B cell activation and antibody production Flashcards
IFN-gamma induces B cell switching to what?
IgG (Th1)
Isotype switching involves the changing of what portion of an antibody?
Constant region of Heavy Chain
IL-4 induces switching to what?
IgE (Th2).
Describe the response to helminths.
Driven by IgE which participate in eosinophil and mast cell mediated elimination of the helminths.
CD40 induces what enzyme that is crucial for isotype switching and affinity maturation?
Activation induced deaminase (AID).
When is affinity maturation observed?
Observed only in Ab responses to T-dependent protein Ags.
Describe the process of affinity maturation.
During the germinal center reaction, somatic hypermutation of Ig V genes and selection of B cells with high-affinity Ag receptors results in the production of Abs with high affinity for Ag.
What are the two types of plasma cells and what are their characteristics?
1) Short lived plasma cells- generated during T-independent responses, generally found in secondary lymph organs and peripheral non-lymphoid tissue.
2) Long lived plasma cells- generated in T-dependent response to protein Ags, generated by signals from BCR and IL-21 via a stage of their precursors called plasmablasts.
What Ags will stimulate T-independent responses?
Polysaccharides and lipids. Mainly IgM is produced with lower affinity.
What Ags stimulate T dependent response?
proteins.
What is the major mechanism of host defense against infections by encapsulated bacteria?
Humoral immunity.
