Flashcards in Lecture 46: Humoral Immune System Deck (13):
Describe the structure of a B-Cell Receptor
- 2 Heavy Chains
- 2 Light Chains
- Disulfide bridge between two heavy chains
- Antigen binding site at tips of 'Y'
- Variable + Constant regions
Different _____ for different B-Cells. Antigens don't need to be ______ / a peptide to be recognised.
- Processed (in a membrane)
B Cells (and T _____) are unique. Most B cells ( or _ Cells) express a different receptor. IgM and IgD are the predominant classes of ______ expressed on ___ B Cells. BCR IgM is present as a monomer, secreted IgM is a pentameter.
During a parasite infection, you'd want a lot of ___ around.
Constant regions on the antibody are able to be _____.
B Cells undergoing class switching maintaining their ____ _____.
- Antigen Specificity
Class / Isotype switching:
- IgM / IgD --> IgG --> IgA --> IgE
- Has to go in this direction
- Can't go backwards because you're looping out genes that have been tossed out and degraded
- Some steps can be skipped
- Selective expansion of unique B Cell Clones that interact with antigen
- Selective specificity
- Antigen specific B Cells then process and display (using MHC-II) to helper T Cells
- Helper T cells squirt out cytokines on to B Cells
B Cells that recognise _____ during an immune response are stimulated to undergo ___ ______.
- Cell Division
What is the difference between memory B Cells and Clone Plasma Cells?
- Antibody used as receptor on memory B Cells
- Stimulation of B cells by antigen + T cell and lymphatic tissue
- Express antibody as BCR, but do not secrete antibody
- Respond rapidly to antigen encounter and become plasma cells
Primary Immune Responses:
- Takes about 7-14 days before sufficient antibody is produced to eliminate pathogen
- Relatively low amount of antibody produced - mainly IgM (pentameric form)
- Very good at activating complement