I6: I

Question 1

Innate and adaptive immunity act in concert to produce which primary physiological response

Answer 1

B. Inflammatory response

Question 2

The recruitment of effector memory T and B lymphocytes to sites of infection is dependent on factors released by ______ immune cells

Answer 2

innate

Question 3

Which of the following are examples of interactions between the innate and adaptive immune systems

Answer 3

A B C D

Question 4

Explain why the classical complement pathway is only operative in an immune individual

Answer 4

The classical pathway is triggered by immune complexes consisting of antigens bound to specific antibodies IgG or IgM. These antibodies only exist after previous exposure to the pathogen therefore the pathway operates mainly in immune individuals.

Question 5

Which complement activation pathways are operative in a non immune person

Answer 5

C. Alternative and MBL

Question 6

The classical complement pathway is described as being ______ efficient than the alternative and MBL pathways

Answer 6

more

Question 7

The C1 complex of the classical pathway is composed of which subunits

Answer 7

B. C1q C1r C1s

Question 8

Describe the molecular trigger that activates C1 esterase activity in the classical pathway

Answer 8

Activation occurs when IgG or IgM antibodies bind to a microorganism. The Fc region changes conformation and is recognised by the C1 complex which then acquires C1 esterase enzymatic activity.

Question 9

C1 esterase sequentially cleaves ______ and ______ to generate the components of the C3 convertase

Answer 9

C4 and C2

Question 10

What is the molecular formula for the C3 convertase of the classical pathway

Answer 10

B. C4b2a

Question 11

Which of the following are pro inflammatory mediators generated during classical complement activation

Answer 11

A B C

Question 12

The membrane attack complex MAC is composed of complement components ______

Answer 12

C5b 6 7 8 and 9

Question 13

Which complement component induces neutrophil production in bone marrow

Answer 13

C. C3e

Question 14

Contrast the roles of C3a and C5a versus C3b in the complement system

Answer 14

C3a and C5a act as anaphylatoxins that promote inflammation through chemotaxis and diapedesis. C3b acts as an opsonin coating pathogens to promote phagocytosis by immune cells.

Question 15

The membrane attack complex MAC is also referred to as the ______ ______ ______ complex

Answer 15

cell wall attack

Question 16

Which of the following are major opsonins of the immune system

Answer 16

A B C

Question 17

Describe the interaction between antibodies and phagocytes during opsonisation

Answer 17

IgG antibodies bind to microbial surfaces. Phagocytes recognise the Fc region using Fc receptors especially Fc gamma RI which activates phagocytosis of the microbe.

Question 18

Which receptor on phagocytes recognises microbes coated with IgG

Answer 18

B. Fc gamma RI

Question 19

Toll like receptor activation on epithelial cells macrophages and mast cells results in release of ______ ______ and ______

Answer 19

vasoactive amines chemokines cytokines

Question 20

Which innate cytokines activate vascular endothelium to recruit lymphocytes

Answer 20

A B

Question 21

What is the fate of a small fraction of T and B cells after infection resolves

Answer 21

C. Become memory cells

Question 22

How does the innate immune system orchestrate recruitment of effector lymphocytes

Answer 22

Innate cells detect microbes using Toll like receptors and release cytokines chemokines and histamine. These activate vascular endothelium allowing T and B cells to migrate to the infected tissue.

Question 23

The cytokine primarily responsible for differentiation of naive T cells into Th1 cells is ______

Answer 23

IL12

Question 24

Which innate immune cell is the major source of IL12

Answer 24

C. Macrophage

Question 25

Functions of IL12 in immune responses include

Answer 25

A B C D

Question 26

IFN gamma stimulates macrophages to produce ______ and ______ to kill pathogens

Answer 26

nitric oxide and reactive oxygen species

Question 27

Effects of interferon gamma include

Answer 27

A B C

Question 28

Which antibody classes are induced by IFN gamma after B cell activation

Answer 28

B. IgG2a and IgG3

Question 29

Explain how IFN gamma enhances adaptive immunity through antigen presenting cells

Answer 29

IFN gamma increases expression of MHC class II on APCs and MHC class I on many cells improving antigen presentation and activation of T cells.

Question 30

Parasites stimulate mast cells to release ______ which promotes a Th2 response

Answer 30

IL4

Question 31

A Th2 cytokine environment promotes production of which antibody class

Answer 31

C. IgE

Question 32

Components involved in a Th2 response include

Answer 32

A B D

Question 33

Describe the Th2 pathway differentiation process

Answer 33

Parasite recognition triggers IL4 release from innate cells. Naive T cells differentiate into Th2 cells which produce IL5 and IL4 promoting eosinophil recruitment and IgE production.

Question 34

Which cytokine recruits eosinophils in the Th2 pathway

Answer 34

C. IL5

Question 35

C4b2a functions as the ______ ______ in the classical complement pathway

Answer 35

C3 convertase

Question 36

The subunits C1r and C1s belong to which complex

Answer 36

C. C1 complex

Question 37

Processes facilitating leukocyte migration include

Answer 37

A B

Question 38

Summarize the cooperation of innate and adaptive immunity using opsonisation

Answer 38

Adaptive antibodies coat microbes and innate phagocytes recognise the Fc region via receptors allowing efficient pathogen ingestion and destruction.

Question 39

What is the primary role of C3a and C5a in inflammation

Answer 39

C. Chemotaxis and diapedesis

Question 40

Toll like receptors on macrophages and mast cells interact with ______ to trigger cytokine release

Answer 40

microorganisms

Question 41

Consequences of macrophage activation by IFN gamma include

Answer 41

A B C

Question 42

Which cells produce IFN gamma in the Th1 pathway

Answer 42

B. Th1 cells and NK cells

Question 43

The C5 convertase of the classical pathway is ______

Answer 43

C4b2a3b

Question 44

How do IL12 and IL4 orchestrate adaptive immune responses

Answer 44

IL12 drives Th1 cellular immunity while IL4 drives Th2 humoral immunity allowing the immune system to tailor responses to different pathogens.

Question 45

Which molecule is a major opsonin along with IgG

Answer 45

B. C3b