Lecture 7 Flashcards
(17 cards)
Where do B cell activation, proliferation and differentiation take place?
peripheral lymphoid organs
Which chemokine receptors do naive B cells express to exit circulation?
CXCR5
Which components of the complement-coated microbial antigens do follicular dendritic cells take up?
C3b and C3d
Which complement receptor increases the avidity of the B cell to antigen?
CR2
What other co-receptor is CR2 associated with?
CD19 (intracellular cytoplasmic signaling domains)
Which chemokine receptor directs semi-activated B cell out of follicle towards T cell zone?
CCR7
What three processes are involved in B-cell differentiation?
- Ig class switching from IgM to IgG, IgA or IgE
- somatic hypermutation/affinity maturation
- generation of memory B cells
Which enzyme is required for both Ig class switching and somatic hypermutation?
activation-induced deaminase (AID)
Ig class switching replaces which parts of the antibody?
replace heavy chain constant region of expressed antibody
Define Hyper-IgM syndrome
- defective expression of CD40L on T helper cells and prevent them from providing help to B cells for Ig class switching
- resulting in high level so of IgM
affinity maturation of antibody response
B cells give rise to plasma cells that secrete higher affinity antibodies
microbial capsular polysaccharides and lipids with repeating identical units with no protein component
T-independent antigens
The spleen is a major source of which immunoglobulin?
IgM (short-lived)
Which immunoglobulins are long-lived?
-IgG (blood), IgA (mucosal), and IgE (submucosa and skin) plasma cells derived from follicular B cells
What does the presence of serum IgM antibodies to specific microbe indicate?
current microbial infection
What does the presence of microbe-specific serum IgM antibodies in absence of serum IgM antibodies indicate?
individual was previously infected by microbe and generated long-lived microbe-specific IgG plasma cells
Ig, CD19, and CD20 are surface proteins unique to which cell?
B cell
