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64 Cards in this Set
- Front
- Back
What happens during phagocytic barriers? What proteins are involved the barriers?
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1. PRR (pattern recognition receptor) on the macophage binds with PAMP (pathogen-associated molecular pattern) on the bacteria. PRR does not binds to eukaryotic cells, it's specific to bacteria. Binding of PRR with PAMP induces engulfment.
2. Phagosome fuses with lysosome to form phagolysosome. Phagolysosome contains anti-bacterial enzymes. |
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what are the 5 mediators of Innate Immunity
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physical barriers
physiologic barriers phagocytic barriers inglammatory barriers complement |
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Ag binds to ____ or _____
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antibody or T cell receptor
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the surface peptide of Ag where Ab binds to
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Antigenic determinant or epitope
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function of hemogglutinin of influenza virus
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assist virus getting into cells
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5 classes of human Ig. What Ig structure is the class based on?
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A, D, E, G, M
constant region of the heavy chain |
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2 different families of light chain.
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kappa and lambda
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the function of J chain
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connect >2 Ig monomers together
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Which Ig form polymer?
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IgA dimer
IgM pentamer |
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antibodies exist in one of 3 physical states
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1. Integrated into the plasma cell membrane of a B cell acting as an antigen receptor. 2. Associated with Fc receptors on the surfaces of numerous cell types. 3. In a soluble form, dispersed in bodily fluids including serum and saliva.
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3 immunologically privileged sites, no immunological rx occur here
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brain, amniotic fluid, anterior lens capsule
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sites where IgG, dimeric IgA and IgE are found
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IgG: connective tissue, developing fetus
dimeric IgA: glandular tissue, digestive track, lungs IgE: epithelial/mucosal surfaces |
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predominant Ig in serum and secretion
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serum: IgG
secretion: dimeric IgA |
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effector functions of Ab
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simple Ag-Ab interactions
interactions with accessory cells interactions with accessory molecules |
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simple Ag-Ab interactions
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neutralization of virus, toxins, bacterial cells
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Fc-gamma are found on the surface on what cell types?
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mast cells, macrophages, eosinophills, NK cells, neutrophils
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dimeric IgA molecules are secreted by what types of cell?
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B cells and plasma cells
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phagocytosis can be carried out by what 4 cells?
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neutrophils, monocytes, macrophages and dendritic cells.
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opsonization
Which type of Ab mediate opsonization? |
get pathogens to be engulfed by phagocytic cells, by coating the Ag with Ab's.
IgG mediate opsonization. |
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what cell surface protein binds to IgA to facilitate its crossing epithelial cells to get into the gut lumen?
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poly-Ig receptors
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where does poly-Ig receptor binds to on IgA?
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J chain
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what's the function of secretory component on dimeric IgA?
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stabiliza dimeric IgA in harsh conditions
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secretory components are produced by what cell type?
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mucosal epithelial cells
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Antibody dependent cell-mediated cytotoxity (ADCC) involve which cells and which Ig? ADCC attachs both intra and extracellular pathogens.
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cells: eosinophils and NK
Ig: IgG (viral infection) and IgE (parasitic infection) |
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function of IgE
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involved in parasitic infection, allergic
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function of IgG
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protect the bodies against, virus, bacteria and fungi thru agglutinization, neutralization, opsonization and ADCC.
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C3a, C4a and C5a, proteolytic complement fragments, are capable of inducing what?
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inflammation
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C3b and C5a acts as
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opsonins by binding to specific receptors on the surface of phagocytic cells
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C5, C6, C7, C8, and C9 (terminal complement proteins)
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polymerize to form the membrane attach complex. This generates pores in the plasma membrane of the cell and lead to osmotic lysis.
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end results of classical pathways (functions of complements)
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1. opsonization and phagocytosis
2. stimulation of inflammatory rx 3. complement-mediated cytolysis |
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classical pathway are part of innate or acquired immunity?
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part of acquired immunity
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Mb-lectin and alternative pathways are innate or acquired immunity?
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innate immunity
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CD3, CD4, CD8 are found on T or B cells?
