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MICR 386 Midterm
| Term | Definition |
|---|---|
| immunology | study of immune system and its responses to invading pathogens/foreign substances |
| immune system | collection of cells, tissues and molecules that respond to infections |
| immune response | coordinated reaction of immune cells, tissues and molecules to microbes and foreign materials |
| components of immune system | lymphatic vessels, primary and secondary lymphatic organs |
| lymphatic vessels | thinly walled vessels through which the fluids and cells of the lymphatic system move through the lymph nodes and ultimately into the thoracic duct where they join the bloodstream |
| primary lymphatic organs | thymus, bones marrow |
| secondary lymphatic organs | adenoids, tonsils, bronchus associated lymphoid tissue, lymph nodes, spleen, intestines, peyer's patches, appendix |
| innate immunity | physical barriers, chemical elements and innate immune cells that act in a protective manner against environmental or infectious agents |
| adaptive immunity | B and T lymphocytes, first encounter of pathogen develops primary immune response involving both, some cells develop into memory cells to recognize pathogen and respond more efficiently during secondary response |
| surveillance | innate and adaptive act together to detect foreign or defective cells, help prevent proliferation of dangerous cells withing body systems |
| microbes | microorganisms that cause disease |
| macromolecules | larger nonliving molecules found in food, drugs and chemicals |
| cells | capable of distinguishing between self and nonself to target nonself |
| allergic reactions | bodys immune system overreacts to substances that are usually not harmful |
| autoimmune disease | body incorrectly identifies self cells as nonself, considered hypersensitivity diseases |
| laboratory tests | used to analyze state of immune system |
| vaccination | public health strategy to boost immune defenses of individual and population |
| characteristics of innate immunes system | unchanging, immediate, nonspecific reactivities, broad range of targets, no memory |
| unchanging | continuous protection without any rearrangement or alteration in response |
| immediate | response occurs within minutes |
| nonspecific reactivities | can be to common component on mutliple pathogens |
| no memory | not improved by repeated exposure |
| broad range of targets | any elements identified as foreign elicits response |
| physical barriers | mucous membranes, cilial hairs, epithelial barriers |
| muscous membrane | trap pathogens and foreign materials |
| cilial hairs | move trapped pathogens out of the respiratory system via sweeping |
| epithelial barriers | skin, GI tract, respiratory tract produce peptides with natural antibiotic function |
| chemical barriers | secretion, sebaceous gland secretion, commensual organisms in gut and vagina, spermine in sperm, acid pH of stomach |
| secretion | tears, siliva and nasal secretion contains lysozymes |
| sebaceous gland secretions | glands deposit sebum that inhibits bacterial growth |
| commensual organisms in gut and vagina | protect from pathogen colonization by reducing pH |
| spermine in sperm | free radical savenger to prevent damage to DNA |
| acid pH of stomach | pathogens ingested cannot survive pH |
| leukocytes | type of white blood cell identify and eliminate foreign invaders several types |
| phagocytes | neutrophils, macrophages, dendritic cells |
| neutrophils | first responding, migrate to site of inflammation and ingest microbes, increasingly segmented as mature 50-70% of cells |
| macrophages | ingest aged neutrophils and bacteria, secrete cytokines to stimulate inflammation and recruit other immune cells 1-6% of cells |
| dendritic cells | found on tissues in contact with environment, serves as link between innate and adaptive |
| granulocytes | neutrophils, eosinophils, basophils, mast cells |
| eosinophils | secrete histamines and free radicals during parasitic infection, mediators of allergic reaction 1-3% of cells |
| basophils | secrete heparin and histamine in response to parasites and allergic reaction <1% of cells |
| mast cells | role in allergy and anaphylaxis, releasing heparin and histamine rich granules, protective role in wound healing, angiogenesis and blood brain barrier function <1% of cells |
| natural killer cells | large granular cytotoxic lymphocytes with no T or B cell receptor fundamental role in surveillance of altered cells |
