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34 Cards in this Set
- Front
- Back
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plasmacytoid dendritic cells
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the first responders to viral infections which release tons of interferon
they must have TLRs or something.... |
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what kind of receptor do pro b cells have
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no receptor!!!
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what kind of receptor do pre b cells have?
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they have rearranged their heavy chain and it is coupled with a surrogate light chain
this is a pre-BCR |
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what kind of receptor do immature b cells have?
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an mIgM receptor with a rearranged heavy and light chain. no IgD yet.
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what kind of receptor do mature b cells have?
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mIgM and mIgD
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what kind of light chain do immature B cells have?
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kappas or lambdas
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what is a pre-T cell receptor?
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a rearranged beta chain and a surrogate alpha chain (created in double negative cells)
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what kind of receptor do DN T cells have
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no receptor or a pre TCR (beta and surrogate alpha)
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what kind of receptor do DP T cells have
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a pre TCR or an alpha beta T cell receptor
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what kind of rearrangement occurs in DN and DP t cells
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DN - beta, they then express a pre TCR
DP - alpha, they then express an alpha beta TCR |
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when / where do DP t cells become SP?
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after they have an alpha beta t cell receptor, depending on which MHC it recognizes they down regulate either CD8 or CD4.
this occurs in the medulla |
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AIRE
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auto immune regulator gene
causes the medullary epithelial cells in the thymus to express peripheral antigens to aid in negative selection of T cells |
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where does positive selection occur in the thymus?
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after beta and alpha chain arrangement. this is in the cortex I guess
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where does negative selection occur in the thymus?
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after the alpha chain rearrangement? this occurs as the cell makes its way from cortex to medulla
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where are B cell and T cell areas within a lymph node?
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B cell - cortex
T cell - paracortex |
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what cell adhesion molecule interaction allows for leukocytes to transcytose from the post capillary venule into the lymph node?
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L selectin (on the L) and CD34 on the PCV
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shutdown phase
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after exposure to an antigen, the T cells specific to that antigen disappear from the blood because they are in the lymph nodes trapped by antigen presenting cells
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opsi
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overwhelming post splenectomy infection - this occurs in splenectomy patients because they cant filter bacteria (esp. gram pos) from the blood with their spleen
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what is largely responsible for the early T independent IgM response to bacteria?
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the spleen
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where are the T and B cell zones in the spleen?
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the T cells are located in the PALS - periarteriolar lymphoid sheath
the follicular B cells are outside of that the Marginal Zone B cells (T independent response) are outside of that |
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what is the T independent response
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marginal zone b cells dont need T cell activation to mount an early response to bacteria. they get stimulated move out into the red pulp and start pumping out IgM to control blood borne infection
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where do B cells and T cells interact in the spleen
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at the B - T cell border of course. after that the b cells move into b cell zone to form a follice / gc
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what is affinity maturation
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as B cells undergo clonal expansion in a GC, their receptor mutates. B cells with a higher affinity receptor receive a stronger signal and proliferate more. This is a darwinian type selection process for the highest affinity receptor in the germinal center. as the infection is cleared, the antigen concentration decreases and only the highest affinity receptor B cells keep receiving signal and survive. these are the ones that become memory B cells
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where does isotype switching occur?
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in the germinal center as clonal expansion occurs
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what enzyme aids in somatic hypermutation AND isotype switching?
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AID - activation induced cytidine deaminase
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what does an aid mutation cause?
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hyper-IgM syndrome
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where do future longlived plasma cells go to from the germinal center?
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the bone marrow
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what are T independent antigens
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some kind of polysaccharide on bacteria or repetiitve protein on viruses that can produce a strong enough B cell response without T cell help
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in the skin and mucosa there are special T cells that produce ____ to keep inflammation in check
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anti-inflammatory cytokines
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where do t independent plasma cells make all their IgM?
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in the red pulp
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leukemia cells have only a heavy chain with a surrogate light. what kind of leukemia
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pre-B cell leukemia
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chronic lymphocytic leukemia is a cancer of ____
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memory B cell
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multiple myeloma is from a cancer of _____
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plasma cells
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in affinity maturation, where do B cells encounter these antigens that they compete for?
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they are presented by follicular dendritic cells
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