AP3: CD

Question 1

Which feature characterizes the innate immune system - A Highly diverse receptor repertoire B Rapid response within minutes or hours after exposure C Strong immunological memory after primary exposure D Highly specific antigen recognition

Answer 1

B Rapid response within minutes or hours after exposure

Question 2

The process by which coordinated ciliary beating moves trapped microorganisms toward the mouth and nose is called the ______

Answer 2

Mucociliary escalator

Question 3

Which of the following are first line defence mechanisms - A Low pH of gastric acid B Microbiome C Natural killer cells D Lysozyme in tears and saliva

Answer 3

A B and D

Question 4

Explain the functional significance of non reactivity to self in the immune system

Answer 4

It prevents immune responses against host tissues and allows discrimination between self and foreign antigens thus avoiding autoimmune damage

Question 5

Which disease is associated with thick sticky mucus that is difficult to clear - A Primary ciliary dyskinesia B MBL deficiency C Cystic fibrosis D Autoinflammatory disease

Answer 5

C Cystic fibrosis

Question 6

The skin maintains an unfavourable environment for pathogens by having a pH of approximately ______

Answer 6

5.5

Question 7

Which of the following are cellular components of the second line of defence - A Neutrophils B Monocytes and macrophages C Dendritic cells D Intact skin

Answer 7

A B and C

Question 8

Contrast the diversity and memory of innate and adaptive immune systems

Answer 8

Innate immunity has limited receptor diversity and minimal memory while adaptive immunity has highly diverse receptors and develops long term memory after exposure

Question 9

Which antimicrobial peptide is mainly produced by Paneth cells in the small intestine - A Beta defensins B Lysozyme C Alpha defensins D Lactoperoxidase

Answer 9

C Alpha defensins

Question 10

Defensins kill pathogens mainly by disrupting the ______ of microorganisms

Answer 10

membranes

Question 11

Which Toll like receptor recognizes lipopolysaccharide on Gram negative bacteria - A TLR2 B TLR4 C TLR5 D TLR9

Answer 11

B TLR4

Question 12

Where are Toll like receptors expressed in human cells - A Cell membrane B Intracellular endosomes C Only nucleus D Platelet surface

Answer 12

A B and D

Question 13

Describe the outcome when a Toll like receptor binds to a pathogen associated molecular pattern

Answer 13

Binding activates innate immune signaling leading to cytokine production defensin release inflammation and recruitment of neutrophils

Question 14

Intracellular Toll like receptors such as TLR3 TLR7 and TLR8 mainly detect ______

Answer 14

Viruses or viral nucleic acids

Question 15

Which molecule binds antigen antibody complexes to activate the classical complement pathway - A MBL B C3b C C1q D Factor B

Answer 15

C C1q

Question 16

The synthesis of Mannan binding lectin in the liver is induced by the cytokine ______

Answer 16

IL 6

Question 17

What are the major outcomes of complement activation - A Opsonization B Recruitment of inflammatory cells C Antibody production D Pathogen lysis

Answer 17

A B and D

Question 18

Explain the mechanism and purpose of the membrane attack complex

Answer 18

Complement components C5b C6 C7 C8 and C9 assemble to form pores in microbial membranes causing osmotic lysis and pathogen death

Question 19

Which complement component acts as a bone marrow activator promoting neutrophil production - A C3a B C3b C C3e D C5a

Answer 19

C C3e

Question 20

Complement fragments C3a and C5a are described as ______ because they trigger mast cell degranulation and histamine release

Answer 20

anaphylatoxins

Question 21

Which molecules act as chemoattractants for neutrophils - A IL 8 B C3a and C5a C TNF alpha D N formyl peptides

Answer 21

A B and D

Question 22

Define diapedesis and describe the role of adhesion molecules

Answer 22

Diapedesis is the movement of leukocytes from blood vessels into tissues mediated by interactions between endothelial adhesion molecules and leukocyte integrins

Question 23

Which feature characterizes a resting blood vessel - A High integrin expression B Low endothelial adhesion molecule expression C Large endothelial gaps D High chemoattractant levels

Answer 23

B Low endothelial adhesion molecule expression

Question 24

During inflammation ______ increase vascular permeability by releasing prostaglandins of the E series

Answer 24

Neutrophils

Question 25

Which factors activate vascular endothelium locally - A IL 1 B TNF alpha C Histamine D Lysozyme

Answer 25

A B and C

Question 26

Describe the three stages of phagocytosis

Answer 26

Opsonization prepares the pathogen for recognition immune adherence binds it to phagocyte receptors and ingestion forms a phagosome inside the cell

Question 27

Which enzyme drives the respiratory burst by reducing oxygen to superoxide - A Superoxide dismutase B Myeloperoxidase C NADPH oxidase D Nitric oxide synthase

Answer 27

C NADPH oxidase

Question 28

In oxygen dependent killing myeloperoxidase uses hydrogen peroxide and chloride ions to produce ______

Answer 28

Hypochlorous acid HOCl

Question 29

Which antimicrobial molecules are preformed in neutrophil granules - A Lysozyme B Lactoferrin C Alpha defensins D Nitric oxide

Answer 29

A B and C

Question 30

Explain how phagocytosis minimizes host tissue damage

Answer 30

Microbes are destroyed inside the phagolysosome where toxic molecules are confined preventing injury to surrounding host tissue

Question 31

Autoinflammatory diseases are best described as - A Hyperactive adaptive immunity B Genetic mutations affecting innate immune cells C Excess IgE production D Defective ciliary function

Answer 31

B Genetic mutations affecting innate immune cells

Question 32

When microbes are too large to phagocytose immune cells release antimicrobial molecules through ______

Answer 32

exocytosis

Question 33

Which cells can use exocytosis as a killing mechanism - A Eosinophils B Neutrophils C Macrophages D Platelets

Answer 33

A B and C

Question 34

Describe the role of platelets in innate immunity

Answer 34

Platelets express Toll like receptors release cytokines interact with complement proteins and enhance neutrophil extracellular trap formation

Question 35

Which cell type produces most soluble CD40 ligand

Answer 35

A Activated platelets

Question 36

Interactions between CD40 and CD40L are important for signaling in both the ______ and ______ immune systems

Answer 36

innate and adaptive

Question 37

Which molecular interactions mediate platelet neutrophil binding - A CD40L with CD40 B P selectin with PSGL 1 C GPIb with alpha M beta 2 integrin D TLR4 with LPS

Answer 37

A B and C

Question 38

Why did the patient Dorothy develop recurrent respiratory infections

Answer 38

She had Mannan binding lectin deficiency impairing lectin complement activation and pathogen clearance

Question 39

Which complement pathway is triggered by pathogen surfaces with low sialic acid - A Classical pathway B Lectin pathway C Alternative pathway D MBL pathway

Answer 39

C Alternative pathway

Question 40

In autoinflammatory diseases mutations often increase levels of ______ and ______ cytokines

Answer 40

TNF and IL 1B