Antibodies - Structure & Function Flashcards
1
Q
What is an antibody ?
A
- also called an immunoglobulin
- serum glycoprotein
2
Q
Where are antibodies made?
A
- made in activated B lymphocytes called plasma cells
3
Q
What do antibodies do?
A
- interacts with foreign molecules called antigens
- renders foreign bodies more susceptible to damage & elimination
4
Q
What are some structural features of antibodies ?
A
- heavy & light chains
- constant & variable regions
- antigen binding site
- hinge
- effector binding sites
5
Q
Describe Heavy & Light Chains
A
- 4 polypeptide chains
- they form 2 pairs with N termini aligned
6
Q
Define Epitope
A
epitope is the 3D surface on an antigen which interacts with the paratope on the antibody
7
Q
Define Paratope
A
the 3D surface on an antibody which interacts with with the Epitope on an antigen
8
Q
Define primary immune response
A
initial encounter with a new antigen
9
Q
What happens with prolonged or subsequent exposure to an antigen ?
A
- larger & faster secondary immune response
10
Q
What are some functions of antibodies ?
A
- neutralisation of toxins
- initiation of inflammation
- agglutination
- neonatal immunity
- opsonisation to enhance phagocytosis
11
Q
Describe IgG
A
- crosses placenta
- antitoxin
- activates complement
- activates macrophage & polymorphs to remove bacteria
12
Q
Describe IgD
A
- small antibody
- small amount in blood
- mostly present on mature B cell surface, where it may be involved in triggering cell division
13
Q
What are some examples of antibodies ?
A
IgG, IgA, IgM, IgD, IgE
14
Q
What are some direct diagnostic use of Ab?
A
- quantitation of antibody in blood enables identification of pathogen & monitoring progress of infection
- monitors body own immune response
15
Q
What are some uses of purified Ab ?
A
- passive immunisation
- antiRhD
- delivery of other agents
- cleaning up bone marrow in leukaemia
