Term
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Definition
molecular structures recognized by cells of adaptive immune system
substance that binds to the products of the adaptive immune response (Ab, T cell) (antigenic). |
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Term
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Definition
Native structure of protein or polysaccharide
Area of recognition on an Ag - epitope
Linear
Conformational |
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Term
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Definition
| Processed peptide that binds to MHC on APC (antigen presenting cell) |
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Term
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Definition
| substance that induces the adaptive immune response (immunogenic) |
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Term
Immunogenic is always antigenic
Antigenic is not always immunogenic
*Memorize this concept |
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Definition
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Term
| B cell recognizes specific Ag via |
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Definition
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Term
Over view of B cell response in secondary lymphoid tissues
(4 main steps) |
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Definition
1. B cell recognizes specific Ag via B cell receptor (BCR)
2. B cell activation
2a. B cell interact with CD4 Th cells
via Immunological synapse, lymphokines
3. B cell proliferation
differentiation
3a. Undergo somatic hypermutation
Ag class switch in LN.
Become plasma cells that produce
(IgG, IgA or IgE)
3b. IgM plasma cell
4. Generation of memory B cell |
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Term
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Definition
Y shaped molecule.
2 identical sub-units (light and heavy chain) linked together by disulfide bond
2 light chains, 2 heavy chains
Flexible hinge region |
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Term
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Definition
1. Antigen binding site – N-terminal- variable region.
Genetically diverse
Each individual Ab recognize a specific Ag.(clonal)
2. Effector site – C-terminal, - constant region
Interacts other cells and soluble proteins to perform Ab function.
Effector cells (macrophage, neutrophil, NK cell etc.
Effector molecules (complements) |
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Term
| variable domain (VL or VH) |
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Definition
| The first N-terminus domain. Ag binding domain. |
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Term
| constant domains (CL, CH1-3) |
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Definition
| C – terminus domains. Less variable. |
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Term
| The flexible region between CH1 and CH2 is |
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Definition
| the hinge region (disulfide bond) |
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Term
| Molecules with structure similar to Ig (repeated domain) is belong to... |
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Definition
| the immunoglobulin super family) (remember ICAM-1?) |
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Term
| Two forms of Immunoglobulin |
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Definition
1. Membrane bound Ig – B cell receptor (BCR)
2. Secreted Ig – Antibody (Ab). |
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Term
| Membrane bound Ig – B cell receptor (BCR) |
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Definition
Extra transmembrane region for membrane anchoring.
For binding specific Ag and initiating B cell activation.
Naïve B cell has BCR but does not produce secreted Ab. |
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Term
| Secreted Ig – Antibody (Ab). |
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Definition
No-transmembrane region
Produced by antigen activated and differentiated B cells – plasma blasts and plasma cells.
Plasma cell (terminally differentiated B cell) produces Ab but does not express BCR on cell surface |
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Term
Structure of Ig domain
L chain as example |
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Definition
A domain consists of 2 beta sheets hold together by disulfide bond and forms beta barrel.
Variable domain has bigger beta sheet with extra loops.
Some loops in VARIABLE domain are the actual Ag binding areas. |
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Term
| The aa sequence viability in V region is.. |
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Definition
| ....not evenly distributed |
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Term
| Hyper variable region (HV) |
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Definition
| Sequences in some loops at the tip of the V domain that are highly variable. contributes to antibody diversity and antigen binding specificity |
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Term
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Definition
Regions between hyper variable region (HV) that are relatively constant.
