Flashcards in Immuno p.203-207 Deck (55)
Name all antigen presenting cells:
B cells, microphages, dendritic cells
How many signals are required for T cell activation, B cell activation, and class switching?
What is a “Costimulatory signal”?
interaction of B7 and CD28 (signal 2).
MHC II presents Ag to which CD cells?
CD4+ cell which are recognized by TCR
MHC I presents Ag to which CD cells?
Tc (CD8+) cell
5 steps in Naive T-cell activation:
1. Dendritic cell samples and processes antigen.
2. Dendritic cell migrates to the draining lymph node.
3. Antigen is presented on MHC II, MHC I
4. “Costimulatory signal”
5. Th cell activates and produces cytokines. Tc cell activates and is able to recognize and kill virus infected
What is the first signal in B-cell activation and class switching?
Foreign antigen is presented on MHC II and recognized by TCR on Th cell
2nd signal of B-cell activation and class switching involves ----- receptor on B cell binds ----- on Th cell
CD40, CD40 ligand (CD40L)
4 steps of B-cell activation and class switching:
1. Th-cell activation.
2. B-cell receptor–mediated endocytosis; foreign antigen is presented on MHC II and recognized by TCR on Th cell (signal 1).
3. CD40 receptor on B cell binds CD40 ligand (CD40L) on Th cell (signal 2).
4. Th cell secretes cytokines --> B cell activates and undergoes class switching, affinity maturation, and antibody production.
--- region of IgM and IgG fixes complement.
--- region consisting of light (L) and heavy (H) chains recognizes antigens.
In Digoxin toxicity what part of the antidote given targets Digoxin?
Fab (Digoxin immune Fab)
Which part of an Ab has carbohydrate side chains?
T or F? Fab has only 1 antigenic specificity expressed per B cell and has a carboxy terminal.
F. Fc has a carboxy terminal.
Which region determines isotypes like IgM or IgD?
Antibody diversity is generated by random recombination of -- or --- genes
What is the function of TdT during Ab diversification?
Terminal deoxynucleotidyl transferase Adds nucleotides to DNA during recombination.
Which lymphoid neoplasm has a TdT+ marker?
Acute lymphoblastic leukemia/lymphoma
(marker of pre-T and pre-B cells),
Mature B cells expresson which 2 immunoglobulins on their surfaces?
IgM and IgD
Isotype switching of Ig is mediated by what 2 components?
cytokines and CD40L
Which Ig has the lowest concentration in serum?
Most abundant Ig isotype in serum?
Ab that is a monomer in circulation or dimer (when secreted?
IgA is produced in GI tract by --- and protects against gut infections.
Main antibody in 2° (delayed) response to an antigen?
Ab that cross-links when exposed to allergen, mediating immediate (type I) hypersensitivity?
What shape is IgM on B-cells?
Monomer on B cells
Ab produced in the 1° (immediate) response to an antigen/
Why do vaccines often require boosters and adjuvants?
Because Ag lacking a peptide component (e.g., lipopolysaccharides from gram-negative bacteria)
cannot be presented by MHC to T cells.