10) MHC

Question 1

3 main Ag recognition molecules in the immune system

Answer 1

• TCR
• sIg
• MHC

Question 2

2 main functions of MHC in T-cell response

Answer 2

• establish library of T-cells during development
• activation of mature T cells

Question 3

2 best known MHC molecules

Answer 3

• human (HLA)
• mouse (H2)

Question 4

MHC similar to Ig

Answer 4

MHC I

Question 5

divided into 3 independent loci (A, B, C)

Answer 5

MHC I

Question 6

3 variable portions of MHC I

Answer 6

𝛼1
𝛼2
𝛼3

Question 7

invariant portion of MHC I

Answer 7

β2 microglobulin

Question 8

MHC I AA length

Answer 8

8-9

Question 9

binds to β2 microglobulin of MHC I

Answer 9

CD8

Question 10

each individual expresses —- MHC I molecules

Answer 10

6

(2 HLA-A, 2 HLA-B, and 2 HLA-C)

Question 11

subdivided into DP and DR

Answer 11

coding region for MHC II

Question 12

consists of parallel transmembrane 𝛼 and β chains

Answer 12

MHC II

Question 13

MHC II AA length

Answer 13

12-25

Question 14

binds to invariant β region of MHC II

Answer 14

CD4

Question 15

MHC II always expressed on…

Answer 15

B cells
dendritics
thymic epithelials

Question 16

can be induced to express MHC II

Answer 16

T-cells
macros

Question 17

group of complement factors found in serum

Answer 17

MHC III

Question 18

what kind of Ag does MHC II present?

Answer 18

exogenous
internalized by endocytosis or phagocytosis

Question 19

what kind of Ag does MHC I present?

Answer 19

endogenous
synthesized within the cell

Question 20

MHC — presents antigens found in vaccines with a non-infectious viral particle

Answer 20

II

Question 21

parameters to consider when trying to elicit an immune response

Answer 21

• amount of Ag
• timing of exposure
• route of entry

Question 22

immunogenicity depends on…

Answer 22

• complexity of Ag/more epitopes
• foreign
• large enough

Question 23

added to enhance immunogenicity of vaxx

Answer 23

adjuvant

Question 24

time before Ab is detectable in serum

Answer 24

latent phase
(1-2 weeks)

Question 25

production and degradation of Ab reach equilibrium

Answer 25

steady state

Question 26

anamnestic response

Answer 26

secondary response

Question 27

differences in secondary phase

Answer 27

• lag phase shorter
• Ab production greater
• Ab production continues for longer
• more IgG than IgM

Question 28

cell cooperation

Answer 28

Ab production requires cooperation between 2 lymph types
(irradiated mouse experiment)

Question 29

irradiated mice with/without immune response

Answer 29

WITH:
- given spleen cells
- given BM + thymus cells

WITHOUT:
- given BM cells
- given thymus

Question 30

main 2 roles of accessory cells (macros) in inducing immune response

Answer 30

• trap and concentrate Ag
• process and present Ag

Question 31

NOT activated by free Ag

Answer 31

T -cells

Question 32

process of Ag processing

Answer 32

• protein Ag enters cell (endo or phagocytosis)
• vacuoles merge with lysosomes, which have degradative enzymes
• peptides cut to 8-20 AAs
• immunodominant peptides lead to T-cell activation

Question 33

T-cell receptor complex that requires CD4 to stabilize affinity

Answer 33

TCR-CD3

Question 34

2 requirements for activation of T-cells

Answer 34

• engagement of receptors
• second signal (IL-1)

Question 35

main cytokine serving as a second signal for T-cell activation

Answer 35

IL-1

Question 36

happens first as T-cells are activated

Answer 36

• membrane phospholipids break down
• phosphorylation of intracellular proteins
• lymphokines secreted

Question 37

cytokines involved in B-cell differentiation to active plasma cells

Answer 37

IL-4
IL-5

Question 38

T-independent antigens

Answer 38

Ag capable of activating B-cells to product Ab in the absence of T helpers

Question 39

properties of T-independent Ag

Answer 39

• large, polymeric
• multiple, repeating antigenic determinants
• generate primarily IgM
• do NOT give rise to memory
• macros seem to be required