FR corresponds to the beta sheet and other loops. |
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Term
| Both light and heavy variable domains have __ HV and __ FR regions |
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Definition
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Term
| Antibody’s antigen binding site is formed by variable regions from... |
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Definition
| both hyper variable region (HV) of light and heavy chains from V region (VL and VH) |
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Term
| Antibody diversity is determined by... |
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Definition
| HV from both light and heavy chains. |
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Term
| The HV regions is also called |
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Definition
| complementarity–determining-region (CDR). |
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Term
| Ig can be enzymetically cleaved into: |
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Definition
Fab (fragment antigen binding) or F(ab’)2
Fc (fregment crystalizable). – confer the binding to effector molecules or cells. |
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Term
| Fab and F(ab’)2 can bind to antigen without _____ function |
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Definition
| effector function (such as opsonin to induce phagocytosis, antibody-dependent cell-mediated cytotoxity (ADCC), and complement activation.) |
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Term
| IgM is secreted as a _____ connected by ______ and _____ |
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Definition
| IgM secreted as pentamer connected by disulfide bond and J chain (joining chain) |
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Term
| 3 things IgM pentamer does for antigens: |
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Definition
| increases Ag binding site, Ag binding strength (avidity), and better complement activation. |
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Term
| Which Ig can be either monomeric or dimeric? |
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Definition
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Term
| Dimeric IgA is also called .... |
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Definition
| ...secretory IgA since it can be transcytosed through mucosal epithelial cells into the musocal surface. |
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Term
| Monomeric IgA are mainly found where? |
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Definition
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Term
| antibody (immunoglobulin) repertoire |
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Definition
| The total number of antibody (immunoglobulin) specificity |
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Term
| Each B cell produces one clone of antibody that recognizes only one specific |
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Definition
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Term
| Antibody repertoire is made of ... |
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Definition
| the combined antibody specificity from all B cells in an individual. |
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Term
| Antibody gene in B cell undergo |
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Definition
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Term
| Light chain V domain is made of.... |
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Definition
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Term
| Light chain V region consists of a ____ segment and a ____ segment |
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Definition
1. larger (~100 aa) variable (V) gene segment
2.small (~10 aa) joining (J) gene segment. |
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Term
| heavy chain V region consists of ___,___, and ___ segment |
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Definition
1. variable V segment
2. diversity D segment
3. joining J segment |
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Term
| Which chain and which region of immunoglobulin rearranges first? |
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Definition
| H chain V region genes are rearranged first. |
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Term
| VH (variable heavy) domain is made up of.... |
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Definition
| VDJ segments. After D-J recombination, V segment rearranges with the D-J to form VDJ. |
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Term
| Are L chain V region genes rearranged before or after H chain V region? |
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Definition
| L chain V region genes are rearranged AFTER H chain V region. |
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Term
| VL (variable light) domain is made up of... |
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Definition
| VJ segments. One V and one J segment out of many are rearranged (V-J-recombination) |
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Term
| VL (variable light) domain is made up of... |
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Definition
| VJ segments. One V and one J segment out of many are rearranged (V-J-recombination) |
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Term
| recombination signal sequences (RSS) |
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Definition
| sequences that flank V,D, J gene segments. RSS arrangement: heptamer – spacer – nonamer. Heptamer is always adjacent to coding sequence. |
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Term
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Definition
| 23 base-pair spacer, 12 base-pair spacer |
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Term
| Immunoglobulin gene rearrangement occurs only between segments with RSS of |
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Definition
| 12 spacer and 23 spacer (12/23 rule). This rule ensure rearrangement only between V(D)J. |
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Term
| Ig gene rearrangement is a multiple step process involving lymphocyte specific recombinases.... |
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Definition
| RAG-1 and RAG-2 (recombinant activating gene) |
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Term
1. RAG1/RAG2 complex binds to RSS of __ and __ segments.
2. Afterwards, what is the process that RAG1/RAG2 follows? |
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Definition
1. V and J
2.
a) brings two RSS together
b) cleave at the end of heptamer
c) loop out sequence between two RSSs |
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Term
| Cellular DNA repair enzymes join DNA ends to create.... |
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Definition
| signal joint and coding joint. |
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Term
| Cellular DNA repair enzymes are involved for gene rearrangement for.... |
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Definition
| ....both immunoglobulin and T cell receptor. |
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Term
| severe combined immune deficiency (SCID) |
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Definition
| When deficiency in genes involving in the gene rearrangement results in the deficiency in both B cells and T cells |
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Term
| After Ig gene rearrangement, do B cells have MORE or LESS DNA than cells with germline DNA? |
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Definition
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Term
| What additional immunoglobulin gene can be created at the coding joint? |
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Definition
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Term
| What type of nucleotides are added to the VJ or VDJ junction sites? |
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Definition
| P-nucleotides and N-nucleotides |
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Term
1. P-nucleotides (palindromic nucleotides)
2. N-nucleotides (Nontemplated nucleotides) |
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Definition
1. generated by open hairpins at a random site
2. generated by randomly adding nucleotides by TdT |
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Term
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Definition
| The diversity created at junction site due to additional nucleotides, it significantly increases the total diversity |
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Term
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Definition
| terminal deoxynucleotidyl transferase |
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Term
| The immunoglobulin gene diversity is generated by 3 ways during rearrangement: |
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Definition
1. V region genetic rearrangements (recombination) – combinatorial diversity
2. At V-D-J or V-J joints - Junctional diversity
3. Ag binding site is formed by combining VL and VH. |
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Term
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Definition
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Term
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Definition
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Term
| Once V(D)J rearrangement is completed, will V region undergo further rearrangement? |
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Definition
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Term
| After V region rearrangement the light and heavy chains of Ig DNA are organized as: |
