Immunity Exam 2 Flashcards
During antigen recognition naive B cells are stimulated by antigen binding to cell surface IgM or IgD and _______________ of several B cell receptors
cross-linking
Expression of co-stimulatory molecules and cytokine receptors act as ____ in B cell activation
APC
Polysaccharides, lipids, nucleic acids are T independent. What does that mean
they are not seen by T cells
Multivalent antigen (repeated epitope) cross-links surface Ig on what kind of cells
B cells
Most proteins antigens are ___ ___________ antigens which mean they need T cell help for maximal response
T dependent
T independent antigens are most what kind of Ig response?
IgM sometimes IgG
How do T cells activate B cells
B cells present antigen and co-stimulators
activated T cells express CD40 and secrete cytokines
B cells are then activated
Do T cells and B cells bind the same epitope
no
What are haptens
a molecule that can be recognized by an antibody, but that cannot by itself induce antibody production (or T cell response)
Haptens are important in the generation of what
drug allergies
When attached to a carrier haptens become what
immunogenic, they can only be immunogenic when covalently coupled to a carrier
B cells need to __________ surface antibody
cross-link
Hapten on peptides can bind ______ and stimulate T cells
MHC
(A hapten on a carrier can stimulate T cell help by carrier-specific T cells. T cell recognizes foreign or modified peptides presented by the B cell.)
Poison Ivy reaction is a hapten-carrier reaction because urushiol is what
reactive
What happens in primary sensitization of poison ivy
sensitized T cells are produced and give rise to memory cells
What happens during second contact of poison ivy
T memory cells become activated; precipitate and inflammatory reaction and dermatitis
What happens during a sulfonamide-antibiotic allergy
reactive molecules can couple to proteins
antibodies recognize 5-membered ring
generate antibodies to the drug and T cells recognize it
T cells help induces what
more antibody production
heavy chain class switching
affinity maturation (antibody structure changes to have higher affinity for antigen)
memory B cell production
What do Ig B cells first secrete, how does this class swtich, and what happens in the decient individual
IgM first
-CD40L on T cell binds to CD40 on B cell
–CD40L deficiency have hyper-IgM
T cell cytokines determine new isotypes. What does IFN gamma cause, IL-4 cause, and TGF beta cause
IFNgamma -> IgG
IL-4 -> IgE (sometimes IgG)
TGFbeta -> mucosal tissues IgA
Isotype switching puts same ____ on a different Fc region. How does this activate the pathway
VH
Fc region recognized by Fc receptors and complement
Fc conformation changes when Ab binds to antigen
Fc conformation changes when Ab binds to antigen, so antigen-antibody complexes activate what
complement
What is the principle effector function of IgM
complement activation
What is the principle effector function of IgG
Fc receptor dependent phagocyte responses, complement activation, neonatal immunity