Humoral Immunity Flashcards
Which cells mediate humoral immunity?
B cells which produce antigen specific antibodies
What is an epitope?
The specific part of an antigen that is recognised by the immune system
What kind of molecule is the B cell receptor?
A membrane bound antibody
What two cell types are produced after B cell activation?
- Plasma cells (effector cells)
- Memory B cells
What is the main difference between primary and secondary immune response?
Primary is slower, dominated by IgM and has lower antibody titres
Secondary is faster, IgG dominated and has higher and longer lasting titres
What is clonal expansion?
Rapid division of antigen specific lymphocytes into identical daughter cells after activation
What are the four main ways antibodies inactivate antigens?
- Neutralisation
- Agglutination
- Opsonisation
- Complement activation
What is the main function of the Fab region of an antibody?
Binds to the antigen and is epitope specific
What does the Fc region of an antibody do?
Binds to Fc receptors on immune cells mediation immune responses
Which antibody is first produced during an immune response?
IgM
Which antibody dominates the secondary immune response and is found in colostrum?
IgG
Which antibody protects mucosal surfaces?
IgA
Which antibody is involved in allergic responses and defence against parasites
IgE
Which antibody type is restricted mostly to the bloodstream?
IgM
Which antibody can readily move into extravascular spaces?
IgG
what is the role of IgE in helminth defense?
- Binds helminths
- Interacts with eosinophils via Fc receptors
- Triggers lysis
What happens when IgE sensitised mast cells encounter their specific allergen again?
They degranulate and release histamine causing allergic reactions
How do T cells help B cells?
B cells present antigen to helper T cells via MHC II which then provide activation signals
What is the difference in receptor generation between innate and adaptive immunity?
- Innate - germ line encoded
- Adaptive - receptors generated by gene rearrangement
