Question | Answer |
Where do B cells originate? | Bone Marrow |
By what method does Bcells make their BCR's? | gene re-arrangement |
What gene segments do the heavy chain consist o? | One V, One D, One J and One C |
What gene segments do the light chain consist of? | One V, one J and one C |
What is the specific antigen that the B cell binds to called? | Cognate antigen |
What part of the cognate antigen does the BCR bind to? | Epitope |
What are the BCR accessory molecules? | IgAlpha and IgBeta |
What can co-stimulation can occur to reduce the amount of cross linking by 100-fold? | Complement receptor and complement fragments on the antigen |
In the T-cell independent pathway, what secondary simulation interaction occurs? | TLR and LPS |
In the T cell dependent pathway, what secondary co-stimulation interaction occurs? | CD40L and CD40 |
How does class switching occur? | Gene re-arrangement in the constant region |
What is IgM good for? | Activating complement |
what shape is IgM? | Pentameric |
What is IgG good for? | Neutralising viruses , opsonisation, crossing the placenta and ADCC |
What is IgA good for? | Protecting the mucosal surfaces as it is resistant to degradation |
Why is IgA resistant to degradation? | Due to the J chain |
What shape is IgA? | Dimeric |
What is IgE good for? | Killing parasites |
How does IgE work? | Fc receptors on mast cellls bind to IgE. When Fab region of IgE binds to parasite, mast cell degranulates |
What two career choices do B cells have? | Plasma cells or memory cells |
What cells do MHC-I present to? | Cytotoxic T cells |
What cells do MHC-II present their antigen to? | Helper T cells |
What cells express MHC-I? | All nucleated cells |
What cells express MHC-II? | Antigen presenting cells |
What are the three MHC-I genes? | HLA-A, HLA-B, HLA-C |
Outline the three steps in MHC-I processing | 1. Degradation of proteins to peptides
2. transport of the peptides to ER via TAP proteins
3. Binding of peptide to MHC-I |
What genes are responsible for MHC-II? | HLA-DP, HLA-DQ, HLA-DR |
What covers the MHC-II binding site in the ER? | Invariant chain |
What is the invariant chain converted to in the endosome? | CLIP |
What removes CLIP to allow binding of peptide to MHC-II? | HLA-DM |
What is TLR-2 responsible for? | Peptidoglycan |
What is TLR-4 responsible for? | LPS |
What is TLR-5 responsible for? | Flagellum |
What i TLR-7 responsible for? | ssRNA |
What is TLR-3/9 responsible for? | dsDNA |
What are the three APC? | Dendritic cell, macrophage and B cell |
During the DC resting phase, the expression of which molecules are low? | B7 and MHC-II |
When the DC migrates to the lymphocytes, what does it recruit from the blood to replace them? | Monocyte |
Why do macrophages express MHC-II if they dont go to lymph nodes? | Re-stimulate the T helper cells |
What is the usefulness of B cells as APC? | It can generate lots of MHC-II quickly in response to a low conc. of antigen in subsequent infections |
What are the two types of TCR? | Alpha and beta, OR gamma and delta |
What accessory molecule does the TCR need to be activated? | CD3 |
What co-receptor does MHC-I bind with? | CD8 |
What co-receptor does MHC-II bind with? | CD4 |
What do Th1 cytokines fight against? | Bacterial infections |
What do Th2 cytokines fight against? | Parasites |
What cytokines stimulate Th cells to become Th1? | IL-12 |
What cytokines stimulate Th cells to become Th2? | IL-4 |
What substance does Tc cells secrete? | Perforin and granzyme |