Host Response to Viral Infection

Question 1

What are 3 types of host immune response?

Answer 1

1. Innate immunity
2. Adaptive immunity
3. Passive immunity

Question 2

T/F: Innate immunity defenses exhibit antigen specificity and memory

Answer 2

False; do not exhibit antigen specificity or memory

Question 3

Innate immunity is the ________ line of defense against viral infection

Answer 3

First

Question 4

T/F: Innate immunity has primary physical and chemical defenses

Answer 4

True

Question 5

What are the 2 primary physical and chemical defenses of respiratory tract?

Answer 5

1. Mucociliary blanket

2. Temp. Gradient

Question 6

NK cells mediate cell death via ___________

Answer 6

Apoptosis

Question 7

One class of PRRs are ___________

Answer 7

TLRs (toll-like receptors)

Question 8

PRRs recognize ___________

Answer 8

PAMPs (pathogen specific associated molecular patterns)

Question 9

Interferons are secreted by _________ cells in response to viral infections an other stimuli

Answer 9

Somatic

Question 10

Interferons possess what 3 properties?

Answer 10

Potent antiviral, immunomodulating, and anti-cancer properties

Question 11

T/F: Interferons have virus specificity

Answer 11

False; have no virus specificity

Question 12

Who is stronger inducer of interferons? DNA or RNA viruses?

Answer 12

RNA viruses

Question 13

Why should interferons be administered by injection?

Answer 13

Because they are orally inactive

Question 14

What is IFN-α?

Answer 14

Leukocyte interferon produced in large quantities by dendritic cells

Question 15

What is IFN-β?

Answer 15

Fibroblast interferon secreted by virus infected fibroblast

Question 16

IFN-α & IFN-β are what type of interferons?

Answer 16

Type 1

Question 17

What are some roles of type-1 IFNs?

Answer 17

1. Inhibit virus replication
2. Activate NK cells
3. Increase MHC-1 expression
4. Maturation of dendritic cells
5. Stimulate memory T-cell proliferation

Question 18

Type-II interferon has INF-_____

Answer 18

IFN-γ

Question 19

What is the main function of IFN-γ?

Answer 19

Mostly immunoregulatory

Question 20

What 3 types of IFN are in type-III interferons?

Answer 20

IFN-λ1
IFN-λ2
IFN-λ3

Question 21

What is the primary function of type-III IFNs?

Answer 21

Immunoregulator

Question 22

Type-III IFNs are expressed in response to what two things?

Answer 22

1. Viral infections

2. TLRs

Question 23

Adaptive immunity includes ___________ and ____________ components

Answer 23

Humoral and cellular

Question 24

Adaptive immunity is __________ specific

Answer 24

Antigen

Question 25

Humoral immunity is mediated by Ab released from ___ lymphocytes and cellular immunity is mediated by ___ lymphocytes

Answer 25

1. B | 2. T

Question 26

Adaptive immunity stimulates _____-term memory after infection

Answer 26

Long

Question 27

Antibodies may be expressed by what two types of viral proteins?

Answer 27

1. Viral proteins on free virions | 2. Viral proteins expressed on surface of infected cells

Question 28

What does virus neutralization do?

Answer 28

Prevents virus attachment and entry into host cells; they bind to viral capsid or host envelope

Question 29

What is opsonization?

Answer 29

Coating of virions with antibodies so it is recognized and phagocytosed by macrophages and sometimes neutrophils

Question 30

What are 5 antiviral effects on antibodies?

Answer 30

1. Virus neutralization 2. Opsonization 3. Clumping of viruses 4. Activation of compliment system 5. Antibody-dependent cell-mediated cytotoxicity

Question 31

What are 4 components of cell mediated immunity?

Answer 31

1. Activation of macrophages 2. Inflammation 3. Stimulation of B lymphocytes 4. Killing of infected cells

Question 32

T/F: adaptive immunity is virus specific

Answer 32

True

Question 33

What are 9 ways viruses evade the immune system?

Answer 33

1. Antigen plasticity 2. Antigen multiplicity 3. Negative cytokine regulation 4. Down-regulation of MHC class 1 pathway 5. Inhibition of compliment activation 6. Evasion of neutralizing antibodies 7. Latency 8. Cell-to-cell spread of viruses 9. Inhibition of apoptosis

Question 34

What is antigenic plasticity?

Answer 34

Rapid changes in structure of viral antigen

Question 35

What is antigenic multiplicity?

Answer 35

Antigenic variants with little or no cross-reactivity

Question 36

What are virokines?

Answer 36

Viruses that synthesize proteins that are homologs of cytokines/IFNs

Question 37

What are viroceptors?

Answer 37

Viruses that encode proteins that are homologous to receptors for cytokines