ANTIBODIES Flashcards
are specific glycoproteins referred to as
immunoglobulins.
Antibodies
Where can antibodies be found
They can be found in blood plasma,
and in many body fluids such as tears, saliva, and
colostrum
primary function of an antibody in the
body defenses is to
combine with antigen, which can lead to bacterial or viral neutralization.
Immunoglobulins are produced by
They are Glycoprotein molecules which are
produced by plasma cells in response to
an immunogen and which function as
antibodies.
The Immunoglobulins derive
their name from the finding that
when
antibody-containing serum is place in an electrical field the antibodies, which were responsible for immunity, migrated with globular proteins.
Each antibody has how many binding site
2
Valence of an antibody:
Number
of antigen binding sites. Most
are bivalent.
Function of ig
1.Neutralize toxic substances
2.Facilitate phagocytosis and kill
microbes
3.Combine with antigens on cellular
surfaces and herby cause the
destruction of these cells wither
extravascularly of intravascularly
Antibody structure
Immunoglobulins are glycoproteins made up of:
- Four polypeptide chains (IgG):
a- Two light (L) polypeptide chains
b- Two heavy (H) polypeptide chains
- The four chains are linked by disulfide bonds
- Terminal portion of L-chain contains part of antigen binding site
- H-chains are distinct for each of the five Immunoglobulins
- Terminal portion of H-chain participate in antigen binding site
Part of antibody that forms fc fragment
Caboxyl terminal portion
Each heavy and lightchain has a
Constant and variable region
V-region lies in terminal portion of molecule
- V-region shows wide variation in amino a. sequences
- Responsible for the antigen binding.
- C-region lies in carboxyl or terminal portion of molecule
- C-region shows an unvarying amino acid sequence
- It is responsible for biologic functions
IgG
Structure
Percetage in serum antibodies
Locatoin
Half if
Complement fixation
Plcental transfer
Functions
Structure: Monomer
Percentage serum antibodies: 80%
Location: Blood, lymph, intestine
Half-life in serum: 23 days
Complement Fixation: Yes
Placental Transfer: Yes
Known Functions: Enhances phagocytosis, neutralizes
toxins and viruses, protects fetus and newborn.
Iga
Structure
Percetage in serum antibodies
Locatoin
Half if
Complement fixation
Plcental transfer
Functions
Structure: Dimer
Percentage serum antibodies: 10-15%
Location: Secretions (tears, saliva, intestine, milk),
blood and lymph.
Half-life in serum: 6 days
Complement Fixation: No
Placental Transfer: No
Known Functions: Localized protection of mucosal
surfaces. Provides immunity to infant digestive
tract.
Igm
Structure
Percetage in serum antibodies
Locatoin
Half if
Complement fixation
Plcental transfer
Functions
Structure: Pentamer
Percentage serum antibodies: 5-10%
Location: Blood, lymph, B cell surface (monomer)
Half-life in serum: 5 days
Complement Fixation: Yes
Placental Transfer: No
Known Functions: First antibodies produced during
an infection. Effective against microbes and
agglutinating antigens.
Igd
Structure
Percetage in serum antibodies
Locatoin
Half if
Complement fixation
Plcental transfer
Functions
Structure: Monomer
Percentage serum antibodies: 0.2%
Location: B-cell surface, blood, and lymph
Half-life in serum: 3 days
Complement Fixation: No
Placental Transfer: No
Known Functions: In serum function is unknown. On
B cell surface, initiate immune response.
Ige
Structure
Percetage in serum antibodies
Locatoin
Half if
Complement fixation
Plcental transfer
Functions
Structure: Monomer
Percentage serum antibodies: 0.002%
Location: Bound to mast cells and basophils
throughout body. Blood.
Half-life in serum: 2 days
Complement Fixation: No
Placental Transfer: No
Known Functions: Allergic reactions. Possibly lysis
of worms.