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Definition
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Term
| 4 Steps that occur during immunoglobulin expression |
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Definition
1. Primary RNA for H or L chain is transcribed.
2. Processed mRNA with removed introns, added poly A tail is ready to be translated to Ig L or H chain proteins.
3. L (leader peptide) is cleaved after translation,
4. Disulfide bond is formed to hold 2 H/L chains together |
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Term
| Alternative RNA processing produces |
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Definition
| IgM and IgD mRNA – NOT DNA rearrangement |
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Term
| Naïve B cells express which Igs? |
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Definition
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Term
| Primary RNA transcripts for H chain contains C region for... |
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Definition
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Term
| Which two Igs are the only Igs that can be co-expressed? |
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Definition
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Term
1. MC stands for....
2. pAmm or pAdm stands for...
2. SC stands for.... |
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Definition
1. membrane coding
2. site for cleavage and polyadenylation
3. secretion code |
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Term
| Each Ig H chain (IgM for example) has ___ sequence for transmembrane region of membrane bound IgM and ___ sequence for secreted IgM |
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Definition
| MC sequence and SC sequence |
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Term
| Primary IgM RNA transcript contains |
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Definition
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Term
| Alternative RNA processing cleaves at ____ or ____ and produces mRNA for either ____ IgM or _____ IgM |
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Definition
| Alternative RNA processing cleaves at either pAmm and pAm and produces mRNA for either membrane IgM or secreted IgM. |
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Term
| There are five isotypes of antibody, which are determined by constant regions of ____ |
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Definition
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Term
| Each isotype of Ab have distinctive.... |
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Definition
| ...tissue distribution and functions along with antibody functions |
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Term
| IgM is primarily in found____, with one exception, which is.... |
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Definition
| Found mainly in blood circulation and can exit blood vessels to enter tissues during inflammation |
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Term
| Which two Igs are both found in blood circulation and tissue interstitial fluids? |
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Definition
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Term
| Which Ig can be transported from placenta to fetus? |
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Definition
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Term
| Which Ig is secreted by B cells in mucosal tissues transcytosed through epithelial cells to ____ surface and be secreted from mammary gland to milk? |
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Definition
| Dimeric IgA Dimeric IgA is secreted by B cells in mucosal tissues and can be transcytosed through epithelial cells to MUCOSAL surface and be secreted from mammary gland to milk.. |
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Term
| Which Ig binds tightly to FceRI and where are these FceRI receptors found? (found on three types of cells) |
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Definition
| IgE binds tightly to FceRI (Fc receptor for IgE) on MAST CELLS, BASOPHILS, and ACTIVATED EOSINOPHILS |
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Term
| Where are these mast cell, basophils, or activated eosinophils located when IgE binds tightly to their FceRI receptors? |
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Definition
1. mast cells: distribute in connective tissue under epithelial cell layer (skin, mucosal surface)
2. basophils: blood circulation
3. activated eosinophils: mucosal surface |
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Term
| Fc receptor FcRn facilitates .... |
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Definition
| ...IgG entry to tissue interstitial and placenta |
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Term
| IgG transport through endothelial cells is aimed by... |
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Definition
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Term
| FcRn is a ____ molecule that protects IgG from ___ and increases IgG _____ |
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Definition
| FcRn is a MHC class I like molecule that protects IgG from degradation and increases IgG half-life |
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Term
| Dimeric IgA is transported to mucosal surface by ... |
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Definition
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Term
| Poly-Ig receptor on basolateral membrane of mucosal epithelial cells binds ___ chain of which Ig and then transports that particular Ig to the apical surface of the cell. |
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Definition
| Poly-Ig receptor on basolateral membrane of mucosal epithelial cells binds J chain of dimeric IgA (also called secretory IgA, sIgA) and transports sIgA to the apical surface of the cell. |
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Term
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Definition
| Portion of the receptor remaining on sIgA after poly-Ig receptor is cleaved |
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Term
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Definition
| ....the mucosal surfaces of the body by resisting the proteases on the musosal surfaces including intestinal surface. |
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Term
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Definition
| part of antigen that antibody binds, also called antigenic determinant |
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Term
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Definition
a complex molecule or a whole pathogen has many epitopes on it.
