Immunology (Comp) Flashcards
(74 cards)
Changes from immature DC to mature DC?
Immature: highly phagocytic; low CCR7 expression; low B7 expression
Mature: less phagocytic; high CCR7 expression; high B7 expression
What guides DCs to the LN?
CCR7 chemokine
What is the function of B7.1 and B7.2 on DCs?
Co-stimulatory/gives signal 2 to T cell
Location of T cell maturation/pos neg selection?
Thymus
Location of T cell clonal expansion?
LNs and spleen
Timeframe to reach peak lymphocyte expansion?
7-10 days
What happens during signals 1-2 molecularly?
1: TCR binding MHC+peptide on DC
2: CD28 on T cell binds B7 molecules on DC
Signal 1 without signal 2 leads to _____
Tolerance
MHC/T cell for extracellular pathogens?
MHC II; CD4 T cell
MHC/T cell for intracellular pathogens?
MHC I; CD8 T cell
CTLA-4 function?
Negative regulator of T cells; stops clonal expansion (more division = more CTLA-4 expression)
How do superantigens cause a massive inflammatory response?
Bypass MHC restriction to bind both MHC/TCR outside of the peptide binding groove so can activate lots of T cells
Why is MHC polymorphism important on a pop health level?
One disease won’t be able to come and wipe out the entire population in one swoop
What 2 signals are needed to activate a naive B cell?
- BCR-antigen binding
- CD40/CD40L binding (Permission to activate from Tfh)
Do B cells always need T cell help to activate?
No–certain TLRs like LPS can activate them OR so many BCRs can be activated at once that it just activates
Chemokine that B cells use to find the B cell follicle?
CXCR5
Chemokine expressed by CD4 Tfh after DC contact?
CXCR5
What do follicular DCs do?
No digestion of antigen; keeps antigen on LN surface so B cells can see them
What is the chemokine to locate B cell follicles?
CXCR5
Where do plasma cells live?
Bone marrow, medullary chords (LNs), red pulp (spleen), or tissue
What happens in the dark zone of a germinal center?
Lots of proliferation; somatic hypermutation of the BCR
What happens in the light zone of a germinal center?
Antigen driven selection of B cell clones; class switching of BCR
Monoclonal vs polyclonal antibodies?
Monoclonal – exact same protein sequence from a single B cell clone
Polyclonal – antibodies from multiple B cell clones
Function of memory B cells?
Long-lived memory; if reactivated will go through same process as naive B cell, now it just has higher affinity already. Expresses but does NOT secrete antibody