Lecture 16 complete Flashcards
(39 cards)
What response is initiated by the B cell recognizing an antigen?
The hummoral response
What makes an ab response depenedent on a T cell?
If it is a protein, called a T depdent ag
What facilitates the formation of germinal centers?
Follicular helper T cells
What occur in gernminal centers?
T dependent hummoral responses
Where do plasma cells that have been matured in the GC often go?
They go to the bone marrow where they may stay for many years.
These long lived Ab contintualsly secrete Ab providing immediate protection
What type of Ab response does not require T helper lymphocytes?
A multivalent non protein Ag with repeating epitopes such as a polysaccharide, some lipids, and nucleic acids
If a B cells is activated by a protein, what might it differentiate into?
A memory cell
When is isotype switching and affinity maturation typically seen?
To protein Ags. Driven by T cell dependent signals
What is increased in the secondary response?
isotype switching and affinity maturation
What do follicular B cells respond too?
Protien Ags and thus initiate T dependent Ab responses
What are T independent responses to multivalent Ag mediated by?
marginal zone B cells in the spleen and B-1 cells in mucosal site
What is another name for follicular B cells?
Recirculating B cells
What do follicular B cells migrate in Lymphoid tissues?
the B cell zones called follicles
What is the movement into lymphoid tissues guided by?
CXCL13 secreted by follicular DCs, the major stromal cell type in the follicle
How are most Ag transported to LNs?
afferent lymphatic vessels that drain into the subcapsular sinus of the LNs
Who will solube Ag interact with once they reach the B cell zone?
Directly with specific B cells
How are large Ag captured?
by resident DCs and transported inot follicles, where they can activate B cells
What are microbes and Ag-Ab complexes captured by?
subcapsular sinus macrophages which deliver ags to follicles
What Receptors do Follicular DCs have?
CR2 that allows it to present ag to follicular B cells
Where in the body might an immune complex bind in the marginal zone B cells?
The CR2 complex in the spleen
What can capture blood borne pathogens?
plasmacytoid dendritic cells and transport them to the spleen where they are delieved to the marginal B zone
What can capture polysaccharide Ags?
Mo in the marginal zone of splenic lymphoid follicles and displayed or transferred to B cells
What type of antigens are normally presented to B cells?
intact, native conformation not processed by APCs
How are small angtigens deliverd to B cells?
through afferent lymphatics via conduits
