Nature of Antibodies Flashcards
Electrophoresis is at pH ___, immunoglobulins appear
primarily in the _____________
Electrophoresis is at pH 8.6, immunoglobulins appear
primarily in the gamma band
Combine with antigens on cellular surfaces and thereby cause the destruction of these cells either
1. _____________ (outside the
blood vessels within the mononuclear- phagocyte system, also known as _______________________) or
- ______________ (within blood vessels through the action of
________________)
Combine with antigens on cellular surfaces and thereby cause the destruction of these cells either
1. extravascular (outside the
blood vessels within the mononuclear- phagocyte system, also known as Reticular endothelial system (RES))) or
- intravascularly (within blood vessels through the action of
complement)
is the primarily organ where the antigens are destroyed
Spleen
THEORIES OF ANTIBODY DIVERSITY
- EHRLICH’S SIDE-CHAIN THEORY (SPECIFIC RECEPTOR)
- TEMPLATE THEORY (GENERAL RECEPTOR)
- CLONAL SELECTION
_____________ postulated that certain cells had specific surface receptors for antigen
Paul Ehrlich postulated that certain cells had specific surface receptors for antigen
Theory?
Occurred once antigen was introduced, it would select the cell with proper receptor, combination would take place and receptors would break off and enter the circulation as antibody molecules
EHRLICH’S SIDE-CHAIN THEORY (SPECIFIC RECEPTOR)
Who proposed the TEMPLATE THEORY (GENERAL RECEPTOR)?
Felix Haurowitz
Theory?
Antibody producing cells are capable of synthesizing a generalized type of antibody and when contact with an antigen occurs, the antigen serves as a mold or template and alters protein synthesis so hat antibody with specific fits is made
TEMPLATE THEORY (GENERAL RECEPTOR)
Most accepted theory for antibody diversity
CLONAL SELECTION
____________ and ________________ independently supported the idea of clonal selection process for antibody formation
Niels Jerne and Mcfarlane Burnet independently supported the idea of clonal selection process for antibody formation
Theory?
The key premise is that individual lymphocytes are genetically programmed to produce one type of immunoglobulin and that a specific antigen finds or selects those particular cells capable of responding to it, causing to proliferate
CLONAL SELECTION
BASIC STRUCTURE OF AN ANTIBODY
* Consist of 4 polypeptide chains
* Subdivided into _______________ and _______________
BASIC STRUCTURE OF AN ANTIBODY
* Consist of _polypeptide chains
* Subdivided into 2 Heavy chain (large chain) and 2 Light chain
(L chain)
________________ and ________________ worked on Immunoglobulin G (IgG)
Gerald Edelman and Rodney Porter worked on Immunoglobulin G (IgG)
A flexible Y-shaped molecule with four protein chains
MONOMER
What are the 2 identical light chains in monomer?
2 identical light chains- Kappa or Lambda chain
How many identical heavy chains in monomer?
2
two sections at the end of Y’s arm. Contains also the antigen binding sites (Fab) or the paratope. The Fab is identical on the same antibody, but vary from one antibody to another
VARIABLE REGION
T or F
The number of binding sites = the number of valences
T
- Stem of monomer and lower parts of Y arms
- Responsible for the type and antigen-antibody reaction that occurs
- Constant region of heavy chain differs from one antibody class to the other
- Structure serves as a basis for distinguishing the 5 different classes: IgG, IgA, IgM, IgD and IgE
CONSTANT REGION
FC stands for
Fragment Constant
T or F
All of the antibodies have the same Fc region
T
- All of the antibodies have the same Fc region
- Mainly the one attached to the B cells or T cells
- For complement fixation, skin fixation and placental transfer
- No capability to bind the antibody
FC (FRAGMENT CONSTANT) REGION
_______________________
* First approximately ____ amino acids at the amino-terminal
end
* The remaining amino acids can typically be divided up into two or three or more constant regions with very similar constant regions with very similar sequences, designated CH1, CH2, and CH3 (constant heavy chain 1,2,3)
VARIABLE DOMAIN
* First approximately 110 amino acids at the amino-terminal
end
* The remaining amino acids can typically be divided up into two or three or more constant regions with very similar constant regions with very similar sequences, designated CH1, CH2, and CH3 (constant heavy chain 1,2,3)
Refers to the heavy chain that determine the Ig class
Isotype
Minor variations of these sequences that are present in some individuals but not others
Allotype
- The aminoterminal ends of both L and H contain these regions, which are essential to the formation of the antigen-binding site
- variable portions of each chain are unique to a specific antibody molecule.
Idiotype
Possess both constant and variable regions, it is the same for all immunoglobulins
LIGHT CHAIN
- Kappa: contains ____ of the Ig
- Lambda: contains ____ of the Ig
o Ratio of K:L is ____
- Kappa: contains 65% of the Ig
- Lambda: contains 35% of the Ig
o Ratio of K:L is 2:1
Discovered through _________________ which are light
chains produced by a malignant plasma cell from the urine of Multiple Myeloma patients
Discovered through Bence Jones Proteins which are light
chains produced by a malignant plasma cell from the urine of Multiple Myeloma patients
_________________
* Connect heavy chains and heavy chains
* Connect heavy chains and light chains
* Connect light chains and light chains
DISULFIDE BOND
* Connect heavy chains and heavy chains
* Connect heavy chains and light chains
* Connect light chains and light chains
- Found in between CH1 and CH2
- Has high proline and hydrophobic residue
HINGE REGION
A.K.A. Flexible region
HINGE REGION
Amino acid in hinge region that causes flexibility
Amino acid: Proline (causes flexibility)
Regions or section in an Ig molecule
Domain
What are the domains in 1 Light chain?
1 Light chain
o 2 domains: VL (variable light) and CL (constant light)
What are the domains in 1 Heavy chain and specific to each Ig?
4 domains: 1 VH and 3 CH
In one monomer it contains _ domains except for
_________________ and _____________
In one immunoglobulin, it contains _ domains
In one monomer it contains 4 domains except for
pentameric (IgM) and dimeric form (IgA)
In one immunoglobulin, it contains 6 domains
- _________________- antigen binding site known also as the paratope
- _________________- CH2 and CH3, where B cells, T cells and
complement bind to
- Fab site- antigen binding site known also as the paratope
- Fc region- CH2 and CH3, where B cells, T cells and
complement bind to
2 enzymes
- PAPAIN DIGESTION
- PEPSIN DIGESTION
Cleaves the Ig above the hinge region
PAPAIN DIGESTION
It will give 3 fragments of a monomer and what are they?
PAPAIN DIGESTION
2 Fab + 1 Fc
Cleaves the Ig below the hinge region
PEPSIN DIGESTION
It has 2 fragments and what are they?
F(ab)2 + Fc
MONOMER
* Basic Ig structure
* IgG, IgD, IgE, IgA
(Which is the most?)
o Most of the immunoglobulins are a monomer
* 2 binding site (2 valence)
MONOMER
* Basic Ig structure
* IgG, IgD, IgE, IgA (most)
o Most of the immunoglobulins are a monomer
* 2 binding site (2 valence)
Prevents the enzymatic degeneration of enzyme among secretions
DIMER
In Dimer, It has a ________- additional structure, also known as _________
In Dimer, It has a J chain- additional structure, also known as joining chain
How many binding site and valence in monomer, dimer, and polymer?
Monomer- 2 binding site (2 valence)
Dimer- 4 valence- 4 binding sites
Polymer- 10 valence- 10 binding sites
Do polymer have J chain?
Yes, only monomer doesn’t
> 2 monomer
POLYMER
Ig that is polymer?
IgM- pentamer
