Immunology Review Flashcards
What is CD2? What cells have it?
It’s LFA-3 - an adhesion molecule that’s part of the TCR and facilitates co-stimulation
On Th, Tc and NK cells
What cells have CD3 and what does it do?
Th and Tc cells - it’s part of the TCR and provides downstream signalling
What is CD16? What cells have it? What does it do?
It’s Fc-gamma-RIII
present on NK cells
it causes antibody dependent cell-mediated cytotoxicity
What is CD21 a receptor for? On what cells?
It’s the CR2 complement receptor for c3d - on B cells
What cells have CD28?
T cells (binds B7 for costimulation)
What is CD32 and what cells have it?
If’s the Fc-gamma-RII on B cells
What are the two forms of CD32 and what do they do?
a and b
a is first - it tells B cells to undergo phagocytosis
b is next - it tells the B cells to STOP phagocytosis and become a memory cell
What is CD35 a receptor for?
It’s the CR1 complement receptor for Cb3 on B cells
What cells have CD40?
B cells (Th cells have the CD40 ligand)
Why is the lymph node considered the most specialized secondary lymphoid organ?
it’s totally devoted to making an adaptive immune response
Where are the naive T cells located in the LN? Naive B cells?
T cells are in the cortex and the B cells are in the follicles
On average, how long are naive lymphocytes in the LNs if they don’t find antigen they like? How about if they DO find antigen
about 18 hours
days
If a B cell is activated with antigen and then receives help from a CD4+ cell, what are it’s two options?
It can differentiate to a plasma cell and exit into the circulation to immediately start pumping out IgG
or It can go back to the follicles and form a germinal center to make more B cells with that antigen specificity
What additional step happens to the B cells in the germinal centers?
somatic hypermutation (with the help of AID)
How does the spleen differ from lymph nodes and how does this determine what it’s used for?
Unlike the LNs, the spleen is only connected to circulation, not lymphatics
this means it’s specialized to filter antigen out of the blood instead of tissue
Children without spleens have a particuliarly hard time fighting off what kind of infection?
encapsulated bacterial infections in the blood
After leaving the thymus and bone marrow, how long does it take for mature lymphocytes to travel the body?
30 minutes
After those 30 minutes, what percentage of lymphocytes will be int he spleen, the lymph nodes, and the MALT?
45% in the spleen
45% in the lymph nodes
10% in the MALT
How do the lymph nodes leave circulation to enter lymph nodes?
through HEVs
What kind of cells do the naive T cells interact with in thelymph nodes? primarily…
fibroblast cells and dendritic cells
What kind of cell do the naive B cells interact with in the lymph nodes?
follicular dendritic cells
What are the stages of T cell and APC interactions?
stage 1: stochastic contacts - just tasting
stage 2: transient interactions (1-3 hours)
stage 3: T-cell clusters form (3-16 hours)
stage 4: T cell swarms (16-24 hours)
stage 5: T cell proliferation (over 24 hours)
How does antigen delivery to T cells differ from antigen delivery to B cells?
T cells need antigen presented on MHC, so they have to come from an APC
B cells can interact with soluble antigen via the BCR or complement-bound antigen via CD21 when there’s IgG already involved
What cell do the B cells “pass” the antigen onto in the latter situation from the previous card?
the follicular dendritic cells, which will then pass it on to a B cell that has antigen specificity for the antigen
