Adaptive Immune System 1) Leukocytes

Question 1

What do you lose in HIV?

Answer 1

T cells

Question 2

Where do lymphocytes develop and where do they mature?

Answer 2

bone marrow, mature in thymus

Question 3

What are the 2 types of T cells?

Answer 3

helper and killer

Question 4

How does diversity arise in lymphocytes?

Answer 4

random re-arrangement of segmented antigen receptor genes during lymphocyte development

Question 5

is antigen presenting required for small linear protein fragments?

Answer 5

Yes (not for intact macromolecules)

Question 6

What are the immune system’s mechanism for displaying peptide antigens to T cells?

Answer 6

MHC molecules (also called HLA)

Question 7

What do secondary lymphoid tissues act as a hub for?

Answer 7

lymphocyte activation

Question 8

What capture opsonised antigens?

Answer 8

Follicular dentritic cells in lymphoid follicles

Question 9

What transport antigens to lymph nodes?

Answer 9

migrating dendritic cells

Question 10

What 2 signals are required for full activation of lymphocytes?

Answer 10

antigen receptor engagement

co-stimulatory signals

Question 11

What are T cell dependent antigens?

Answer 11

protein antigens

co-stimulation provided by activated CD4+ helper T cells

Question 12

What do activated T cells produce and express?

Answer 12

A cytokine (interleukin 2), and then express the IL2 receptor which drives mitosis and replication of the activated T cells

Question 13

What do clonally expanded CD4+ cells differentiate into?

Answer 13

Helper T cells (Th cells)

Question 14

What do Th cells secrete?

Answer 14

cytokines that affect the function of other immune cells

Question 15

What does IL2 activate?

Answer 15

CD8+ T cells

Question 16

What do IL4 and IL5 and IFNy activate?

Answer 16

B cells

Question 17

What does IFNy also activate?

Answer 17

macrophages

Question 18

How do Th cells help macrophages?

Answer 18

stimulate macrophage effector functions by hyperactivating them into much better killing machines:
Increased reactive oxygen species production
Increase inflammatory cytokine production
Increased expression of MHC molecules and co-stimulators such as B7

Question 19

What does binding of the Th cell, IFNy and IFNy receptor on surface of a macrophage do?

Answer 19

stimualtes intracellular signalling events resulting in enhanced killing

Question 20

What main 2 proteins do cytotoxic T cells employ to directly attack and destroy?

Answer 20

granzymes and perforin

Question 21

What does perforin do?

Answer 21

form holes/pores in surface membrane of target cell allowing granzymes to enter

Question 22

What do granzymes do?

Answer 22

induce target cells to undergo apoptosis

Question 23

What do CTLs also secrete?

Answer 23

Fas ligand and Cytokines

Question 24

How do Th cells help B cells?

Answer 24

Th cell secreted cytokines bind to B cells

Th cell surface molecules bind macrophage and B cell surface receptors

Question 25

What B cell maturation events occur during response to T cell dependent antigens?

Answer 25

class switching
somatic hypermutation

Question 26

What are the 3 major helper T cell effector subtypes?

Answer 26

Th1, Th2 and Th17

Question 27

What type of memory cells are there?

Answer 27

Memory Th cells
Memory CTLs
Memory B cells