3 Humoral Immunity Part 1 Flashcards
Alright I know some cards are long…
But I spent a lot of time integrating concepts scattered across different slides to make comparisons simple, so that is why.
T/F Only a few B cells are normally present in the periphery that can bind any 1 antigen?
True
T/F a mature B cell requires a costimulatory signal in addition to BCR engagement when it finds its antigen?
True
What molecules are expressed on B-1a cells?
IgM high
IgD lo
CD11b
CD5
What molecules are expressed on B-1b cells?
IgM high
IgD lo
CD11b
What molecules are expressed on B-2 MZ (marginal zone) cells? Where are these cells found?
IgM high
IgD lo
-Spleen white pulp marginal zones
What molecules are expressed on B-2 FO (follicular) cells? Where are these cells found?
IgM lo
IgD high
CD23
-All peripheral lymphoid organs, esp follicles of spleen and lymph node
Where are both types of B-1 cells typically found?
lung pleura and peritoneal cavity (just outside GALT & BALT) and tiny bit in spleen, lymph nodes
What kind of antigens do both types of B-1 cells recognize?
Macromolecules usually produced by microbes esp in cell walls:
- Polysaccharides
- Phospholipids
- Self-antigens like phospholipid/cell membrane proteins
What is the reason for why B-1 cells only recognize certain types of antigens?
B-1 cells contain only a restricted set of the V(heavy chain) gene segments
What types of B cell is known to be a constant source of “natural” IgM antibodies? Which are an immediate source of IgM’s (within hours) of specific IgM’s? What do these IgM’s do?
- B-1
- MZ B-2’s
- Pool of ready-to-use antibodies for early stages of infection
IgM’s are biased to attack what?
Microbial products like cell walls (like the B-1 cells that produced them!)
Where are B-2 cells produced? Where do they mature?
- In fetal liver and in bone marrow
- In spleen
Which B cell type is responsible for young childrens’ susceptibility to encapsulated bacteria? What do their antibodies target?
- MZ B-2 cells (these don’t appear until AFTER birth)
- Microbial products (like B-1 cells)
Which B cell types are abundant? Which are few?
Very abundant: FO B’2s
Low abundance: All B-1’s
Few: MZ B-2’s
T/F The B-1 progenitor and B-2 progenitor cell are the same?
False (Hematopoietic Stem Cell is their earliest common progenitor)
When in our lifetime are B’1s produced? How about FO B-2’s and MZ B-2’s?
- Mostly fetus/neonate, but persist and self-renew in adult. Also a few are still made from scratch in adult.
- FO B-2’s during fetus/neonate, then generated continuously throughout adulthood
- MZ B-2’s begin production AFTER birth
Of the 4 kinds of B cell, which produces highly diverse antibodies?
FO
Which B cell type is responsible for young childrens’ susceptibility to encapsulated bacteria? What do their antibodies target?
- MZ B-2 cells (these don’t appear for a while after birth)
- Microbial products (like B-1 cells)
Each mature B cell (in the periphery) expresses how many types of antibody?
1 (and only 1 antigen specificity)
What are the components of the BCR?
- Dif than T cells:
- Antibody (no signaling)
- CD79a, CD79b (a.k.a. Ig alpha/beta) are the signaling link
- Co-receptors CD 81, 19, 21 modify/amplify response
What happens to activated FO B cells?
Migrate toward border of the CD 4 T cell zones in lymph node
MZ B’s main function is?
Respond to blood-borne antigens (including those in the red pulp)
What is B cell signal 1? What happens w/ this signal alone?
- Engagement of multiple BCR’s
- Death/anergy