1. Multiple distinct epitopes – binding of many different Ab
2. Repeated epitopes. – multiple identical molecules or molecular structures on pathogen such as polysaccharides which bind to the same Ab molecules |
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Term
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Definition
| Linear sequence, epitope will not disappear when protein is denatured. |
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Term
| Conformational/discontinuous epitope: |
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Definition
| Epitope will disappear when protein is denatured. |
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Term
| Three modes of neutralization |
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Definition
1. Ab binds to virus surface proteins and blocks virus attachment and entry to cells – kills virus by terminate virus replication cycle and prevents virus from continuous spreading between cells.
2. Ab binds to bacteria surface protein and prevents bacteria attachment to cell – prevents invasion.
3. Ab binds to toxin and prevents toxin binding to cellular receptor – abrogates toxin effects. |
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Term
| Which two Igs have the strongest neutralizing activity? |
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Definition
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Term
| Can Ab neutralize without Fc portion? |
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Definition
| Yes, and Ab neutralizing activities have been used to block bio-active molecules in research and treatments. |
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Term
Antibody effector functions:
(there are five of them) |
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Definition
1. Neutralization
2. complement activation
3. opsonization
4. Antibody-dependent cell-mediated cytotoxicity - (ADCC)
5. sensitizing of mast cells - IgE |
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Term
| Soluble pentameric IgM is in ___ form that can not activate classic pathway of complement activation. |
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Definition
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Term
| IgM binding to Ag induces conformation change to ____ form that can activate complement |
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Definition
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Term
| _____are required for complement activation. (Single Ag bound IgG can not activate complement) |
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Definition
| Multiple Ag bound IgG (at least 2) |
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Term
| The binding of what two molecules causes an immune complex in blood circulation that can further activate complements resulting in C3b binding in immune complex? |
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Definition
| Antibody (IgG) binding of soluble Ag such as toxin or pathogen fragments |
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Term
| Which receptor on erythrocytes binds C3b on the immune complex and brings the complex to liver or spleen? |
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Definition
| Complement receptor 1 (CR1) |
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Term
| The mechanism of immune complex removal: |
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Definition
| Macrophages, which have CR1 and Fc receptor can remove immune complexes from erythrocytes and digest them |
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Term
| Failure to clear the immune complex will result in.... |
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Definition
| ...deposit of large amount of immune complex on basal membrane of small blood vessel in organs such as kidney, causing diseases such as nephritis. |
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Term
| During opsonization, IgG1 and IgG3 bind to pathogens and interact with... |
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Definition
| ...Fc receptor (FcyRI) on phagocytes. |
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Term
| Which Ig has very little opsonization activity? |
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Definition
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Term
| During antibody-dependent cell-mediated cytotoxicity, which Igs bind to antigens expressed on surface of target cell? |
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Definition
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Term
| During antibody-dependent cell-mediated cytotoxicity, Fc portion of IgG interacts with which Fc receptor on NK cell? |
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Definition
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Term
| IgE binds to high affinity FceRI on.... |
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Definition
| mast cells, basophils and activated eosinophils |
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Term
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Definition
| IgE on cell surface will bind to parasites and trigger mast cells and others to release granule contents |
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Term
| Granules of mast cell, basophil and eosinophil contain histamine and other inflammatory mediators that cause .... |
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Definition
| smooth muscle contraction, blood vessel permeability increase that function to attack and expel parasites from body. |
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Term
Describe IgG1 in the following:
1. Hinge region flexibility
2. Susceptible to proteolysis
3. Activate complement
4. Specific functions |
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Definition
1. intermediate
2. low
3. good
4. abundant, general purpose IgG |
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Term
Describe IgG2 in the following:
1. Hinge region flexibility
2. Susceptible to proteolysis
3. Activate complement
4. Specific functions |
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Definition
1. low, rigid
2. low
3. OK
4. specific for repeat epitope on bacterial polysaccharide |
