lecture 2 Flashcards
Naive and active B/T cells circulate blood by leaving LN through what?
efferent vessel
how do naive B cells survive w/o Ag?
BCR make own survival signal when there is no Ag
what do naive B/T cells depend on to survive?
- signals from Ag receptors
2. cytokines
how do Naive T cells survive w/o Ag?
TCR recognize self Ag weekly, but not enough to start cloning
most important cytokine for T cell survival is what?
IL-7
what does IL-7 do for the survival of naive T cells?
promotes low level cycling
what cytokine is required for naive B cells survival?
BAFF (B cell activating factor)
what cell stage are naive cells in?
G0
what cell stage do stimulated cells enter?
G1
what cytokines are need for T cell development?
IL-1, 2, 6, 7
most mature naive T cells are where? and NOT doing what?
periphery & NOT proliferating
what 2 kinds of T cells develop when they undergo selection?
T helper cells & cytotoxic T cells
what cytokines are need for B cell development?
IL - 1, 6, 7
what Ig’s are expressed on B cells?
IgM & IgD
when activated, what do B ells mature into?
plasma & memory cells
why do B cells need helper T cells?
B cells present Ag to helper T, the B cells can proliferate & make antibodies
what do plasma cells make & secrete?
antibodies
what are antigen presenting cells function?
- capture, process, display Ag to lymphocytes in LN
2. provide signals to stimulate proliferation & differentiation of lymphocytes
Do B & T cells need APC for activation?
no, only T cells
what are 4 types of APCs?
- DC - major type for T
- macrophages - cell mediated
- B cells - humeral (present to helper T cells)
- follicular DC - B cells
what are DC very important for?
activation of Naive T cells
DC’s maturation is dependent on what cytokine?
Flt 3 ligand
Do DC’s secrete cytokines?
yes
classical DC characteristics?
in skin, mucosa, organ parenchyma. when activated, go to LN & present Ag to T cells
plasmacytoid DC characteristics
- early responders to viral infections
- recognize nucleic acids of intracellular viruses
- produce – IFN alpha/beta (type 1)
what does IFN alpha/beta have?
potent antiviral activities
follicular DC characteristics
- display Ag to B cells
2. keep complement - fixed Ag for a while, this provides antigenic stimulus that drives Ab affinity maturation
what type of cell has functions similar to effector T cells, but NO Tcells antigen receptors?
Innate Lymphoid cells (Natural Killer cells)
what are 3 functions of Innate Lymphoid Cells?
- provide early defense
- stressed/damaged cells & eliminate them
- help with adaptive response
what kind of cells is a natural killer cell?
innate lymphoid cell
what cytokine do NK cells secrete?
IFN- gamma
where in the thymus is the white/red pulp?
what is inside white pulp?
- medulla
2. T cells developing
what are the white pulp zones called in the spleen?
- T cell zone “ periateriolar lymphoid sheath”
2. B cell zone “ germinal center”
how do naive B/T cells enter the LN?
artery -> HEV -> go to zones
