Immunology

Question 1

What are Toll-like receptors (TLRs) and what is their function? Are they part of the innate or adaptive immune system?

Answer 1

They are pattern recgonition receptors that recognize pattern-associated molecular patterns (PAMPs); innate immune system

Question 2

Which subdivision of the immune system is germline encoded?

Answer 2

innate immune system

Question 3

Which cell of lymphoid origin is considered part of the innate immune system?

Answer 3

Natural Killer cells

Question 4

Which subdivision of the immune system achieves variation through VDJ recombination during lymphocyte development?

Answer 4

adaptive immune system

Question 5

What is the initial role of complement in the immune response?

Answer 5

some complement fragments coat bacteria, and others induce vasodilation

Question 6

What are the three main roles of complement?

Answer 6

opsonization (leading to phagocytosis), vasodilation, lysis (by recruiting bacteriolytic complement proteins)

Question 7

which innate immune cells possess the key effector function of phagocytosis?

Answer 7

neutrophils, eosinophils, macrophages

Question 8

which innate immune cells possess the key effector function of degranulation?

Answer 8

neutrophils, basophils, mast cells, eosinophils

Question 9

NK cells have enhanced specificity for what types of pathogens?

Answer 9

virus

Question 10

What is the role of dendritic cells (DCs) in T cell activation?

Answer 10

DCs ingest foreign pathogens, migrate to draining lymph nodes, and activate T cells

Question 11

An activated DC is also called a what?

Answer 11

Antigen presenting cell (APC)

Question 12

What are the main role of T helper cells (Th)?

Answer 12

to secrete cytokines, activate B cells, and activate innate cells

Question 13

What are the main effector functions of cytotixic T cells (CTL)?

Answer 13

secrete cytokines, kill infected cells

Question 14

What is the difference in pathogen specificity between Th and CTL cells?

Answer 14

Th: anti-bacterial, anti-fungal, anti-parasitic, anti-viral
CTL: anti-viral

Question 15

What are the main effector functions of antibodies?

Answer 15

neutralize (prevent infections), activate complement, activate innate cells

Question 16

Which two elements of the innate immune system allow immediate binding of pathogens?

Answer 16

complement, and PAMPs

Question 17

Which cell types carry pattern recognition receptors (PRRs)?

Answer 17

All WBCs

Question 18

What is the immediate result of PRR-mediated pattern recognition?

Answer 18

release of inflammatory cytokines and chemokines

Question 19

Which lymphoid organs are considered primary?

Answer 19

Bone marrow and thymus

Question 20

Where do developing T cells migrate to mature?

Answer 20

the thymus

Question 21

What is the main difference in antigen binding between B and T cells?

Answer 21

T cells can only recognize antigen presented by MHC; B cells can bind antigens in many forms

Question 22

MHC class I activates which type of T cell?

Answer 22

CD8+ T cells (CTL)

Question 23

MHC class II activates which type of T cell?

Answer 23

CD4+ T cells (Th)

Question 24

What are the 3 Human Leukocyte Antigen (HLA) genes associated with MHC class I?

Answer 24

HLA-A, HLA-B, HLA-C

Question 25

What types of cells present MHC class I?

Answer 25

All nucleated cells

Question 26

Which cell types present MHC class II?

Answer 26

Dendritic cells (DC), B cells, and macrophages

Question 27

What process occurs involving developing T cells in the thymus cortex?

Answer 27

Positive selection for T cell receptors (TCRs) that bind MHC (95%+ T cells destroyed at this stage)

Question 28

What process occurs involving thymocytes in the thymus medulla?

Answer 28

Negative selection of autoreactive thymocytes

Question 29

What is the immediate reaction of a macrophage to encountering a PAMP?

Answer 29

release cytokines

Question 30

In the spleen/lymph nodes, a primary follicle contains what type of cells?

Answer 30

naive B cells

Question 31

Where do the T cells reside in the lymph nodes?

Answer 31

the paracortex

Question 32

Where do the T cells reside in the spleen?

Answer 32

the periarteriolar lymphoid sheath (PALS)

Question 33

What is clonal expansion?

Answer 33

rapid growth of a cell type, usually as a triggered response

Question 34

What is the first signal required for T cell activation by DC?

Answer 34

TCR + pMHC +co-receptor (CD4 or CD8) +CD3

Question 35

What is the second signal required for T cell activation by DC?

Answer 35

costimulation (B7:CD28)

Question 36

By what cytokine do Th1 cells enhance the activity of macrophages?

Answer 36

interferon gamma

Question 37

Antigen-mediated activation of B cells induces what type of antibody response?

Answer 37

IgM

Question 38

The germinal center (spleen/lymph nodes) forms as a result of what interaction with naive B cells?

Answer 38

Th cells

Question 39

What cells are responsible for releasing antibodies?

Answer 39

plasma cells (further differentiation of activated B cells)

Question 40

What type of antibodies can activate complement?

Answer 40

IgM, IgG

Question 41

What type of antibody is responsible for activating mast cells?

Answer 41

IgE

Question 42

Where do B cells develop and mature?

Answer 42

Bone marrow

Question 43

Which region of the antibody determines the immunoglobulin isotype?

Answer 43

the constant region