| complement protein | mark pathogens for destruction |
| mannose binding lectin (collectin) | involved in opsonization of microbes and activation of complement |
| opsonization | process used to tag foreign pathogens for elimination by phagocytes |
| c reactive proteins (pentraxin) | involved in opsonization of microbes and activation of complement system |
| coagulation factors | involved in coagulation of blood and repair of a damaged vessel |
| responses of innate immunity | inflamation and coagulation, phagocytosis |
| steps of phagocytosis | attachment, ingestion, fusion, digestion, release |
| phagocytosis | important method of eliminating invading pathogens activated by recognition of PAMPs |
| attachment | many surface receptors exist to bind to microbes for phagocytosis |
| LPS receptor | lipopolysaccharide of gram negative bacteria initiates inflammatory signal cascade |
| scavenger receptor | family of receptors for wide variety substances therefore wide variety of ligands |
| mannose receptor | exclusive to microbes, acts as pattern recognition receptor for several microbes |
| N-formyl-methionyl receptor | bacteria produce fMLP which has amino terminal N-formylated methionine, recruit inflammatory cells |
| types of attachment | unenhanced, enhanced |
| unenhanced attachment | nonspecific recognition of PAMPs through PRRs 4 previously discussed |
| enhanced attachment | attachment to an opsonized microbe occurs via IgG antibodies, complement or acute phase proteins |
| ingestion | pseudopods surround and engluf microbe electron pump brings protons into phagosome, lowering pH |
| fusion | phagocytes contain lysosomes that travel along microtubules and fuse with phagosome to create phagolysosomes |
| lysosomes | organelle containing proteolytic enzymes |
| digestion | mcirobes are broken down by lysosomal enzymes in phagolysosomes |
| release | residul bodies are released via exocytosis |
| residual bodies | indigestible materials remaining in vesicles |
| characteristics of adaptive immune system | discrimination, diversity, specificity, specialization, memory, self limitation |
| discrimination | ability to discriminate between self and nonself prevents host injury during response |
| diversity | responds to wide variety of microbes and molecules |
| specificity | distinguishes subtle differences among foreign antigens |
| specialization | response is antigen dependent, ensuring optimal defense against each type of microbe |
| memory | enhanced response to microbe following repeated exposures |
| self limitation | cells allow microbe activated immune response to return to basal state |
| professional antigen presenting cells | MHC class 1 and 2 dendritic cells, B lymphocytes, neutrophils and macrophages |
| nonprofessional antigen presenting cells | MHC 1 all nucleated cells |
| MHC | major histocompatability complex |
| lymphopoiesis | differentiation of lymphoid cells from hematopoietic stem cells |
| t cells | cells with T cell receptors help in cell mediated and humoral immunity |
| helper T cells (TH) | express CD4 coreceptors, involved in killing of target cells |
| cytotoxic T cells (TC) | express CD8 coreceptors involved in killing of target cells |
| TH1 | activate macrophages, responsible for cell mediated immunity |
| TH2 | cause mature B cells to become plasma B cells and produce antibodies for humoral immunity |
| immunoglobulin | antibody |
| b cells | prescense of B cell receptor on surface responsible for antibody mediated immunity express B7 and CD40 |
| immature B cell | express cell surface IgM |
| mature B cell | express both IgM and IgD on surface |
| plasma B cell | secretes antibodies following antigen stimulation |
| memory b cell | involved in secondary antibody response |
| IgA | high concentration in mucous membranes, acts as neutralizing antibody to prevent antibody attachment to epithelial cells |
| IgD | small amount in blood, no known effects |
| IgE | found on lungs, skin and mucous membranes plays rule in anaphylaxis by releasing histamines and protects against parasites` |
| IgG | 4 subclasses found in all bodily fluids fighting infections only antibody to pass onto placenta and fetus |
| IgM | largest, found primarily in blood and lymoh excellent complement activator |
| immunogenicity | abililty of a substance to induce a humoral/cell mediated immune response |
| immunogen | molecule that has the ability to evoke a specific immune response and can react with the resultant specific immunity |