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Term
Describe IgG3 in the following:
1. Hinge region flexibility
2. Susceptible to proteolysis
3. Activate complement
4. Specific functions |
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Definition
1. high
2. high
3. very good
4. better Ab cross-linking, good for COMPLEMENT activation |
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Term
Describe IgG4 in the following:
1. Hinge region flexibility
2. Susceptible to proteolysis
3. Activate complement
4. Specific functions |
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Definition
1. intermediate
2. low
3. poor
4. antagonize IgE, anti-inflammatory and anti-allergic, NO complement activation |
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Term
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Definition
| When IgG4 switch H and L chain |
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Term
| FcyRI: Binds to which Ig and what function does it have? |
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Definition
1. IgG1, 3
2. Activate phagocytes |
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Term
| FcyRIIB1: Binds to which Ig and what function does it have? |
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Definition
1. IgG1, 3
2. Inhibit naïve B cell activation |
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Term
| FcyRIII: Binds to which Ig and what function does it have? |
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Definition
1. IgG1, 3
2. Activating NK cell, mediate ADCC |
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Term
| FceRI: Binds to which Ig and what function does it have? |
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Definition
1. IgE
2. Bind IgE to the surfaces of mast cells, basophil, activated eosinophil and sensitize them. Activate these cells for degranulation during parasitic infection and allergic reaction. |
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Term
| FcaRI: Binds to which Ig and what function does it have? |
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Definition
1. IgA
2. Fc receptor for IgA |
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Term
| FcRn: Binds to which Ig and what function does it have? |
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Definition
1. IgG
2. Bind to IgG for transporting through endothelial cells and placenta – not a real Fc receptor |
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Term
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Definition
| membrane bound immunoglobulin (Ig) that recognizes specific antigen. |
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Term
| BCR associates with ___ and ___, which are the signal transduction molecules for BCR. |
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Definition
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Term
|
Definition
| Membrane Ig + Iga and Igb |
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Term
1. Iga and Igb extracellular domains
2. Iga and Igb cytoplasmic domain |
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Definition
1. Iga and Igb extracellular domains are Ig like and are linked by a disulfide bond.
2. Iga and Igb cytoplasmic domain each contains an immunoreceptor tyrosine-based activation motifs (ITAM), which is important in BCR signal transduction after Ag binding |
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Term
| B cell co-receptor consists of: (3 things) |
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Definition
1. CR2 (CD21) binding to iC3b or C3d on pathogen.
2. CD19: signal transduction, increase BCR signaling strength.
3. CD81: function unclear. |
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Term
| B cells have ___ that bind to C3b C3b and facilitate cleavage of C3b to ____ then to ____ by factor I |
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Definition
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Term
| How does B cell brings co-receptor complex close to BCR? |
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Definition
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Term
| B cell can be activated by cross-linking B cell receptors (BCR) with .... |
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Definition
| multivalent antigens on pathogen |
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Term
| BCR cross-linking activates.... |
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Definition
| Iga and Igb and B cell signal transduction pathway. |
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Term
| Signaling pathway 1 (BCR complex): |
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Definition
After Ag cross-linking of BCR...
Src-family protein tyrosine kinases such as Blk, Fyn or Lyn phosphorylate and activate ITAM of Igα and Igβ.
Activated ITAM recruits another tyrosine kinase Syk that binds to ITAM on Igβ. |
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Term
| Signaling pathway 2 (BCR co-receptor) |
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Definition
Binding CD21 (CR2) to C3d on Ag brings BCR co-receptor close to BCR.
BCR associated kinases phosphorylate and activate CD19.
Activated CD19 recruits Src family tyrosine kinase such as Lyn to activate signal transduction pathway.
BCR co-receptor mediated signaling pathway augments the B cell activation signaling pathway |
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Term
| Cognate CD4+ helper T cell |
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Definition
| CD4 T cell recognizes processed peptide Ag derived from the same protein Ag that B cell recognizes |
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Term
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Definition
| When CD4 T cell becomes activated (primed) by peptide Ag presented by DC. |
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Term
| To get help from T cell, B cell needs to... (2 things) |
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Definition
1. Present Ag to cognate T cell - B cell binds protein Ag via BCR, internalizes Ag, process protein Ag to be peptide Ag, and presents peptide Ag on MHC class II molecule to cognate CD4 T cell.
