Antibodies Flashcards
Stage wherein secretion of the antibody happens
Plasma cells
What are the surface markers that remains on the cell surface throughout the subsequent developmental stages of the B cell?
CD 19, CD24, CD45R, CD25
What is used to determine the structure of immunoglobulins?
serum electrophoresis
What material is used for the serum electrophoresis?
Agarose gel with ph 8.6
Where do immunoglobulins appear during serum electrophoresis?
Gamma region
They are the ones involved in the secretion of antibodies
immunoglobulins
Functions of immunoglobulins
Opsonization, complement activation
Most abundant protein in serum electrophoresis
Albumin
Where is the albumin located during the serum electrophoretic activity?
Left side most corner
In conjunction with Alpha 1, we have…
Alpha 1 antitrypsin, alpha fetoprotein
In conjunction with alpha 2 globulin, we have…
Ceruloplasmin, haptoglobin, alpha 2 macroglobulin
In conjunction with the beta globulin, we have…
Transferrin, hemopexin, complement system, fibrinogen, lipoproteins
in what medical condition is beta-gamma bridging involved?
liver cirrhosis
Apart from liver cirrhosis, a spike pattern within the gamma region is associated with what?
multiple myeloma
most common protein seen in urine associated with multiple myeloma
bence jones proteins
at what temperature does bence jones proteins precipitate and dissolve?
precipitate at 60C and dissolve at 80C
non-covalent forces that hold together the h and l chains
disulfide bond
who worked with IgG to discover the structure of Ig?
gerald edelman, rodney porter
his work centered on the use of analytical ultracentrifuge to separate Ig on the basis of molecular weight
edelman
what is the sedimentation coefficient of intact IgG?
7s
what was used by edelman to obtain the 7s/unfold the molecule?
7M urea
reducing agent used to cleave the exposed sulfhydryl bond
2-Mercapthoethanol
sedimentation coefficient and molecular weight of H chain
3.5s, 50 000 D
sedimentation coefficient and molecular weight of L chain
2.2 S, 22 000D
his work was based on the use of the proteolytic enzyme papain
porter
where was the Ig subjected for the papain digestion?
carboxymethyl cellulose ion exchange chromatography
what fragment crystallized at 4C?
FC
it has no antigen binding capacity; also known to represent the carboxyl terminal halves of the 2 h chains
fragment crystallizable
fragment found to have antigen binding capacity
FAB region
where is the fab fragment located?
n-terminal or amino terminal
he used pepsin to obtain additional evidence for the structure of Ig
Alfred Nisonoff
where does proteolytic enzyme cleave the IgG?
carboxy-terminal
similar to FC but disintegrated into smaller pieces
FC’
it cleaves the antibody into 2 fragments (1 fab, 1 fc)
pepsin digestion
it cleaves the antibody into 3 equal fragments ( 2 fab, 1fc)
papain digestion
under the pepsin digestion, what is the composition of 1 fab?
2 light chains, 2 halves of h chain
region in light chain associated with the variable region
fab region
region in light chain associated with the constant region
fc region
Ig light chains that has 2 domains and 4 domain heavy chain
IgG, IgA, IgD
Ig that has 2 domains on the light chain and 5 domains on the heavy chain
IgE, IgM
Component of fab fragment and fc fragment in papain digestion
FAB- 1 L chain and 1/2 of H chain
FC- 2 halves of H chain
Component of 1F(ab)2 and 1Fc in pepsin digestion
1F(ab)2- 2L chain and 2 halves of H chain
Fc- 2 halves of H chain
What revealed that there were 2 main types of L chains?
Analysis of bence jones proteins
Type of l chain that accounts for 200 amino acids
Kappa
Type of l chain that accounts for 220 amino acids
Lambda
What chromosome is kappa l chain encoded?
Chromosome 2
What chromosome is lambda l chain encoded?
Chromosome 22
This chain detects the immunoglobulin class
H CHAIN
Constant region of the heavy chain
CH1, CH2, CH3
Unique amino acid sequence
Isotype
Minor variation
Allotype
Variation in the variable region
Idiotype
Segment of H chain located between the CH1 and CH2 regions
Hinge region
What is the hinge region mainly composed of?
Amino acid proline
Allows for flexibility and makes the antigen binding sites work independently
Proline
Ig with proline
IgG, IgA, IgD
Where is the basic immunologic structure of hinge region based on?
Valence
How many antigen binding sites does monomer have?
2
How many antigen binding sites does dimer have?
4
How many antigen binding sites does polymer have?
More than 4
Monomers
IgG, IgD, IgE, Serum IgA, IgM found on surface area of b cells
Dimer
Secretory IgA
Polymer/Pentamer
IgM
Most predominant Ig in humans
Has 4 subclasses
IgG
All types of IgG can cross the placental barrier except:
IgG2
All types of IgG can participate in complement fixation except:
IgG4
Most effective Ig for complement fixation?