| antigens | a molecule that can react specifically with either a preformed antibody, immunoglobulin receptors on B cells or T cell receptors |
| properties of immunogens | foreigness, molecular size, molecular complexity, degradability, physical form |
| foreigness | greater the phylogenetic distance greater structural disparity and therefore greater immune response |
| xenogeneic | different species |
| allogeneic | different individuals of single species |
| syngeneic | similar genetics |
| isogeneic | same genetics |
| molecular size | larger the molecule, greater the immunogeneic property |
| molecular complexity | internal molecular complexity is necessary |
| degradability | easily phagocytosed antigens are more immunogeneic |
| particulate vs soluble | particulate is more immunogeneic |
| particulate | aggregates of protein |
| denatured vs native | denatured more immunogeneic due to loss of tertiary structure and therefore different parts of peptide exposed |
| denatured | loss of structural integrity in a protein |
| haptens | small organic molecule that is antigenic but not immunogeneic unless it is attached to large carrier protein |
| adjuvants | substances that enhance the immunogenecity of an antigen when injected into a human without resulting in immune response against it |
| epitope | immunologically active regions of an antigen that bind to an antigen specific T/B cell receptor on lymphocytes or to secreted preformed antibodies |
| exogenous antibodies | soluble antigens that require no antigen processing for detection |
| epitope characteristics | multivalency, immunodominance, acessibility, specificity |
| multivalency | antigens with multiple epitopes that cn be recognized by antibodies |
| homogenous | contains same epitope multiple times |
| heterogenous | expresses different epitopes, resulting in varried immune response |
| immunodominance | antigen that induces a more pronounced immune response |
| acessibility | antibody needs to be able to reach epitope |
| specificity | antiboides can have higher affinity for a certain configuration (acquired by gene rearrangement) |
| cross reactivity | ability of any antibody to react with 2+ antigens that possess a common epitope |
| herd immunity | individuals at risk for disease are protected because disease cannot spread |
| newly emerging disease | lyme (NE US), Hep C (N Africa and S US), Hendra virus (Australia) |
| re emerging disease | west nile (NE US), Dengue (Mexico), thyphoid (India) |
| active immunity | induces humoral or cell mediated immunity and memory follwing exposure to an antigen |
| natural active | follows exposure to infectious disease |
| artifical active | follows vaccination |
| passive immunity | external antibodies give immediate short lived protection |
| natural passive | transfer of maternal antibodies across placenta to fetus |
| artificial passive | concentrated immunoglobulin extracted from pooled serum and injected into susceptible individuals |
| live attentuated vaccine | contain liver virus with reduced virulence so that the virus will cause infection but no disease |
| live attentuated ex | OPV, MMR |
| killed or inactivated | microorganism killed by physical or chemical processes that therefore cannot cause disease |
| killed or inactivated ex | IPV, pertussis |
| inactivated toxins | bacterial toxin is altered to render it harmless so it will not cause disease |
| inactivated toxins ex | tetanus, diptheria |
| subunit | consist only of antigenic component of the pathogen |
| subunit ex | influenza, hep B |
| antigen shift | occurs when different types of influenza viruses infect a single cell |
| antigen drift | occurs when virus accumulates various point mutations |
| monoclonal antibodies | antibodies dervied from single B cell clone and are specific to single epitope on an antigen |
| polyclonal antibodies | heterogenous mixture of antibodies with different affinity produced by many clones of B cells, recognizing multiple epitopes on an antigen |
| enzyme linked immunosorbent assay | used to determine if a particular antibody present in blood via antiserum analysis |
| structural components of immunoglobulin | 2 heavy chains, 2 light chains, interchain disulfide bonds, intrachain disulfide bonds, variable chain regions, Fab region, Fc region, constant chain region, hinge region, domains, oligosacchariides, hypervaraible regions |
| papain | enzyme that cleaves Fc from Fab, leaving 3 segments |
