Term
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Definition
| Protein produced in response to an immunogen that possesses the unique property of being able to specifically bind to the immunogen that stimulated its formation |
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Term
| Define immunoglobulin (Ig) |
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Definition
| Globular glycoprotein composed of two identical heavy chains (H) and two identical light chains (L) that may function as an antibody. |
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Term
| What are the two key qualities of antibody molecules? |
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Definition
1. Specificity- a singly Ab will be very specific
2. Diversity- an individual has thousands of different antibodies |
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Term
| Give some examples of secondary activities of antibodies |
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Definition
| The ability to activate complement, to be actively transported across the placental barrier into the fetal circulation, and to be secreted and persist in the external secretions of the body |
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Term
| Are antibodies found in all animals? |
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Definition
No, only vertebrates
The "higher" the animal, generally the more complex the spectrum of antibodies |
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Term
| What macromolecule(s) are human antibodies composed of? |
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Definition
| Antibodies are glycoproteins (82-96% polypeptide & 4-18% carbohydrate) |
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Term
| What is the gamma globulin fraction? |
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Definition
The fraction of blood plasma that contains the various immunoglobulin classes
Reflects the immunologic history of the individual |
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Term
| Where can human antibodies be found? |
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Definition
1. Plasma
2. Extravascular fluid
3. Exocrine secretions
4. Surface of B-lymphocytes |
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Term
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Definition
Structurally homogeneous complete or partial immunoglobulins synthesized by a single clone of malignant plasma cells.
These immunoglobulins are valuable in the study of antibody structure. |
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Term
| What is a typical molecular weight of an Ig monomer? |
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Definition
| Molecular Weight of 150,000 - 190,000 varying primarily with carbohydrate content and differences in the peptide chain length in the hinge region of the heavy chains |
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Term
On an immunoglobulin, where is the light chain?
Where is the heavy chain?
Where are the variable/constant regions?
(Diagram on back) |
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Definition
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Term
| Define the hypervariable regions |
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Definition
| 3 sequences of 9-12 amino acids in each VL and VH. These are also called the complementary-determining regions (CDR); these portions of the molecule comprise most of the antigen-binding site |
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Term
| What is the term for the relatively invariant regions between the hypervariable regions? |
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Definition
| The relatively invariant regions between the hypervariable regions are called framework regions. |
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Term
| What regions form the antigen binding site? |
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Definition
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Term
| What sort of bonds/interactions attach antigen and antibody? |
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Definition
| NOT covalent. The bonds are reversible- hydrogen bonds, ionic bonds, hydrophobic interactions, and Van der Waals interactions. |
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Term
| Do constant regions have the same amino acid sequence between different Ig molecules? |
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Definition
Very similar, but not completely identical
Differences provide the basis for classification between IgG/A/M/E/D |
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Term
| How many amino acids and/or sugar residues can the antigen binding site accomodate? |
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Definition
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Term
| What are the names of the light chain domains? |
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Definition
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Term
| What are the names of the heavy chain domains? |
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Definition
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Term
| What is the hinge region? |
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Definition
| The relatively flexible region between CH1 and CH2 which provides the antigen-binding arms some freedom of motion and is exposed to enzymes and other chemicals. |
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Term
| What are the products of adding Papain to an Ig? |
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Definition
| Production of 2 Fab and 1 Fc |
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Term
| What are the products of adding Pepsin to an Ig? |
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Definition
| 1 F(ab'2) and small peptides |
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Term
What does an Ig look like after papain cleavage?
What does an Ig look like after pepsin cleavage? |
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Definition
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Term
| What is Digibind? How is it made? |
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Definition
Treatment of digoxin intoxication that works by binding molecules of digoxin.
It is made by immunizing sheep with digoxin hapten. Sheep antibodies produced are then papain-digested and the Fab fragments are purified by affinity chromatography. |
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Term
| Why are F(ab)'2 fragments used in overdose treatments (instead of an entire antibody or a Fab fragment)? |
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Definition
-Better at penetrating tumors and tissue than an intact antibody
-Better at inducing apoptosis than Fab (because an F(ab)'2 fragment can crosslink) |
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Term
| What is antibody cross-linking? |
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Definition
| When the two arms of an Ig bind different cells, changing it to a T-shape, allowing for precipitation and agglutination |
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Term
| What is the specificity of an IgG? What is the specificity of an IgM? |
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Definition
| Specificity of a single antibody is always 1 |
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Term
| What is the valency of an IgG? What is the valency of an IgM? |
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Definition
IgG- Divalent
IgM- Decavalent |
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Term
| Which antibodies can pass the placenta |
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Definition
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