Ch 4 Adaptive Immunity

Question 1

T-cell Differentiation

Answer 1

1. precursor leave BM, thymus (thymocyte)
2. chemokines drive to cortex
3. rearrangement of T cell receptor (TCR) genes for beta chain

Question 2

Double Negative thymocyte

Answer 2

lack CD, TCR genes chromosome 7, express function beta chain, Double positive

Question 3

Double positive thymocyte

Answer 3

TCR alpha chain rearrangement, both CD4/8+,

Question 4

CD3/TCR Complex

Answer 4

alpha an beta chain recognise antigens, three chain pairs help intracellular signalling after TCR bind to antigen

Question 5

Positive Selection

Answer 5

Thymocyte encounter stromal cells (expresses MHC class I/II) in cortex, high affinity/no bind die, bind moderately to I (CD8) to II (CD4) mature

Question 6

Single-Positive stage

Answer 6

negative selection, strong TCR binding die, corticomedullary region and medulla

Question 7

Mature T cell

Answer 7

leave thymus, circulate bloodstream/lymphatics for APC, recognise then activated, cytokines for Th and Tc

Question 8

B cell Differentiation

Answer 8

1. BM, stromal cells
   Development of mature immunocompetent B cells
   Activation of B cells by antigen
   Differentiation of activated B cells into antibody-producing plasma cells

Question 9

Progenitor-B cells CD10/19

Answer 9

rearrange B cell receptor genes, The cells must successfully rearrange one set of heavy-chain genes to become pre-B cells

Question 10

Precursor-B cells CD20

Answer 10

Heavy μ chains of IgM class accumulate in cytoplasm, Combine with short Ig-α and Ig-β chains to form a pre-B cell receptor (pre-BCR) on the B-cell surface,

Question 11

immature CD21/40

Answer 11

Pre-BCR is replaced with a functional BCR containing two light chains and two heavy chains of the IgM class

Question 12

mature B cell CD19-21,40

Answer 12

in spleen, split into follicular or marginal zone, Exhibit cell surface IgM and IgD, Surface immunoglobulins provide activating
signal to B cells when contact with antigen
occurs

Question 13

Follicular B cells

Answer 13

recirculate, Migrate to lymph nodes and other secondary organs

Question 14

Marginal-zone B cells

Answer 14

remain in spleen, Respond quickly to bloodborne pathogens

Question 15

Plasma cell CD138

Answer 15

bone marrow and peripheral lymphoid organs, Abundant cytoplasmic Ig but little or no surface Ig

Question 16

Th1 cell

Answer 16

Produce IFN-g, IL-2, TNF-β, Activate Tc and macrophages to fight intracellular pathogens in cell-mediated immunity

Question 17

Th2 cell

Answer 17

Produce interleukins 4, 5, 6, 9, 10, 13, Help B cells produce antibodies, Promote clearance of extracellular parasites and have a role in allergy

Question 18

Th17 cell

Answer 18

Produce IL-17 and IL-22
* Recruit granulocytes to fight bacterial infections
* May be associated with pathology in some
diseases

Question 19

Treg cell

Answer 19

Have CD4 and CD25 ,Suppress the immune response to self-antigens and harmless antigens, Secrete inhibitory cytokines to inhibit proliferation of other T-cell populations

Question 20

B cell Response to T-dependent
antigens

Answer 20

Require the help of Th Can switch from production of IgM to another antibody class (e.g., IgG), Affinity of BCR increases during the immune response

Question 21

B cell Response to T-independent antigens

Answer 21

Do not involve Th Polysaccharides with many repeating units cross-link BCRs. Only IgM is produced. Memory is not
generated.