Antibody Flashcards
Substances, spec. glycoproteins, produced by B lymphocytes/plasma cells in response to antigenic stimulation
ANTIBODIES/IMMUNOGLOBULINS
Immune response in which antibody production occurs
HUMORAL
Same with antibody classes
Lies in the heavy chain
Pertain to IgM, IgA, IgG, IgE, IgD
ISOTYPE
Genetically determined differences, spec. in the amino acid sequence in the constant region
ALLOTYPE
VARIABLE REGION of the antibody
IDIOTYPE
STRUCTURE OF IMMUNOGLOBULINS:
1. Four (4) polypeptide chains:
2 IDENTICAL LIGHT CHAINS & 2 IDENTICAL HEAVY CHAINS
STRUCTURE OF IMMUNOGLOBULINS:
2. Both light & heavy chains held together by
COVALENT DISULFIDE BONDS
STRUCTURE OF IMMUNOGLOBULINS:
3. Heavy chains interconnected by
DISULFIDE LINKAGES
STRUCTURE OF IMMUNOGLOBULINS:
4. 2 Terminal Regions:
CARBOXYTERMINAL
AMINOTERMINAL
CONSTANT REGION
Constant amino acid sequence
Fc (crystallizable fragment / fragment crystallin) is present
CARBOXYTERMINAL
VARIABLE REGION
Varying antibody specificity
Determines the idiotype
Hypervariable portion of the variable region specifically binds with the epitope
AMINOTERMINAL
STRUCTURE OF IMMUNOGLOBULINS:
5. Treatment with PAPAIN will produce 3 fragments:
ONE Fc FRAGMENT
TWO Fab FRAGMENTS
Fragment crystalline
Involve in the Ig biologic function
ONE Fc FRAGMENT
Ig Biologic Function:
COMPLEMENT FIXATION
PLACENTAL TRANSFER OF Ig
BINDING SITE FOR CELLS
Antigen binding even without the Fc but cannot agglutinate or precipitate (MONOVALENT)
TWO Fab FRAGMENTS
STRUCTURE OF IMMUNOGLOBULINS:
6. Treatment with PEPSIN results in:
DIGESTION OF Fc FRAGMENT –> 2 Fab FRAGMENTS - 2 Ag COMBINING SITES (BIVALENT) –> Ag BINDING, PRECIPITATION, AND AGGLUTINATION
alpha, gamma, mu, epsilon, delta
HEAVY CHAIN
Site for the gene for heavy chain synthesis
CHROMOSOME 14
Either kappa or lambda
Found in two different loci
LIGHT CHAIN
Site for kappa light chain
CHROMOSOME 2
Site for lambda light chain
CHROMOSOME 22
Glycoprotein
Linking / bridging monomers together
Found in antibodies which consist of 2/more monomers
J CHAIN / JOINING CHAIN
___ - pentamer
___ - dimer
IgM
SECRETORY IgA
DOMAINS OF IMMUNOGLOBULIN:
VCH23CLH
VARIABLE REGION
CH2 (CONSTANT HEAVY CHAIN 2)
CH3 (CONSTANT HEAVY CHAIN 3)
CL (CONSTANT LIGHT CHAIN)
HINGE REGION
Specificity
Antigen binding site
Consists of Fab region
VARIABLE REGION
Binds with complement
Involved in the classical pathway
CH2 (CONSTANT HEAVY CHAIN 2)
Recognition site for antibody
Initiates classical pathway when bind
C1q
Antibodies involved in classical pathway
IgM & IgG
Cytotropic reactions involving WBCs
Links to the receptor on cell membrane
CH3 (CONSTANT HEAVY CHAIN 3)
WBCs:
MMMCB
MACROPHAGES
MONOCYTES
MAST CELLS
CYTOTOXIC KILLER CELLS
B CELLS
Responsible for light chain type
Either ___ but ___
CL (CONSTANT LIGHT CHAIN)
KAPPA OR LAMBDA
NEVER BOTH
KAPPA = ___%
LAMBDA = ___%
65
35
Between CH1 & CH2
Flexible region
Flexibility of the antibody can squeeze through or penetrate membranes and other structures
Flexibility is attributed to the amino acid that is abundantly present in it
HINGE REGION
Amino acid responsible for its flexibility
PROLINE
Classes of Immunoglobulins:
GAMED
IgG
IgA
IgM
IgE
IgD
Predominant Ig in humans bc ___
IgG
LONGEST RETENTION TIME / LONGEST CIRCULATION LIFE
Provides immunity to the newborn bc ___ bc ___
IgG
CAN CROSS THE PLACENTA
SMALLEST
Antibodies that can cross the placenta
IgG1 & IgG3
When IgG crosses placenta, the maternal Ab provides immunity to newborn
ACQUIRED NATURAL PASSIVE IMMUNITY
Mother and baby different blood types
Sensitize fetal RBCs → ___ → ___
INCOMPATIBLE PREGNANCY
LYSIS
HDFN (HEMOLYTIC DISEASE OF THE FETUS AND NEWBORN)
Fixation of complement
Most to least potent
IgG
IgG3 > IgG1 > IgG2
IgG - Opsonization aka ___
FACILITATED PHAGOCYTOSIS
Molecule that enhances phagocytosis by facilitating the linking or cross-bridging of the phagocytes and the target Ag
OPSONIN
Toxin and virus neutralization
Participates in agglutination and precipitation reaction
IgG
Best precipitating Ab
Monomer
Has no J chain
Predominant Ab in secondary / anamnestic response
IgG
4 Subclasses of IgG:
% of total IgG - number of disulfide bonds
IgG1 - 60% - 2
IgG2 - 23% - 4
IgG3 - 7% - 15
IgG4 - 4% - 2
Predominant Ab in primary immune response
IgM
IgM - first to appear in ___ and the last to leave in ___
PHYLOGENY
SENESCENCE
First to appear after a primary antigenic stimulus
IgM
Pentameric structure
IgM
Functions of IgM:
CAOT
COMPLEMENT FIXATION
AGGLUTINATION
OPSONIZATION
TOXIN NEUTRALIZATION
Most potent
Best in fixing complement bc ___
IgM
BIGGEST
Best agglutinating antibody
IgM
IgA exist as ___ in plasma and ___ in secretion
MONOMER
DIMER
Responsible for mucosal immunity
IgA
Only antibody with ___ - responsible for maintaining the structure of the antibody by preventing the enzymatic degradation of the structure
SECRETORY COMPONENT
2 Subclasses of IgA:
IgA1 & IgA2
Function is still unknown but believes to play a role in IMMUNOREGULATION
IgD
Control of antibody secretion and release in the circulation
IMMUNOREGULATION
Found on the surface of B-lymphocytes
IgD
Postulated to be an anti-idiotypic antibody
IgD
Monomer
IgD
Least abundant Ig in the serum
IgE
Heat-labile antibody
IgE
Binds strongly to mast cell and basophil receptor
IgE
Site of histamine production
MAST CELL
Mediates some types of hypersensitivity reactions
IgE
Other name of IgG
SERUM Ig
Other name of IgA
SECRETORY Ig
Other name of IgM
PENTAMERIC Ig
Other name of IgE
REAGINIC Ig