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T cells
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CD19 are found where
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B cells
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in the absence of interaction of T cell induced B cell differentiation, B cells differentiate into
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IgM producing B cells
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cytokine produced by T helper cell induce B cells to undergo clonal expansion and plasma differentiation to secret Ig. IFN-gamma, IL4, and TGF-beta (cytokines) induce B cells to secrete?
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IFN-y: IgG subclasses
IL-4: IgE TGF-b: IgA |
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skin graft rejection is mediated by T cells or B cells?
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T cells
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MHC Class I structure
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alpha (1-3), beta 2-microglulin
extension of alpha 3 is inserted into PM |
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MHC Class II structure
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alpha (1-2), beta (1-2)
alpha2 and beta2 are inserted into PM |
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what cells express MHC class I?
what cells express MHC class II? |
MHC class I: all nucleated cells
MHC class II: B cells, macrophages, dendritic cells, and activated T cells |
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in humans, MHC genes are referred to ____, located on chromosome _____, they are ____morphic.
MHC alleles are _____ expressed |
human lymphocyte antigen (HLA) genes
chromosome 6 polymorphic codominantly expressed |
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beta 2 microglobulin gene is encoded on chromosome ___
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chromosome 2, beta 2-microglobulin gene is part of the MHC Class I
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CD4+ helper T cells recognize peptides bound to Class ___ MHC molecules
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Class II MHC molecules
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CD8+ cytotoxic T cells recognize peptides bound to Class ___ molecuels
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Class I MHC molecuels
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professional Ag presenting cells are
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cells that have both MHC I and II, and they are dendritic cells, macrophages, B lymphocytes and activated T cells
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T cells only recognize proteins. T/F
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T
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Class II MHC pathway
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endocytosis of extracellular protein -> degradation of the protein -> binding of degraded protein and MHC II -> presentation of peptide-MHC II complex -> CD4 T cell recognition
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Class I MHC pathway
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Cytosolic foreign protein degraded by proteasome -> binding of MHC I with degraded peptide -> presentation of foreign peptide -> CD8 CTL cell recognition
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CD3 structure and function
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CD 3 molecules are complex of 4 different proteins, trasmembrane and cytoplasmic domains and they are always associated with TCR. The CD3 function is to amplify signal transduction from TCR.
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T cell antigen receptor (TCR) structure
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T cell Ag receptor is composed of 2 heterodimer chains: alpha and beta, have transmembrane and cytoplasmic domain, glycoprotein. There are variable and constant region. variable region make the amino terminal end and constant region make up the carboxyl terminal end.
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IL2 secreted by CD4 T cells bind to IL-2R on CD8 T cells
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clonal expansion of T cells. Differentiate into CD8 CTL cells and memory CD8 T cells
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perforin and granzymes
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they are effector molecules of cellular immunity (CTL T cells)
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perforin
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creates pores on the PM of effected cells
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granzymes
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cleave caspases and activate them
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Subsets of T helper cells
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Th1 cell and Th2 cell
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functions of Th1 and Th2 cells
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Th1 cells: activates macrophages, induce B cells to produce opsonizing Ab's
Th2 cells: activate B cells predominantly to make neutralizing Ab, has effects on macrophages |
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cytokines produced by Th2 subset
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IL4 and IL5, and they activates IgE for antiparasitic activity
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IL10
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secreted by Th2, suppresses macrophage activation or Th1 activation of macriphages
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IFN-y
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secreted by Th1 subset for viral infection. macrophage activation, induces B cells to produce opsonizing Ab.
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In order for TCR activation to happen, TCR recognize two parts on the MHC molecule
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1. polymorphic residue on the MHC molecule
2. presented foreign peptide. |
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2 step process of T cell activation.
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1. a primary signal derived from the binding of the peptide:MHC complex by the T cell receptor.
2. secondary signals that are provided by co-stimulatory molecules expressed on the the surface of the antigen presenting cell as well as cytokines. |
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cytokines produced by Th1 (subset of helper cell)
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IFN-y
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cytokines produced by Th2 (subset of helper cell)
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IL-4, IL-5, IL10
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tumor cell rejection is mediated by
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cytotoxic T cells
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