| pepsin | enzyme that cleaves Fc region into fragments up to hinge, remaining fragment is called F(ab')2 region |
| serum | residual fluid when blood or plasma form a clot |
| isotype | phenotypic variation in constant regions that define each class of immunoglobulin |
| heavy chain isotype | gamma, alpha, mu, delta, epsilon |
| light chain isotype | kappa, lambda |
| allotype | occurs in constant heavy and light chain region of specific isotype, slight differences in amino acid sequences of heavy/light chain of different individuals |
| idiotypes | changes in variable region resulting recognition of epitope |
| one turn/two turn rule | states signal sequence with a one turn spacer can join only with a sequence having a two turn spacer |
| productive rearrangement | joining of VDJ segments in phase to produce a VJ or VDJ unit that can be translated in it entirety |
| nonproductive rearrangement | rearrangement in which gene segments are joined out of phase that the triplet reading frame for translation is not preserved |
| class switching | immunoglobulin class switching changes from IgM to other classes, result in antigen stimulation |
| switch sites | conserved motif upstream from |
| immunocompetent cell | mature lymphocyte capable of recognizing specific antigens mediating immun response |
| affinity maturation | increase in average affinity of antibody for antigen during course of immune response or in subsequent exposure |
| clonal detection | apoptosis of immature B cells that recognize self before fully developed |
| receptor editing | immature B cells edit light chain genes to edit receptor |
| t cell receptor characteristics | extracellular domain, transmembrane domain, cytoplasmic domain |
| extracellular domain | heterodimer of either aB or yb proteins |
| transmembrane domain | anchors TCR to cell membrane/CD3 complex |
| cytoplasmic domain | lacks large cytoplasmic domain and heavily relies on CD3 for signal transduction |
| CD4 | monomer of 4 domains marker for helper T cells |
| CD8 | either aB heterodimer and aa homodimer marker for cytotoxic T cells |
| y-silencers | determine commitment to aB or yb on=aB lineage off=yb lineage |
| pseudogenes | nonfunctional gene due to mutation |
| combinatorial V-J and V-D-J joining | generates large number of random gene combinations in TCR and Ig more in Ig due to more variable genes |
| alternative joining of D gene segments | alternative joining of D segments can occur while 1 turn 2 turn rule observed for considerable diversity in TCR but not Ig |
| junctional flexibility | joining of gene segments exhibits junctional flexibility can generate many nonproductive arrangements for both but also increase diversity |
| N region nucleotide addition | nucleotides may be added at junctions to create diversity |
| somatic mutaions | does not occur in TCR to reduce likelihood of generating self reactive t cell influence VJ and VDJ rearrangement on Ig |
| allellic exclusion | only in TCR-B and Ig |
| CDR-1 | located in variable region of TCR and interacts with peptide in MHC peptide complex |
| CDR-2 | located in variable region of TCR and interacts with a reggion of MHC peptide complex |
| CDR-3 | located in D-J region of TCR and interacts with peptide in MHC binding groove |
| stem cell | undifferentiated, self renewing, pluripotent cell which undergoes mitotic division to generate stem cells and progenitor cell |
| undifferentiated | primordial cell that has not assumed the morphological and functional characteristics it will later acquire |
| self renewing | process of giving rise to infinitely more cells of same cell type |
| pluripotent | capable of giving rise to several different cell types |
| progenitor cell | gives rise to several but not all hematopoietic lineages where it loses ability of self renewal |
| precursor | restricted to single lineage |
| cortical region | consists of large number of thymocytes where gene rearrangement and positive selection occurs |
| thymocytes | immature t cells within thymus |
| corticomedullary junction | border between cortical and medullary regions where negative selection occurs |
| medullary regions | low density of thymocytes, site of maturation |
| positive selection | first step of double selection thymocytes interact with APC's |
| engaged with MHC I | CD8 |
| engaged with MHC II | CD4 |
| no interaction in positive | apoptosis |
| negative selection | second step of double selection some may recognize APCs expressing self antigen complexes |
