[DISCUSSION] MODULE 1 UNIT 3 Flashcards
•Glycoproteins (gamma globulins) present in serum/ plasma
ANTIBODIES
•Produced by plasma cells in response to exposure to antigen
ANTIBODIES
•React specifically with that antigen in vivo or in vitro
ANTIBODIES
•Part of adaptive immunity or humoral immune response
ANTIBODIES
•As glycoprotein: consist of:
polypeptide
carbohydrate
82 – 96%
4 – 18%
•Antigen receptors on the surface of B cells
Immunoglobulins
•Ability of the host to produce this is genetically endowed
Immunoglobulins
• The property of Immunoglobulins in vivo is determined by genes
specific recognition
• The expression of immunoglobulins on a B cell surface require the presence of
transmembrane sequence
• Permits insertion and anchorage of the immunoglobulins into the cell membrane
transmembrane sequence
•In the absence of this transmembrane sequence as occurs in plasma cells, the antibodies become
secreted into the plasma
TWO (2) HALLMARK PROPERTIES OF ANTIBODY
- SPECIFICITY
- DIVERSITY AND HETEROGENEITY
• Able to recognize and bind its particular antigen
- SPECIFICITY
• Complementariness of the antigenic epitope and antibody-combining site
- SPECIFICITY
• is based on a physical and chemical
reaction
- SPECIFICITY
• Able to recognize and respond to a vast array of antigen challenge in nature
- DIVERSITY AND HETEROGENEITY
• Extensive gene rearrangements
- DIVERSITY AND HETEROGENEITY
DISTRIBUTION OF ANTIBODIES
•Blood plasma / serum (in vitro)
•Saliva
•Tears
•Mucous secretions
•Milk colostrums
•Other body fluids
BIOLOGIC ACTIVITIES
- Primary:
- Secondary:
- Primary:
bind antigens specifically - Secondary:
a. Opsonization
b. Neutralization of toxins and virus
c. Complement fixation
d. Antibody-dependent cell-mediated cytotoxicity (ADCC)
STRUCTURE OF ANTIBODIES
•BASIC UNIT
•DISULFIDE BONDS
•REGIONS
•DOMAINS
• FRAGMENTS
•HINGE REGION
• S -VALUE
STRUCTURE OF ANTIBODIES
1950s by (?) - (USA)
1960s by (?) - (England)
Gerald Edelman
Rodney Porter
The Immunoglobulin Domain
•localized between the CH2 domains of the two H chains
CARBOHYDRATES
•Functions of the carbohydrate include:
- increasing the solubility of immunoglobulin
- providing protection against degradation
- enhancing functional activity of the FC domains
Ag binding
Fab
Valence= 1
Fab
Specificity determined by VH and VL
Fab
Effector functions
Fc
F(ab’)2
Pentamer
IgM
Monomer
IgG
IgE
IgD
Dimer
Secretory IgA
Monomer (7s)
IgG
IgG subclasses
IgG1
IgG2
IgG3
IgG4
Pentamer (19s)
IgM
Extra domain (CH4)
IgM
J chain
IgM
Third highest serum immunoglobulin
IgM
First immunoglobulins made by fetus and b cells
IgM
Fixes complement
IgM
Agglutination immunoglobulin
IgM
Binds to fc receptors
IgM
B cell surface immunoglobulin
IgM
Serum - monomer
IgA
Secretions (sIgA)
Dimer (11s)
J chain
Secretory component
Monomer
Tail piece
IgD
Monomer
Extra domain (CH4)
IgE
Action of IgE on Mast cells
*PROPERTIES OF THE DIFFERENT IMMUNOGLOBULIN CLASSES
•Tabulate as many properties as you can
•Differences among IgG subclasses and IgA subclasses
CLASSIFICATION OF ANTIBODIES
A. According to HOST
B. According to Production in the Immune response
C. According to Serologic Behavior
D. According to Temperature of Reaction
E. According to Complement Fixation
F. According to Monoclonal production
A. According to HOST
- Autoantibody
- Homologous / alloantibody
- Isoantibody/ isoagglutinins
- Heterophil(e) antibodies
B. According to Production in the Immune response
- Naturally-occurring
- Immune
C. According to Serologic Behavior
- Agglutinin
- Precipitins
- Blocking antibody
- Complete antibody
D. According to Temperature of Reaction
- Cold-reactive antibody
- Warm agglutinin/ warm-reactive antibody
E. According to Complement Fixation
- Complement-fixing
- Non-complement fixing
F. According to Monoclonal production
- Monoclonal antibody
- Polyclonal antibody
VARIABILITY OF ANTIBODIES
A. ISOTYPES
B. ALLOTYPES
C. IDIOTYPES
• Refer to the different classes of immunoglobulins
A. ISOTYPES
• Based on the heavy chain (g, m, a, d, e)
A. ISOTYPES
• Refer to genetic markers on the heavy chain of the Ig present on some individuals but not in others
B. ALLOTYPES
• Follows a simple Mendelian heredity
B. ALLOTYPES
• Refer to the unique specificity of the antibody conferred at the paratope on the basis of a.a. on the variable sequence of the Ig
C. IDIOTYPES
• All antibody molecules share the same (?) but display remarkable variability in the (?)
basic structural characteristics
regions that bind antigens
• An antibody molecule has a symmetric core structure composed of
two identical light chains and two identical heavy chains
• Antibody heavy chains and light chains both consist of (?) that participate in antigen recognition and (?)
amino-terminal variable (V) regions
carboxy-terminal constant (C) regions
help mediate some of the protective or effector functions of antibodies
C regions of the heavy chains
• The antigen-binding portion of an antibody molecule is the
Fab region
the C-terminal end that is involved in effector functions is the
Fc region