bone marrow and undergo Rearrangement of light chain, Allelic exclusion (light chain) and assembly of IgM molecule in ER |
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Definition
| B cell encounters a pathogen in the periphery, and cross-links to its epitopes. It brings that antigen back to the T cell zone in the peripheral lymph tissues where it presents to helper T cells via MHC 2 and T helper cell activates B cell via co stimulatory molecules (CD40L on T cells and CD40R on B cells). Dendrites can also present to T cells in T cell zone to prime them to a specific antigen. They need a second co stimulatory signal which is made up of B7 on dendrites and CD28 (CTLA4) on T cells. CD28 causes activation and clonal expansion, CTLA4 causes inhibition of immune response. |
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Definition
| 1st signal: TCR with MHC/Ag complex and 2nd signal: CD28 (receptor on T cell) with B7.1 or B7.2 (its corresponding ligands on DCs). |
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Definition
| requires cross-linking of immunoglobulins with epitopes on pathogen surface and other requires signals involving CD19/21 and CR2. B cells can also be activated by T cells in which they are primed for the same antigen. They met in the T cell zones and connect via CD40L on T cells and CD40R on B cells, and then T cell can release IL-4 and IL-5 to activate the B cell into clonal expansion, isotype switching or differentiation into plasma cells. |
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Definition
| class 1 is on all nucleated cells, interacts with cytotoxic T cells. MHC class 2 is on antigen presenting cells, glial cells and epithelial thymus cells, it presents to helper T cells. Their function is to present peptide fragments of antigen to cells to prime them. |
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Definition
| are thymocytes from the bone marrow before they enter the thymus; it has CD2 on its surface. |
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Definition
| express CD8 and CD4 on their surfaces before negative selection and positive selection |
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| results from negative and positive selection |
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produced from B cell/T cell activation under influence of IL-4
The memory T & B cells are the key elements to long-lived specific immunity, which is responsible for stronger and faster immune responses to subsequent encounters with the same pathogen |
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Definition
| immature dendrites acquire antigens & start to differentiate into mature dendrites(they lose ability for phagocytosis while acquiring ability to express chemokine & other receptor & ligands enabling them to traffic to & to interact with T cells). Mature dendrites transport antigen from the center of infection to the T cells zones in the secondary lymphoid tissues. The minute fraction of the naïve T cells, which have specificity of their antigen-recognition sites on the TCRs to the antigen delivered by dendrites, interact with these Ags in the context of their MHC Class I, or Class II molecules, thus becoming activated into effector TC, or TH cells, respectively. Via different set of cytokines dendrites promote further differentiation of the TH cells into Th-1 & Th-2 subclasses (IFNg & TNFb for Th-1 and IL-4, IL-5 & IL-13 for Th-2) |
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Definition
| degranulation when the IgE linked to their Fc receptor cross-links with an antigen. Degranulation of histamine causes 1) increased fluid secretion and increased peristalsis in the GI tract which causes vomiting and diarrhea, 2) decreased diameter and increased mucus secretion in the airways which leads to coughing and 3) increased blood flow and increased permeability in the blood vessels which leads to edema, inflammation and increased lymph flow and carriage of antigen to lymph nodes. Also secrete leukotrienes. They are residents of the connective tissue ( type I hypersensitivity) |
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| Cytokines produced by macrophages |
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Definition
| are IL-1, IL-6, INF1, IL-12, chemokines and GM-CSF. Th1 cells produce IL-2 and INFgamma to activate macrophages, and Th2 produces IL-4/5 to activate B cells to produce antibodies. |
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Definition
| is produced by macrophages in response to pathogen, it activates lymphocytes and causes liver to produce IL-6, involved in innate immunity |
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Definition
| produced by Th1 cells along with INFgamma to activate macrophages, also produced by recently activated T cells in interaction with naïve T cells to activate them to become effector cells and kill infected cell. |
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Definition
| has numerous functions in regulating Hemopoiesis, from induction of differentiation of the pluripotent hematopoietic stem cells into both myeloid and lymphoid lineages (depending on its synergistic interactions with other hematopoietins) to activation and controlling the functions of the mature cells, mostly myeloid lineage differentiation |
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Definition
| B cell activation to turn into memory cells (when interacting with T helper cells). The first time the T and B cells met, the Th2 cell needs to release IL-4 in order to get B cells to differentiate and proliferate. Dendritic cells also produce IL-4 in order to get T cells to differentiate into th2 cells. |
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| inflammation, produced by macrophages in response to pathogen activation, stimulates liver to synthesize more acute-phase proteins |
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| Hemopoiesis, Hematopoietin that stimulate production of interleukins, lymphoid lineage differentiation |
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| NK and Tc cells activation, in Innate Immunity IL-12 stimulates production of tumor necrosis factor-alpha (TNF-α) and mediates enhancement of the cytotoxic activity of NK cells. In adaptive immunity it stimulates the production of interferon-gamma (IFN-γ) mediates enhancement of the cytotoxic activity of CD8+ TC cells, is a T cell stimulating factor and growth factor and it promotes differentiation of naive T cells into Th1 cells. Tc cells trigger secretion of the IL-12 by DCs, which activates Tc & NK anti-viral activity. |
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Definition
| CSFs (GM-CSF: granulocyte/monocytes colony stimulating factor, G-CSF: granulocyte stimulating factor, and M-CSF: monocyte stimulating factor) Macrophages produce GM-CSF in response to pathogen activation. |
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Definition
| two types INF 1 = alpha and beta, and INF 2 gamma. INF 1 is produced by macrophages in response to pathogen activation, which activate natural killer cells, antiviral. |