2. Establish physical contact with cognate helper T cell. |
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Term
| Basic steps of T cell help of B cell activation, proliferation and differentiation (6 steps) |
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Definition
1. CD4 helper T cell is activated by DC – primed helper T cells.
2. B cell receptor binds to protein Ag and activated
-BCR – Ag cross-linking,
-BCR co-receptor – C3d.
3. B cell internalizes protein Ag, processes peptide Ag and presents on MHC class II.
4. Primed cognate CD4 helper T cell recognize peptide Ag presented by B cell.
5. B cell establishes physical interaction with cognate T cell. Interaction augments B cell activation
6. T cell secrete cytokines to drive B cell activation, proliferation and differentiation to become Ab producing plasma cells. |
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Term
| immunological synapse (list what parts of B cell link to T cell during physical interaction) |
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Definition
Interaction of primed cognate CD4 T cells and B cells.
1. TCR--Ag + Class II MHC (Ag binding)
2. CD4--Class II MHC (T cell co-receptor)
3. CD40L--CD40 (Co-stimulatory molecules)
4. LFA-1--ICAM-1 (Adhesion molecules) |
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Term
| Cognate T cells secret cytokines IL4, IL5, and IL6. What are their functions? |
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Definition
IL4 – secreted early, for B cell activation, proliferation, differentiation.
IL5, IL6 – secreted later, for B cell differentiation, Ab production |
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Term
| Two signals for B cell activation to T dependent antigen: |
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Definition
1. Signal from antigen binding to BCR
2. Signal from Th cell and B cell interaction |
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Term
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Definition
| B cell can only receive help from helper T cell that recognizes the same antigen |
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Term
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Definition
small non-immunogenic molecules– can bind to Ig (antigenic) but can not elicit B cell and T cell responses
No antibody response |
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Term
| In order to produce antibody against hapten, hapten is fist linked to... |
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Definition
| protein carrier (hapten-carrier link). |
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Term
| DC processes the hapten-carrier linked molecule and presents peptide Ag derived from protein to stimulate T cell. This t-cell is now called a.. |
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Definition
| primed peptide Ag specific T cell |
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Term
| Hapten specific B cell can be activated by binding to... |
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Definition
| hapten on linked molecule. |
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Term
| Example of hapten and carrier phenomenon |
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Definition
| Linking bacteria polysaccharide with a protein carrier, tetanus toxoid, to elicite Ab against polysaccaride |
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Term
| Some of the pathogens are transported to secondary lymphoid tissues and taken up by specialized..... |
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Definition
| subcapsular sinus macrophage (SCS MΦ) and follicular DC (FDC). |
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Term
|
Definition
These cells trap pathogen Ag with complement receptor (CR1 or CR2) to complement components (C3b or C3d) on pathogens.
Displays bound antigen on their cell surface. |
|
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Term
|
Definition
| stromal cells or fibroblasts |
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Term
| How do FDC display complement coated pathogen and pathogen antigens for B cells to recognize? |
|
Definition
FDC use complement receptors.
CR1 – C3b
CR2 – iC3b, C3d. |
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Term
| Both activated T and B cells down regulate the expression of what chemokine and why? |
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Definition
S1P (sphingosine-1-phosphate) receptor.
S1P is the chemokine that attracts lymphocytes exit from LN. |
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Term
| After T and B cell interaction, these cells move to _____ to form _____ |
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Definition
| These cells then move to medullary cords for further proliferation to form primary focus |
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Term
| Some of B cells in primary focus differentiate to be... |
|
Definition
| plasmablasts, which are plasma cells that produce IgM as quick Ab response to pathogen. |
|
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Term
| Some of these B cells in primary focus move back to follicle with T cells to form... |
|
Definition
| germinal center (GC) or secondary focus. |
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Term
|
Definition
| Helper T cells in GC are called follicular helper T cells (Tfh) |
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Term
|
Definition
| Zone where resident resting B cells are pushed to the edge of GC |
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Term
Activated B cells in GC form dark and light zones.
B cells in dark zone are called centroblasts. What are the functions of centroblasts? |
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Definition
Large, intense proliferation.
Express low BCR
Undergo somatic hypermutation |
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Term
Activated B cells in GC form dark and light zones.
