Stuff I Don't Know Flashcards
(41 cards)
Most B cells that come from the fetal liver are derived into what lineage?
B1
Most B cells that come from the bone marrow are derived into what lineage?
B2
Why do B1 cells exhibit a limited amount of diversity?
Because TdT is not expressed in the fetal liver
What does TdT do?
TdT adds or removed nucleotides to the exposed ends of the V, D, and J genes before they are reuinted. Further increasing genetic diversity of the antibodies.
Where is junctional diversity generated?
At the points between joining genes
Junctional diversity results from what?
The loss of nucleotides at the ends of genes via exonucleases and the addition of P and N nucleotides.
What are P nucleotides named for?
The palindromic appearance
Where are large numbers of B1 cells found?
Self-renewing populations are found in the peritoneum and mucosal sites.
What do B1 cells secrete?
They spontaneously secreted IgM antibodies that interact with polysaccharides, lipids, and oxidized lipids
What is another name for B1 cells?
Natural antibodies, because they are present in individuals without overt immunity
What do B1 cells mostly contribute?
IgM abs during early phases of infection
Where do B2 cells develop?
From SC’s in the bone marrow
Following rearrangement of their BCR chains, where do immature B2 cells relocate?
To the spleen
What do immature B2 cells differentiate into?
Marginal Zone (MZ) and Mature Follicular (FO) cells
Where are mature FO cells found?
They are recirculating lymphocytes
Where are mature MZ B2 cells found?
In the spleen (splenic marginal zone), some in LNs
FO B2 cells respond to antigens in what manner?
In a T cell dependent manner
In order for a FO B2 cell to turn into a plasma cell, what needs to happen?
T cell dependent activation
Are most MZ B cell responses dependent or independent of T cell activation?
Independent
Where are MZ B cells predominantly located?
In the marginal sinus of the spleen
Which immunoglobulin mediates the release of mediators from mast cells and basophils in response to an allergen?
IgE
Which of the following cell types do NOT express MHC class I molecules?
RBC’s
Where does loading occur in MHC class I?
The rough ER
Where does loading occur in MHC class II?
acidified endosome
