cellular immune response (week 2 ppt)

Question 1

TCR

Answer 1

-recognizes pieces of antigens
-antigenic peptides are presented to TCRs by APCs (Bcells, macros, dens)

Question 2

BCR

Answer 2

-immunoglobulin molecule attached to the membrane of B cell
-co stimulation is CD40 on T cells

Question 3

plasma cells

Answer 3

mature B cells with high affinity antibodies

Question 4

multiple myeloma

Answer 4

malignant clone of plasma cells & diagnosed by SPEP

Question 5

TCR composition

Answer 5

-heterodimers
-alpha beta or gamma delta

Question 6

distinguish between Th and Tc cells

Answer 6

by their cluster of determination (CD)
-CD4 or CD8

Question 7

TCR function

Answer 7

-respond to MHC
-respond to antigen

Question 8

TCR binding affinity

Answer 8

-extremely low
-co-receptors and adhesion molecules improve avidity
-CD4 & CD8 improve TCR sensitivity 100 fold

Question 9

TCR signaling

Answer 9

-intracytoplasmic region is too short for signaling
-CD3 gamma, zeta, epsilon or sigma needed

Question 10

BCR antigen presentation

Answer 10

presents processed antigens to Th cells

Question 11

TCR antigen signaling

Answer 11

co-receptor: CD40 on B cell & CD40L on T cell

Question 12

clonal expansion in the lymph nodes

Answer 12

1. pairs of B and Th cells move to cords: clonal expansion & IgM B cells
2. return to primary follicle. secondary focus of B & T cell expansion
3. germinal centers: isotype switching, affinity maturation & memory B cells

Question 13

follicular DCs

Answer 13

store intact antigens on their surface
-maturation of B cells

Question 14

macrophages

Answer 14

subcapsular sinus
-minimal phagocytic activity
-capture & store osponized antigens
medullary sinus
-phagocytic
-filter lymph for pathogens & antigens

Question 15

T cell activation

Answer 15

-TCR + MHC/peptide complex
-CD28 & B7 (CD80)
-cytokines
increased proliferation and cytokine secretion

Question 16

activated T cells increase production of:

Answer 16

-CD25
-high affinity IL-2
-positive feedback -> T cell proliferation

Question 17

where do T cells differentiate?

Answer 17

secondary lymphoid tissues
-differentiate into effector cells and memory cells
-Th cells become cytokine secretors

Question 18

cytotoxic T cells

Answer 18

-CD8+ & are generated in the thymus
-CD8 is dimeric (alpha and beta chain)
-CD8+ T cells bind MHCI
-immune defense against intracellular pathogens (viruses & bacteria)

Question 19

Tc cell killing mechanisms

Answer 19

-secrete TNF-alpha & IFN-gamma
-cytotoxic granules (perforin)
-fas/fasL interactions. T cells express fasL on their surface and bind fas on target cell

Question 20

regulatory T cells

Answer 20

-CD4+ & CD25+
-FoxP3 transcription factor
-suppress the immune system: IL-10, TGF beta, IL-35