B cells in light zone are called centrocyte. What are the functions of centrocytes? |
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Definition
Small, low proliferation
BCR re-expression
Undergo affinity maturation |
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Term
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Definition
Ag activated B cells undergo mutation in V region during proliferation
Centroblasts undergo somatic hypermutation, move to light zone and become centrocytes. |
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Term
| somatic hypermutation is mediated by... |
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Definition
| activation-induced cytidine deaminase (AID), which is expressed only in proliferating B cells (centroblasts). |
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Term
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Definition
| AID randomly converts DNA cytosine to uracil, which can be converted to a random base by DNA repair enzymes, error-prone translesion DNA polymerase – induced random point mutation in V region. |
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Term
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Definition
| B cells undergo somatic hypermutation will be selected to survive based on Ig affinity to Ag. |
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Term
| Two places centrocyes migrate to after surviving Ig affinity test: |
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Definition
1. Some of high affinity centrocytes may differentiate to be plasma cells or memory B cells and exit LN.
2. Plasma cells enter bone marrow for long-term production of Ab. |
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Term
| tingible body macrophage. |
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Definition
| MΦs that ingest dead cells |
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Term
| Ab class switch is regulated by ____ and mediated by ___ and ____ |
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Definition
| Ab class switch is regulated by T cell cytokines and mediated by switch sequence (switch region) and AID (activation-induced cytidine deaminase). |
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Term
During Antibody class switch:
Switch sequence is located at |
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Definition
| 5’ of every C region except (Cd) - IgD so that IgD cannot be expressed alone |
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Term
During Antibody class switch:
Th1 response produces... |
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Definition
| IFN-g and stimulates IgG2a, IgG3 (mice), IgG1 (human) for better opsonization, phagocyte and NK cell activation against intracellular pathogen.. |
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Term
During Antibody class switch:
Th2 response produces... |
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Definition
| IL4, IL5 and TGF-b (transforming growth factor b)and stimulates IgG1, IgG2b (mice), IgG2, IgG4 (human) and IgA and IgE. |
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Term
BLIMP-1
What process does BLIMP-1 regulate? |
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Definition
transcriptional repressor that turns off genes that are responsible for B cell proliferation and differentiation.
BLIMP-1 functions:
Converting B cells to plasma cells that produce large amount of Ab. |
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Term
| Two places plasma cells migrate to: |
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Definition
1. medullary cords to be short-live plasma cells
2. bone marrow becoming long-lived plasma cells. |
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Term
| 3 things Plasma cells do: |
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Definition
1. down-regulate surface BCR
2. stop differentiation
3. produce large amount of secreted Ig - antibody. |
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Term
| Characteristics of Memory B cells: |
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Definition
1. Memory B cells have increased frequency to specific Ag (proliferation)
2. They have increased affinity (affinity maturation) to Ag
3. Produces more functional Ab (Ig class switch) |
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Term
| Memory B cells are found in... |
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Definition
| blood and secondary lymphoid tissues |
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Term
| Human memory B cells express special markers such as ____ and higher levels of ____ and other _____ for more efficient interaction with T cells |
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Definition
| Human memory B cells express special markers such as CD27 and higher levels of MHC class II and other co-stimulatory molecules for more efficient interaction with T cells.. |
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Term
| FcgRIIB1 has ITIM which stands for |
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Definition
| Immunoreceptor tyrosine-based inhibitory motif |
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Term
* Concept to remember:
Secondary antibody response is limited to antigen epitopes present during the primary B cell response because only memory B cells are re-activated. |
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Definition
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Term
| Antibody response to protein Ag requires ____ |
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Definition
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Term
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Definition
athymic
TI Ag can not be processed by B cells to present to T cell |
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Term
| early protective response |
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Definition
| Antibody response against TI antigen occurs rapidly after pathogen infection |
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Term
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Definition
1. TI-1 Ag:
Lipopolysaccharide (LPS) or bacteria CpG DNA, which has intrinsic function to directly activate B cells.
2. TI-2 Ag:
Polysaccharide on encapsulated bacteria – Streptococcus pneumoniae.
Form repeated units and activate Ag specific B cells by extensively cross-linking of BCR and co-receptors. |
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Term
| B cell response to thymus independent type 1 Ag (TI-1) |
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Definition
TI-1 Ag activates B cell by:
TI-1 Ag will:
1. Bind to BCR and co-receptor
2. Bind to Toll like receptors (TLRs) |
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Term
| No T cell help in TI-1 antibody response means: |
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Definition
1. Ab response to TI-1 Ag (especially to extracellular pathogen) develops more rapidly than Ab response to TD antigens.
2. lack of somatic hypermutation, no affinity maturation – low affinity Ab
3. little Ab class switch and memory response because no T cell help – mostly IgM Ab. |
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Term
| Two types of B cell responses to thymus independent type 1 Ag (TI-1) |
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Definition
1. In high concentration, TI-1 Ag can activate both Ag specific and non-specific B cells – polyclonal activation.
non-BCR receptors such as TLR mediate activation of Ag non-specific B cell.