| no engagement | surivavl |
| engagment in negative | apoptosis |
| 1st wave of yb T cells | occur in fetus, migrate to epidermis |
| 2nd wave of yb T cells | occur in newborn, migrate to reproductive epithelium |
| 3rd wave of yb T cells | occur in adults, migrate to intestinal epithelium, skin, airway tract and uterus |
| MHC | primarily function to bind and present antigenic peptide fragments on cell surface |
| polymorphic | many existing alternative forms |
| MHC restriction | characteristic of T cells that permits them to recognize antigen only after it is processed and the resulting antigenic peptide is displayed in association with class I/II molecule |
| autoimmune disease | abnormal immune response against self |
| histocompatability | recipient can accept grafts from donors with same haplotype even if recipient expresses additional haplotypes recipient cannot accept grafts from donors with haplotyp recepient does not have, even if others are identical |
| child histone incompatible | MHC encodes major histocompatibility antigens that are not identical and therefore cannot accept grafts |
| MHC I structure | heterodimer of 43000 Da alpha chain and 12000 Da beta microglobulin chain alpha chain folds into 3 domains and beta is one |
| MHC I binding cleft | a1 and 2 fold together into it |
| MHC I distribution | expressed on all nucleated cells highly expressed on blood cells |
| MHC I expression | codominant expression moves each cell displays 6 peptides |
| MHC II structure | heterodimer of 34000 Da alpha chain and 29000 Da beta chain each folds into 2 domains |
| MHC II binding cleft | formed by alpha and beta chain |
| MHC II distribution | b cells, macrophages and dendritic cells display |
| MHC II expression | also expressed codominantly, 12 different in humans |
| irreversible MHC | allows for long term display of complexes |
| antigen dependent MHC | loss of peptide from b cells halts MHC presentation at cell surface |
| self presentation MHC | self peptides can be presented mechanism for grafting |
| antigen processing | involves protein degradation and formation of peptide:MHC complex |
| antigen presentation | involves transport of peptide:MHC complexes to cell membrane of APCs |
| professional APCs | cells that express peptide:MHC I complexes and can provide costimulatory signals includes macrophages, b cells and dendrictic cells |
| nonprofessional APCs | express peptide:MHC I complexes and can provide costimulatory signals includes fibroblasts, glia, thymic epithelial, acinor, pancreatic beta and vascular epithelial cells |
| cytosolic pathway | degrades proteins originiating inside cell |
| TAP | transporter associated with antigen processing |
| endocytic pathway | degrades antigens that originate outside the cell |
| 3 signals of t cell activation | antigen recognition, costimulatory molecules, pre signal adhesion |
| CD2 | cell adhesion molecule found on surface of T cells and NK cells |
| LFA-3 | cell adhesion molecule expressed on APCs, particularly macrophages |
| LFA-1 | cell adhesion molecule found on lymphocytes and plays key role in emigration |
| ICAM-1 | cell adhesion molecule expressed on APCs |
| serial tiggering | each peptide:MHC complex consequentially engaged with up to 200 TCRs |
| B7 | proliferatory membrane protein found on activated APCs |
| CD28 | protein expressed on T cells that provides cotsimulatory signals |
| CD22 | sugar binding transmembrane potential binds to sialic acid and inhibits B cell receptors signalling |
| CD45R | protein tyrosin phosphate family expressed on B cells and some T cells |
| AP-70 | normally expressed near surface membrane of T cells |
| Fyn | tyrosine kinase, involved in regulation of cell morphology regulaton |
| Lck | tyrosine kinase in t cells, associated with cytoplasmic tails of CD4/8 coreceptors |
| IL-2 | promotes proliferation of differentiation of T cells into effector and memory T cells |
| endocytic pathway antigen | exogenous |
| endocytic pathway MHC | class 2 |
| endocytic pathway recognized | CD4+ helper t cells |
| endocytic pathway presented by | professional APCs |
| endocytic pathway type of response | humoral |
| cytosolic pathway antigen | endogenous |
| cytosolic pathway MHC | class 1 |
| cytosolic pathway recognized | CD8+ cytotoxic T cells |
| cytosolic pathway presented by | nucleated cells |
| cytosolic pathway type of response | cell mediated |
Created by:
gfquinn0
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