Ch. 2 - Antibodies (RVSP) Flashcards
Protein electrophoresis fraction where Abs can be isolated
Gamma globulin fraction
Other name for antibodies (Abs)
Immunoglobulins
Primary function of Abs
To combine with Ag
5 classes of immunoglobulins
IgG IgM IgA IgE IgD
Ab produced early in an immune response
IgM
Major Ig in normal serum
IgG
Ig that crosses the placenta
IgG
Predominat Ig in secretions
IgA
Produces IgA
Plasma cells
Glycoprotein binded to by IgA after being transported through the intestinal epithelial cells or hepatocytes
Secretory component
Protects IgA from digestion by gastrointestinal proteolytic enzymes
Secretory component
Critical in protecting body surfaces against invading microorganisms because of its presence in seromucous secretions
Secretory IgA
Cell membrane Ig found on the surface of B lymphocytes
IgD
Ig found in the plasma of unparasitized individuals
IgE
Ig that mediates some types of hypersensitivity, allergies and anaphylaxis
IgE
Ig responsible for an individual’s immunity to invading parasites
IgE
Monomeric Igs
IgD
IgE
IgG
Monomeric and polymeric Ig
IgA
Pentameric Ig
IgM
Basic unit of an Ab molecule
Homology unit (domain)
Number of domains in a typical molecule
12
Ag-binding portion of the Ab; shows heterogeneity
Variable (V) region
Portion of Ab molecule; has a constant amino acid sequence
Constant (C) region
Loop structures in the variable regions that confer variability among different Abs or T cell receptors
Complementary-determining regions (CDRs)
Determines the class and subclass of an Ig molecule
H-chain type
2 L chain subtypes
Kappa (κ)
Lambda (λ)
3 globular regions of a typical IgG molecule
2 Fab regions
1 Fc portion
Links the 3 globular regions
Hinge region
Ag-binding fragments
Fab fragments
Third fragment after papain digestion of IgG; relatively homogenous; sometimes crystallizable
Fc portion
Enzyme used to digest IgG into 3 approximately equal fragments
Papain
2 Fab fragments that remain joined after pepsin digstion of IgG
F(ab)’2
Fragment that has a light chain and half of a heavy chain
Fd fragment
Point where the Fab regions can swing freely around the center of the molecule
Hinge
Residues present in the hinge region
Hydrophilic residues
Proline residues
Opens the hinge region making it accessible to proteolytic cleavage
Hydrophilic residues
Ig that is efficient in complement cascade activation and agglutination
IgM
Ig that has no interchain disulfide bonds between its heavy chains and an exposed hinge region
IgD
Ig that has an Fc region that binds strongly to a receptor on mast cells and basophils
IgE
The specific chemical determinant group or molecular configuration against which the immune response is directed
Antigenic determinant
3 principal categories of antigenic determinants
Isotype
Allotype
Idiotype
Dominant type of antigenic determinant found on Igs of all animals of a species
Isotype determinant
Antigenic determinant found in some, but not all, animals of a species
Allotype determinants
Produced by injecting the Igs of one animal into another member of the same species
Alloantibodies
Genetically determined variations representing the presence of allelic genes at a single locus within a species
Allotype determinants
5 sets of allotypic markers in humans that have been found
Gm Km Mm Am Hv
Antigenic determinant; a result of the unique structures on light and heavy chains
Idiotype determinants
Antigenic determinant; individual determinants characteristic of each antibody
Idiotype determinants
Location of the idiotypic determinants
Variable part of the Ab
2 forms of an immune reaction
- cell-mediated immunity (T cells and macrophages)
- production of Abs (B lymphocytes and plasma cells)
2 routes of entry of foreign substance that illicits a stronger stimuli
Intravenous
Intraperitoneal
Predominant type of Ig in primary antibody response
IgM
4 phases of the IgM antibody response after a foreign antibody challenge
Lag phase
Log phase
Plateau phase
Decline phase
Phase when no Ab is detectable
Lag phase
Phase when the Ab titer increases logarithmically
Log phase
Phase when the Ab titer stabilizes
Plateau phase
Phase when the Ab is catabolized
Decline phase
3 points of difference between an anamnestic response with a primary response
Time
Type of Ab
Ab titer
Difference in TIME between anamnestic response and primary Ab response
Shorter lag phase
Longer plateau
More gradual decline
Type of Ab predominantly found in anamnestic response