2. In low concentration, (in most situations during early infection), TI-1 Ag activate only Ag specific B cells.
Antigen-specific BCR, co-receptor and TLR mediate this activation. |
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Term
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Definition
| polyclonal B cell activation, proliferation induced by TI-1 Ag |
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Term
| B cell response to thymus independent type 2 Ag (TI-2) |
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Definition
TI-2 Ag activates B cells by extensive cross-linking of BCR and co-receptors.
TI-2 Ag can activate B cell to produce IgM by cross-linking BCR. |
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Term
| B cell activating factor (BAFF) |
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Definition
| B cell activating factor (BAFF) from activated DC can drive B cell undergo class switching to produce IgG Ab |
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Term
| TI-2 Ag stimulates two unique subsets of B cells: |
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Definition
| B1 cells and marginal zone B cells (MZ B cells). |
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Term
| Regular B cells are also called |
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Definition
| follicle B cells or B2 cells |
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Term
| Common characteristics of B1 and MZ B cells: |
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Definition
1. limited Ag repertoire, low circulation, self renew, recognize common pathogen components such in polysaccharides of encapsulated bacteria.
2. These B cells react to pathogen infection and produce quick protective Ab response. |
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Term
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Definition
developed early in fetal liver
located in peritoneal cavity
produce Ab to protect body cavity |
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Term
| Marginal zone B cells (MZ B cell) |
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Definition
locate in marginal zone of spleen
produce Ab to bloodborne pathogens, . |
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Term
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Definition
| B1 cells contribute large portions of IgM in blood of non-immunized individual |
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Term
| B1 and MZ B cell are similar to innate immune cells because: |
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Definition
| B1 and MZ B cell are the cells that recognize common pathogen pattern instead of specific diverse Ag (similar to innate immune cells). |
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Term
| The polysaccharide capsule of encapsulated bacteria prevents: |
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Definition
| prevent phagocytosis and T cell response |
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Term
| young children are susceptible encapsulated bacterial infection because.... |
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Definition
| Functions of B1 and MZ B cell are not fully developed in young children and cannot develop Ab response to carbohydrate Ag |
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Term
| To vaccine these children without B1 and MZ B cells... |
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Definition
| polysaccharide Ag is conjugated to a carrier protein to induce T dependent Ab response to polysaccharides (hepton – carrier phenomenon). |
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Term
| Immunization is process of using _____ Ag stimulate the body immune response to produce antibody |
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Definition
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Term
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Definition
| strong antibody response stimulated by repeated injections of antigen (immunogen) |
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Term
| antiserum or hyperimmune serum |
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Definition
| Blood collected from these animals with high titers of antibody specific to the immunogen |
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Term
Polyclonal antibody production:
Subcutaneous (sc) and Intradermal (id) |
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Definition
| most efficient because many DCs can present Ag and induce adaptive immune response. |
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Term
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Definition
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Term
| Fuse spleen cell and myeloma cell using |
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Definition
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Term
De novo pathway
Salvage pathway |
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Definition
1. De novo pathway: able to synthesize its own nucleotides
2. Salvage pathway: dependent on HGPRT to form new nucleotides. This pathway is blocked by aminopterin found in HAT media. |
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Term
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Definition
| myeloma cells that obtain HGPRT and Ab genes from spleen cells |
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Term
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Definition
| common cloning method to make monoclonal antibodies |
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Term
| Transcriptional factors that regulate B cell development |
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Definition
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Term
| B cell development can be divided in several stages based on two things: |
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Definition
| Ig V region rearrangement and the generation of B cell receptor . |
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Term
Pick the right selection:
V region of H chain is rearranged (first/second) at (pro-B cell or pre-B cell stage) |
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Definition
| V region of H chain is rearranged first at pro-B cell stage. |
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Term
Pick the right selection:
V region of L chain is rearranged (first/second) at (pro-B cell or pre-B cell stage) |
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Definition
| V region of L chain is rearranged at pre-B cell stage. |
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