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Definition
| produces INFγ in the case of an intracellular invasion. INFγ causes activation of macrophages and B cells to produce opsonizing antibodies (cellular immunity). |
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Definition
| produced by macrophages in response to pathogen activation, produces systemic inflammation, pyrogen |
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| Transforming growth factor |
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Definition
| chemokine that mediate innate response, mediate Treg cells. The overall function of TGF-β is to down-regulate the inflammatory response, it is a negative feedback mechanism ‘switching off’ the inflammation-related reactions of the immune system when they are no longer needed. It suppresses proliferation & differentiation of the immunocompetent & somatic cells, It is involved in regulation of cells apoptosis and it Inhibits activation of macrophages |
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| Chemokines and cell adhesion molecules |
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Definition
| (IL-1 promotes secretion) Point of destination & pace of the traveling cells are defined by their repertoire of the chemokine molecules. CAMS regulating pattern of the cells trafficking, CAMs typically are transmembrane receptors which belongs to 4 groups (ICAMS, Integrins, addressins and selectins) |
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Definition
| - There is an α and β chain which recognize the antigen , There are two CD3 receptors made up of 2ε chains, and one or two γ or δ chains which stabilize the TCR, There are two intracellular ζ chains which transmit the signal |
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Definition
| regulate humoral responses; bind IgG through its Fc region, IgG attached to pathogen |
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| T cell co receptors, made up of 2ε chains, and one or two γ or δ chains which stabilize the TCR |
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Definition
| helper T cell cooperates with B cells or other helper T cells. Also T regulatory cells suppress immune response and involved in peripheral tolerance |
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| Cytotoxic T cell, effector function in immune response |
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| Fas Ligand (FasL or CD95L) is a type-II transmembrane protein that belongs to the tumor necrosis factor (TNF) family. Its binding with its corresponding receptor induces apoptosis |
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| ( B cells and Dendritic cells) necessary when B cells present to Th2 cells which leads to clonal expansion, B cell has CD40R, T cell has CD40L. CD40/CD40L is co stimulatory signals for T cells and Antigen presenting cells (dendrites) |
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Definition
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CD28 on T cells interacts with B7/CD80/CD86 on dendrites, promote immune cell response
CTLA4 on T cells interacts with B7 on dendrites, inhibits immune response |
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Definition
| (encode proteins involved in cell division): Growth factors & their receptors, Signaling pathways and Genes transcription |
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Definition
| encode proteins that prevent the proliferation of mutant cells |
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| Oligoclonal bands on electrophoresis |
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Definition
| Electrophoresis of CSF for immunoglobulins). Four to eight bands are diagnostic for Multiple sclerosis, common test for diagnosing MS. |
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Definition
| Molecular-based HLA genotyping methods use polymerase chain reaction (PCR)-based amplification of HLA genes. This technique is based on isolating & amplifying a sequence of DNA that is specific to a particular Ag Extremely high both: Sensitivity (94.7%) and Specificity (98.6%). |
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Definition
| Semi-automatic, Extremely fast, Quantitative method, Can discriminate between antibiotics (Azithromycin)-resistant strains of the Treponema pallidum from antibiotics-susceptible strains, Very important for clinical implications, not yet standardized method and hence no commercially available kits |
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Definition
| is a single-diffusion technique in which antibody is evenly distributed in the support gel. Antigen is applied to a well cut into the gel & diffuses out from the well forming complexes with antibody. The area of a resulting ring of the lattice is measured and estimated in comparison with standard curve made with titrated amounts of antigen and antibody. |
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Definition
| is the line in rocket immunodiffusion that detects the amount of tested antigen |
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Definition
| Enzyme-linked immunosorbent assays (ELISA) utilize purified HLA Ags bound to the wells of the Microtiter plates, Patient’s serum is added to the wells of the plate, If anti-HLA Abs are present in the test sample, they bind to Ags attached to the wells, The bound Abs are then detected by addition of an enzyme-labeled anti-immunoglobulin Ab, Addition of a substrate results in a color change in the wells that contain bound Abs |
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Definition
| testing Is of limited use (not always sufficient level of Abs; IgM Abs are not specific for acute phase & they are note detectable until late stage) |
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Definition
| (enzyme immuno assay) - heterogeneous, Enzyme-labeled Ag competes with unlabeled patient’s Ag for a limited number of binding sites on Ab molecules that are attached to a solid phase. After carefully washing to remove any nonspecifically bound Ag, enzyme activity is determined. Enzyme activity is inversely proportional to the concentration of the test substance, meaning that the more patient Ag is bound, the lass enzyme-labeled Ag can attach |
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Definition
| RIA (radio labeled immuno assay) presents a health hazard but very sensitive method |
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Definition
| high sensitivity and specificity Electrophoresis of protein (Abs from the serum), Transfer onto nitrocellulose membrane, 10 (primary) specific anti-Ig Ab, 20 (secondary) Ab, labeled with horseradish peroxidase (which cleaves a chemiluminescent agent), The produced luminescence is proportional to the amount of the estimated Ab, A photographic film is placed against the membrane, and exposure to the light from the reaction creates an image of the antibodies bound to the blot. Can be used as a confirmatory test for HIV, Lyme disease and syphilis |