IgM
Most efficient IgG in precipitation reaction:
IgG
Most efficient Ig in agglutination reaction:
IgM
Aka macroglobulin
19s sedimentation rate
970 000 D
IgM
General Half-life of IgM
10 days
Half-life of IgM in serum
6 days
Half-life of IgG
23 days
Where is the pentamer form of IgM found?
Secretions
Where is the monomer form of IgM found?
Surface of B cells
Serves as linkage to the points for the disulfide bonds between the two adjacent monomers
J chain
These Ig has J chain
secretory IgA and IgM
Considered as the most primitive Ig
IgM
Ig that is first to appear in a maturing infant
IgM
Primary response antibody
IgM
Functions of IgM
Complement fixation, agglutination, opsonization, toxin neutralization
Function of IgG
Cross the placental barrier, complement fixation, opsonization, neutralization of toxins and viruses, participate in agglutination and precipitation
Ig that exhibits a star like shape appearance
IgM
How many valence does the IgM have?
10
Can the IgM cross the placental barrier?
No
It has longer lag phase and no antibody production
Primary response
When exposed again to the same antigen it shows shorter lag period with an increased antibody production
Secondary response
The Ig that is primarily involved in the secondary response
IgG
Does the IgM have memory cells?
No
Ig taht is sensitized within the plasma cells and is found in the MALT
IgA
Serum IgA
Monomer
Has 13 more amino acids in the hinge region
IgA1
secretory IgA
Dimer
Found in MALT, milk, sweat, tears, saliva
IgA2
Found in IgA2 that prevents degradation which makes IgA2 more resistant to some bacterial proteinases
Secretory component
Who primarily produces the secretory component?
Epithelial cells
Ig that is found on the surface of immunocompetent but unstimulated B lymphocytes
IgD
Second type of Ig to appear during antigenic stimulation
IgD
Least abundant Ig in the serum
Only 0.0005%
Most heat-labile
Does not participate in typical Ig reactions
IgE
Where do IgE attach by means of specific surface proteins?
Basophil and mast cells
Specific surface proteins found exclusively on basophils and mast cells
high affinity FCRI receptors
What type of hypersensitivity does the IgE accommodate?
Type 1 hypersensitivity
What type of hypersensitivity does IgG and IgM accommodate?
Type 2 and type 3
Is IgE involved in complement fixation?
No
Immune mechanism of the hypersensitivity reaction of IgE
Release mediators from mast cells and basophils
Examples of type 1 hypersensitivity reactions
Anaphylaxis, hay fever, food allergies, asthma
Immune mechanism for type 2 hypersensitivity reaction of IgG and IgM
Cytolysis due to antibody and complement
Examples of type 2 hypersensitivity reaction
transfusion reaction, autoimmune hemolytic anemia, HDN
Immune mechanism of IgG and IgM for type 3 hypersensitivity reaction
Deposits antigen-antibody complexes
Examples of type 3 hypersensitivity reaction
Serum sickness, arthus reaction, lupus erythomatosus
Cells responsible for mediating type 4 hypersensitivity reaction
T cells
Immune mechanism of t cells for type 4 hypersensitivity reaction
Release of cytokines
Examples of type 4 hypersensitivity reaction
contact dermatitis, tuberculin test, pneumonitis
Medical condition that is in conjunction with the RH result of mother and fetus (different)
hemolytic disease of the newborn
Contradictory RH between the mother and the fetus can lead to what
spontaneous abortion, miscarriage, death
What Ig can trigger the classical pathway?
IgG and IgM
What Ig can trigger the alternative pathway?
IgA
Postulated that certain cells had specific surface receptors for antigen that were present before contact with antigen occurred
Lock and key concept
Erlich’s side-chain theory
individual lymphocytes are genetically preprogrammed to produce one type of Ig
Clonal selection theory
Who independently supported the clonal selection theory?
Niels jerne and macfarlane burnet
Antibody producing cells are capable of synthesizing a generalized type of antibody and when contact with antigen occurs the antigen serves as a mold or template
Template theory
Who proposed the template theory?
Felix haurowitz
Produce antibody arising from a single b cell
Monoclonal antibody
Who discovered the technique to produce antibody arising from a single b cell?
George kohler and cesar milstein
It revolutionized serological testing
Monoclonal antibody
What enzyme does myeloma cells lack?
HGPRT (hypoxanthine-guanine phosphoribosyltransferase)
Important enzyme to synthesize nucleotides from hypoxanthine and thymidin
HGPRT (hypoxanthine-guanine phosphoribosyltransferase)
Culture of hybrid cells that results from the fusion of B cells and myeloma cells
Hybridoma
Cells that are harvested from the mouse after being injected by antigen
Spleen cells
Cancerous plasma cells
Myeloma cells
Media supplemented with this brings about the fusion of plasma cells with myeloma cells producing a hybridoma
PEG (polyethylene glycol)
What selective culture media are the fusion cells placed?
HAT (media with hypoxanthine, aminopterin, thymidine)