Clonal Selection/ Antibody Structure Flashcards
Major Features of clonal selection (1):
The immune system is comprised of a ____________ population of billions of different ______________
heterogeneous
lymphocytes
Major Features of clonal selection (2):
Each individual lymphocyte is _____________ for a __________________ of an antigen
specific
single epitope
Major Features of clonal selection (3):
This _________-________ is by virtue of each lymphocyte’s unique __________________ _______________
antigen-specificity
surface receptor
Major Features of clonal selection (4):
Only a ________ number of lymphocytes will recognize a specific antigen
small
Major Features of clonal selection (5):
_____________ of an antigen signals the cell to undergo _____________
Recognition
PROLIFERATION
Proliferation
results in a clone of cells all expressing receptors with the same antigen-specificity
Major Features of clonal selection (6):
Proliferating lymphocytes will eventually differentiate into either _____________ cells or _____________ cells
EFFECTOR
MEMORY
Clonal selection holds true for both:
B & T cells
In the case of B cells—> the antigen -specific receptor is
membrane-bound immunoglobulin (Ig)
membrane-bound immunoglobulin (Ig) =
antibody (Ab)
Plasma cells
Effector B cells that are Ab-secreting cells
Memory B cells
long-lived cells with membrane-bound Ig
If any exposure to the antigen occurs subsequent to the initial exposure, what cells are more easily “triggered?”
memory cells
What are lymphocytes that have not yet encountered their specific antigen?
Naive lymphocytes
The immune system is able to respond in a _______ period of time upon subsequent infection. This is ___________ because the pathogen is not as ______________ ______________ when the body mounts the immune response.
shorter
advantageous
well established
What cells also produce an immune response larger in magnitude than naive lympocytes?
memory cells
What are antibodies (Ab) and where are they found?
Glycoproteins found in serum, ECF & mucosal secretions
What secretes antibodies?
Secreted by effector B cells (plasma cells) in response to antigens (Ag)
Antibodies are _______- specific. What does that mean?
antigen
They will bind to one particular antigen and not to others
Are antibodies globular or fibrous?
globular
What can be used to separate serum proteins?
electrophoresis
Serum proteins are separated into 4 major fractions:
albumin
alpha-globulin
beta-globulin
gamma-globulin
Basic structure of an antibody molecule ______ consists of ____ chains:
_____ ____ chains + _____ _____ chains
monomer
4
2 heavy (H) chains + 2 light (L) chains
In any one antibody molecule, the 2 ________ chains are identical to each other.
heavy (H)
The two L chains are identical to each other as well (T/F)
True
What is each H chain linked to an L chain by?
What kind of bond?
disulfide (S-S) bond between cysteine residues
covalent
Are the two H chains linked to each other by a S-S bond? (Y/N)
What is unique about this particular linkage?
yes
produces a flexible region
What is the flexible region of referred to as?
Hinge region
What enzyme cleaves Ig at the hinge regions?
papain
Proteolytic digestion with papain results in:
Fab & Fc fragments
Each monomer contains two identical ______ regions and one _____ region
Fab
Fc
Fab includes:
1 complete L chain & part of 1 H chain
What does Fab stand for?
Fragment antigen binding
How many binding sites does binding site for an antigen does each Fab contain?
one
How many Fabs are there per antibody molecule monomer?
two
Each monomer contains _____ binding sites for an antigen.
Are these binding sites identical to each other? (Y/N)
What is this property called?
two
Yes
Bivalency
What does the Fc region of the antibody molecule determine?
“biological activity”
The Fc region determines the specific ________ function(s) that the immune system will take on the __________-_________ complex?
effector
ANTIGEN-ANTIBODY COMPLEX
The Ig chain consists of tightly folded region of about ______ amino acids?
What are these regions called?
100
domains
Domains =
immunogolobulin folds
How many domains does a light chain have?
2 domains
How many domains does a heavy chain have?
4 (sometimes 5) domains
The domains at the _-________ in bothy heavy and light chains is extremely _________ in amino acid sequence amongst different antibodies.
N-terminus
variable
What are the variable regions (V regions)?
VH, VL
What are the constant regions (C regions)?
CH, CL
The _______ regions of an antibody molecule are where antigen-specificity of a particular antibody resides.
variable regions
Variable region of 1 light chain + variable region of 1 heavy chain = shape that?
What is this site called?
recognizes & binds antigen
Antigen binding site
What parts of antibodies actually make contact with antigen?
Complementarity- determining region (CDR)
CDRs only consist of light chains (T/F)
False
CDRs are stretches of AA’s within the variable regions of both heavy and light chains
Each binding site has ____ CDRs: ___ VH CDRs & ____VL CDRs
6 CDRs : 3 VH CDRs & 3 VL CDRs
How many classes of Ig are found in mammals?
5
What are the five classes of Ig based on?
the sequence of the HEAVY CHAIN CONSTANT REGION
What are the classes and their H- chain designation?
Which classes have 3 constant region domains (CH1-CH3) in their heavy chains?
Where is a hinge present?
IgG, IgA, IgD
between CH1 & CH2 domains
Which classes have 4 constant region domains (CH1-CH4) in their heavy chains?
Where is the hinge present?
IgM, Ig E
between CH2 & CH3 domains
All five Ig classes are found in the serum, but ____ IS BY FAR THE MOST DOMINANT SERUM Ig
IgG
IgM is present in the serum as a monomer. (T/F)
False
Which three classes are present as monomer in body fluids?
IgG
IgD
IgE
_____ is present as a monomer and dimer in serum
IgA
____ is present as a PENATMER in the serum
IgM
In mucus, ___ is present as a _______
IgA
dimer
What can form polymeric Ig?
Both IgM & IgA
What is found in the serum as a pentamer?
IgM
What is each pentamer is held together by?
One J chain polypeptide
J chain =
“joining chain”
Why is IgM confined primarily within the bloodstream?
IgM exists as a pentamer—> a large molecule
IT CANNOT PASS OUT OF THE CIRCULATION INTO BODY TISSUES- it is too big
How many antigen binding sites does IgM pentamer have?
10
each monomer has 2 antigen binding sites
IgA is found in the serum as monomers and dimers (T/F)
True
In mucosal secretions, IgA is ONLY found as ________.
dimers
Each dimer includes: one _ _____ _____________ & one additional polypeptide called __________ __________
J chain polypeptide
SECRETORY COMPONENT (SC)
What is the IgA in mucosal secretions called?
secretory IgA
Most species produce two types of Ig light chains: ___ & ___
An antibody molecule can have both kappa or lambda light chains. (T/F)
False;
it has either kappa or lambda light chains
Within any individual antibody molecule, the two light chains will be either:
both kappa or both lambda
What is multiple myeloma?
cancer of a plasma cell (an effector B cell)
A single B cell becomes __________.
What is it do to the bone marrow?
neoplastic
growing out of control and crowding out the bone marrow
What is the antibody the plasma cells will produce in reference to the myeloma?
myeloma protein
Is myeloma protein a normal antibody?
Is it the problem?
Yes
No, its that it is produced in very large amounts
Patients with multiple myeloma will have a very large ___-globulin peak in serum electrophoresis
gamma- globulin