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Definition
| caused by EBV, Serological findings: Heterophile Abs & Abs to EBV Ags |
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Definition
| infectious bacteria, spirochete |
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Definition
| Reagin II tests: Reagin II test uses a cardiolipin antigen (as in the VDRL test) and allows screening of a large numbers of samples because it’s very sensitive |
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Definition
| Rapid plasma reagin (RPR) test is a modified VDRL test involving macroscopic agglutination, and is more sensitive test for diagnosis of primary syphilis |
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Definition
| is transplant from own tissue |
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Definition
| is transplant from same species |
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Definition
| is transplant from different species |
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Definition
| transplant rejection within the same species |
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Definition
| transplant rejection from different species |
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| syngeneic transplantation |
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Definition
| is between two identical twins |
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| Graft versus host disease |
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Definition
| T cells from the transplant is activated in the lymph nodes by the recipient’s DCs. The primary targets for GVHD are skin, intestinal epithelium & liver (highly proliferative tissues). |
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Definition
| When MG Ab combines with the receptor site, binding of ACH to the receptor is blocked (impaired function of neurotransmission), which leads to progressive muscle weakness and eventually receptors are destroyed |
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Definition
| an autoimmune disorder of the central nervous system that is characterized by formation of plaques in the white matter of the brain and spinal cord. These plaques are mainly composed of T cells and macrophages that are involved in the demyelination leading to neurodegeneration |
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Definition
| hyperplasia of the thyroid & hypothyroidism due to infiltration with T & B cells (with T cells predominating), macrophages and plasma cells. Development of the germinal centers replacing the normal thyroid gland |
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Definition
| hyperplasia of the thyroid & hyperthyroidism. With symptoms of the thyrotoxicosis due to patchy lymphocytic infiltration (T & B cells) and hyperplasic epithelium |
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Definition
| a systemic autoimmune disease in which the exocrine glands producing tears and saliva are destroyed |
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Definition
| symmetrical skin thickening |
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Definition
| is a term for cases when there is some similarity of the pathogenic epitopes with those of the self tissues |
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Term
| Molecular mimicry example |
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Definition
| In Rheumatic Fever an autoimmune inflammatory process develops in the heart, joints & kidneys 2 to 3 weeks after a throat infection with Streptococcus pyogenes. This autoimmune process is due to the fact that these organs have epitopes with resemblance with the antigenic epitopes of Streptococcus pyogenes |
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Definition
| Occurs when allergens enter the blood stream and mast cells degranulation which causes vascular permeability and muscular constriction of smooth muscle. Swelling of the airways and epiglottis causes choking |
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| Epstein barr virus infection |
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Definition
| EBV causes: Infectious mononucleosis (IM) Lymphoproliferative disorders and Several malignancies |
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Term
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Definition
| is a term for inflammatory process in the liver (A-E) |
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Definition
| IgE antibodies were produced during earlier encounter with antigen. The IgE antibodies remain bound to the Fc Receptors attached to mast cells, eosinophils and basophils. This complex makes these cells antigen specific. When the antigen comes back into the body, the IgE antibodies attached to mast cells (via Fc) cross-link and cause the mast cell to degranulation and release histamine into the environment. Histamine results in contraction of muscles, increased vessels’ permeability and secretion of mucus. This causes expulsion of GI tract or airways and inflammation to blood vessels. |
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Term
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Definition
| : caused by antibodies specific for altered components of the human cells. Usually a drug modifies an epitope on a human cell, which causes it to be recognized as foreign. The now foreign cell is acted upon by IgG, which binds and promotes complement fixation. Complement fixation can lead to membrane attach complex or phagocytosis. |
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| Type III hypersensitivity |
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Definition
| smaller immune complexes (IgG) from regular immune responses are not efficiently fixed via complement. They circulate in the blood and eventually stick to blood vessel walls. After enough of them have accumulated, they become large enough to fix complement and interact with immune cells (i.e. Mast cells and Fc receptor). This interaction leads to histamine release and recruitment of platelets and inflammatory cells to the blood vessel. Clots cause the blood vessel to burst. |
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Term
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Definition
| First the foreign peptides-derived antigen is presented by macrophages & dendritic cells to that Antigen-specific memory T cells (which exited from blood into tissue). As a result a TH-1 response is generated locally & induced further inflammatory reactions, mediated by TH-1 panel of cytokines |
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Definition
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Term
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Definition
| is used to produce monoclonal antibodies; it results from fusion of the Myeloma cell & Plasma cell from an animal immunized with antigen of interest. |
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