5.1 Adaptive Immune Response I

Question 1

Different types of APCs

Answer 1

Macrophages
Dendritic cells
Langerhan cells
B-lymphocytes

Question 2

Dendritic cells present pathogen to what cell & function

Answer 2

Naive T cells
Function: T-cell response against most pathogens

Question 3

Langerhans cells present pathogens to what cells & function

Answer 3

Naive T cells
Function: T-cell response against most pathogens

Question 4

Macrophages present pathogen to what cell & function

Answer 4

Effector T cell
Function: Phagocytic activities

Question 5

B cells present pathogen to what cell & function

Answer 5

Effector T cells
Function: Antibody/humoral response

Question 6

Naive T cells

Answer 6

T cells that have not previously encountered the antigen

Question 7

Effector T cells

Answer 7

T cells that have previously encountered the antigen and are capable of performing effector functions during an immune response

Question 8

Features of APCs

Answer 8

Strategic location
Diversity in pathogen capture mechanisms
Diversity in pathogen sensors (PRR)
-extracellular, intracellular

Question 9

Extracellular pathogens include

Answer 9

Bacteria
Fungi
Protozoa

Question 10

Describe the exogenous pathway

Answer 10

1. Microbes (ECM) captured via phagocytosis
2. Degraded into small peptides in endsome
3. Vesicles fuse with other vesicle containing MHC class II molecules
4. Formation of peptide-MHC class II complex

Question 11

The exogenous pathway only occurs in what type of cell?

Answer 11

APCs

Question 12

Describe the endogenous pathway

Answer 12

1. Viral protein present in cytoskeleton
2. Marked for destruction by proteasome
3. Antigenic peptide (generated by proteasome) is transported to ER where they enter through TAP1/2
4. Formation of peptide-MHC class I complex

Question 13

The endogenous pathway occurs in what type of cell

Answer 13

All cell types

Question 14

What is the difference between the exogenous and endogenous pathway

Answer 14

Exogenous: APCs presents peptides of ECM to CD4+ T cells (class II)

Endogenous: APCs and non-APCs present peptides from ICM to CD8+ (class I)

Question 15

Clinical importance of MHC molecules

Answer 15

1. Host can deal with variety of microbes (genetic polymorphism)
2. No two individual have the same set of MHC molecules
3. Different susceptibilities to infections

Question 16

Types of MHC class I molecules

Answer 16

HLA-A
HLA-B
HLA-C

Question 17

Types of MHC Class II molecules

Answer 17

HLA-DP
HLA-DQ
HLA-DR

Question 18

Role of APCs

Answer 18

Sense, Capture, Process, Present the pathogen

Question 19

Key features of MHC molecules

Answer 19

1. Co-dominant expression (MHC class 1 and 2 co-expressed)
2. Polymorphic genes (diff. individuals present and respond to diff. microbes)
3. Presentation of microbial peptides

Question 20

Where are MHC class I molecules expressed

Answer 20

All nucleated cells

Question 21

Where are MHC class II molecules expressed

Answer 21

APCs

Question 22

Examples of APCs

Answer 22

Dendritic cells
Macrophages
B cells

Question 23

How are microbes presented by MHC molecules

Answer 23

Peptide binding cleft (variable region with highly polymorphic residues)

Broad specificity (many peptides presented by the same MHC molecule)

Responsive T cells

Question 24

Different HIV antigens

Answer 24

Cell surface proteins: gp120, gp41
Gag proteins: p24, p17, p6

Question 25

What features do long-term non progressors of HIV patients have

Answer 25

MHC class I molecules that corresponds to the region of a virus that doesn’t mutate.
-able to attack it regardless of how many times HIV virus is mutated

Question 26

Clinical conditions with MHC molecules

Answer 26

-Organ transplant rejection (HLA molecules mismatch between donor and recipient)

-Autoimmune disease