Term
| What antibodies do naive B cells express? |
|
Definition
| IgM and IgD (slide 30 of this powerpoint) |
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Term
| For IgG, how big is the heavy chain? the light chain? |
|
Definition
| 50, 25 (150 total for antibody) |
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Term
| Where is the N terminus of the heavy chain? the C terminus? |
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Definition
| N terminus is on the variable region, c terminus is on the constant region |
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Term
| Why is it advantageous to have a "hinge region" on an antibody |
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Definition
| hinge region allows flexibility so antibody can bind to a diverse arrangement of two antigens |
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Term
| How many segments make up the C domain? |
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Definition
| 3-4 depending on the specific isotype (3 in IgG, IgD, IgA; 4 in IgM and IgE) |
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|
Term
| How many globular regions and how many beta sheets in Ig? |
|
Definition
| three globular regions and 2 beta sheets |
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Term
| How are the beta sheets held together in an Ig? |
|
Definition
| hydrophobic interactions and disulfide bonds |
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Term
| Heavy chain of IgG is known as _____. |
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Definition
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Term
| Heavy chain of IgM is known as ______. |
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Definition
|
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Term
| Heavy chain of IgD is known as ____. |
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Definition
|
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Term
| Heavy chain of IgA is known as ____. |
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Definition
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Term
| Heavy chain of IgE is known as ___. |
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Definition
|
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Term
| Name the two isotypes of light chains. |
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Definition
|
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Term
| Name the class of antibodies that are tetramers. |
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Definition
|
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Term
| Name the class of antibodies that are dimers. |
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Definition
|
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Term
| Hypervariable regions are also called ___________ regions. |
|
Definition
| complmentarity determining regions (CDR) |
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|
Term
| What is a multivalent antigen? |
|
Definition
| when an antigen contains more than one epitope or more than one copy of an epitope |
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Term
| What are chimeric monoclonal antibodies? |
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Definition
| use a mouse V region with a human C region to create an antibody that only recognizes one epitope (monoclonal). Ex. Riftuximab--anti CD 20 (tx for non-Hodgin B cell lymphoma) |
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|
Term
| What are humanized monoclonal antibodies? |
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Definition
| when a mouse CDR is combined with a humna Ig to make an antibody specific to one epitope. Ex- Omalizumab used as antihuman IgE for allergies |
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Term
| Adalimumab (an anti TNF alpha medication) is a _______ ________ antibody. |
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Definition
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Term
| Which parts of the antibody are transcribed without gene rearrangment? |
|
Definition
| the leader peptide and the C region (the V region requires Gene rearrangment) |
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|
Term
| What is somatic recombination? |
|
Definition
| When the V and J segments are cut and spliced by DNA recombination in "somatic" B cells. |
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Term
| How is somatic recombination different in light chains than in heavy chains? |
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Definition
| light chains require a single recombination (VL +JL) while heavy chains require 2 recombinations (D + JH = DJ + VH) |
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Term
| In somatic recombination of heavy chains, what prevents V combining with J first instead of combining with D then J? |
|
Definition
| recombination signal sequences that flank segments |
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Term
| What is the enzyme responsible for insertional diversity? |
|
Definition
| Terminal deoxynucleotidyltransferase (Tdt) |
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|
Term
| RAG enzyme stands for _______. |
|
Definition
| Recombination acting genes |
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|
Term
| What is junctional diversity? |
|
Definition
| When the variable segments (V, D or J) are joined together by nonhomologous end joining and the ends are modified and nucleotides are randomly added |
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|
Term
| What are P nucleotides? What are N nucleotides? |
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Definition
| P nucleotides are the palindromic nucleotides. The N nucleotides are the Non-templated nucleotides (nucleotides added by the enzyme terminal deoxynucleotidyl transferase) |
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|
Term
| What is the function of RAG? |
|
Definition
| the associate with other enzymes to form V(D)J recombinase |
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Term
| Is the isotype of an antibody determined by the heavy chain or the light chain? |
|
Definition
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Term
| How are both IgM and IgD antibodies with the same specificity made in naive B cells? |
|
Definition
| the VDJ region is before the IgM and the IgD region. After VDJ is transcribed, there is no strong stop signal so IgM and IgD exons are transcribed and attached to VDJ via alternative splicing |
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|
Term
| Do naive B cells make more IgM or more IgD? |
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Definition
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Term
| The three types of diversity of antibodies that occur before cell encounters an antigen are... |
|
Definition
| combinatorial (combination of VDJ segments), Junctional (P nucleotides), Insertional (N nucleotides) |
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Term
| What allows some IgM to be secreted and other IgM to be membrane bound? |
|
Definition
| different RNA processing of the antibody tail. MC tail is hydrophobic and transmembrane. SH tail is hydrophilic so membrane is secreted. |
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Term
| What is the difference between affinity and avidity? |
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Definition
| Affinity is the strength of binding at one site. Avidity is the overall strength of binding at multiple sites |
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Term
| If IgM and IgA have the same affinity, will their avidity be the same? |
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Definition
| No. IgM is pentameric so it has five binding sites and therefore will have a higher avidity |
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Term
| Random, single mutations in the V region is termed ____. |
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Definition
|
|
Term
| Name the enzyme required for somatic hypermutation. |
|
Definition
| AID (activation-induced cytidine deaminase) |
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|
Term
| Where on the antibody do somatic hypermutations preferentially occur? |
|
Definition
|
|
Term
| What is affinity maturation? |
|
Definition
| When higher affinity antibodies are made as the infection progresses |
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|
Term
| Why do we need different isotypes of antibodies? |
|
Definition
| because they serve different functions |
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|
Term
| Which antibody isotype performs most functions? |
|
Definition
|
|
Term
| Which antibody isotype is responsible for sensitization of mast cells? |
|
Definition
|
|
Term
| What are switch sequences, or switch regions? |
|
Definition
| highly repetitive sequences flanking the 5 prime side of C genes |
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Term
| How do B cells start making other isotypes of antibodies once they encounter an antigen? |
|
Definition
| The C genes for other antibodies are downstream from IgM and IgD. Before the different C genes (on the 5' end) are switch sequences or switch regions. AID joins together these switch regions and so the downstream antibody constant region is produced that can recognize the same antigen |
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|
Term
| What enzyme is required for isotype switching? |
|
Definition
| AID (activation-induced cytidine deaminase) function= deaminate cytosines into uracils so uracil-DNA-glycosylase (UNG) can remove the uracil |
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|
Term
| How many subclasses of IgG are there? |
|
Definition
|
|
Term
| Which antibody is the most abundant? |
|
Definition
|
|
Term
| Name the antibody isotype with no known purpose. |
|
Definition
|
|
Term
| How many sublcasses of IgA are there? |
|
Definition
|
|
Term
| What are the two possible phenotypes of hyper IgM syndrome? |
|
Definition
| 1) susceptibility to pryogenic and opportunistic infections 2) susceptibility to pyrogenic infections |
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Term
| Susceptibility to pyrogenic and opportunistic infections indicates defects in.. |
|
Definition
| CD40 and CD40 ligand genes |
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Term
| Susceptibility to pyrogenic infections indicates... |
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Definition
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|
Term
| How do B cells know when to "class switch" and go from making IgM to IgG? |
|
Definition
| cytokines released by T cells |
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