IgG
Ab titer in anamnestic response compared to primary Ab response
Higher Ab titer
Application of primary and secondary responses
Vaccination
Provides artificially acquired active immunity to a specific disease
Vaccine
Vaccine that allows for an anamnestic response, with an increase in Ab titer and clones of memory cells
Booster vaccine
Principal function of Ab
To bind Ag
2 significant secondary effector functions of Abs
Complement fixation
Placental transfer
2 molecules with important effector mechanisms in the activation of complement
IgG1
IgG3
Ability if a particular Ab to combine with a particular Ag
Specificity
Portion of the Fab molecule that has specificity; a cleft formed largely by the hypervariable regions of heavy and light chains
Combining site
Initial force of attraction between a single Fab site on an Ab molecule and a single epitope or determinant site on the corresponding Ag
Affinity
Functional combining strength of an Ab with its Ag
Avidity
Noncovalent combination of Ag with it respective specific Ab
Immune complex
Type of immune complex under conditions of Ag or Ab excess
Soluble complexes
Type of immune complex under conditions of equivalent amounts of Ag and Ab
Precipitate
3 factors that affect the level of circulating immune complexes
Rate of formation
Nature of the complex formed
Rate of clearance
Type of bond between Ag and Ab
Noncovalent
4 types of noncovalent bonds in Ag-Ab reactions
Hydrophobic bonds
Hydrogen bonds
Van der Waals Forces
Electrostatic forces
Major type of noncovalent bond between Ags and Abs
Hydrophobic bond
3 major hydrogen bonds in Ag-Ab interactions
O-H-O
N-H-N
O-H-N
Type of noncovalent bond; nonspecific attractive forces generated by the interaction between electron clouds and hydrophobic bonds
Van der Waals Forces
Type of noncovalent bond; results from minor asymmetry in the charge of an atom caused by the position of its electrons
Van der Waals Forces
Type of noncovalent bond; results from the attraction of oppositely charged amino acids located on the side chains of 2 amino acid residues
Electrostatic Forces
Refers to the event when the shapes of the antigenic determinants and the Ag-binding site conform to each other
Goodness of Fit
Complementary matching of determinants and binding sites
Goodness of Fit
Process where particulate Ags aggregate to form larger complexes in the presence of a specific Ab
Agglutination
Combination of soluble Ag with soluble Ab to produce insoluble complexes that are visible
Precipitation reactions
Reaction of Ag and Ab with a cellular indicator
Hemolysis testing
Measures immune complexes formed in an in vitro system
Enzyme-linked immunosorbent assay (ELISA)
4 tests for detection of Ag-Ab reactions
Agglutination
Precipitation reactions
Hemolysis testing
ELISA
Charge of Igs
Positively charged
Difference in electrostatic potential between the net charge at the cell membrane and the charge at the surface of the shear
Zeta potential
Process where the zeta potential is reduced
Sensitization (coating of particles)
Ig sometimes referred to as COMPLETE ANTIBODIES
IgM-type antibodies
Abs more efficient in exhibiting in vitro agglutination when the Ag-bearing erythrocytes are suspended in physiologic saline
Complete antibodies (IgM-type antibodies)
Abs that do not exhibit visible agglutination of salin-suspended erythrocytes, even when bound to the cell’s surface membrane
Nonagglutinating antibodies (incomplete antibodies) (IgG and IgA)
Purified Abs cloned from a single cell
Monoclonal Abs
Abs that exhibit exceptional purity and specificity and are able to recognize and bind to a specific Ag
Monoclonal Abs
Scientists that discovered hybridoma technique
Köhler
Milstein
Jerne
Cells used in the hybridoma technique
Cultured myeloma cells
Plasma cells from malignant tumor strains
Cultured myeloma cells
Virus used to induce the cells to fuse
Sendai virus
An influenza virus that causes cell fusion
Sendai virus
The Igs derived from a single clone of cells
Monoclonal Abs (MAbs)
Promotes cell membrane fusion in modern methods for producing MAbs
Polyethylene glycol (PEG)
7 uses for monoclnal antibodies
- analysis of cell membrane antigens
- indentifying and quantifying hormones
- typing tissue and blood
- identifying infectious agents
- indentifying clusters of differentiation for the classification of leukemias and lymphomas and follow-up therapy
- identifying tumor Ags and autoantibodies
- delivering immunotherapy