21 - Viral Pathogenesis and Host Immune Defense (Stapleton)

Question 1

viremia

Answer 1

virus circulating in the blood

Question 2

killing of cells by viruses

Answer 2

direct

indirect-host immune response kills infected cells

Question 3

viral infection cellular outcomes

Answer 3

noncytolytic infection
cytolytic infection
transformation
abortive infection

Question 4

noncytolytic viral infection

Answer 4

active replication, little effect on cell physiology

viral latency

Question 5

cytolytic viral infection

Answer 5

apoptosis, necrosis, autophagy
altered cell morphology (inclusion bodies, syncytium formation)
altered cell physiology

Question 6

abortive viral infection

Answer 6

entry of virus into cell that cannot support viral replication

Question 7

transformation infection

Answer 7

causes cancer

Question 8

DNA transformation cancer

Answer 8

HPV-cervical cancer
Herpes virus-burkitt’s lymphoma, HHV8
HBV-liver cancer, chronic inflammation

Question 9

RNA transformation cancer

Answer 9

retrovirus-HIV

HCV-HCC

Question 10

direct cancer formation from viruses

Answer 10

latent infection cause short lived cells to prolong life

disrupt host cell gene infection

Question 11

indirect cancer formation from viruses

Answer 11

replication causes chronic inflammation
chronic inflammation causes neoplaisa
reduced immune function, and lower immune surveillance

Question 12

detection of virus

Answer 12

not visible by light microscopy
exclude bacteria, supportive care
tissue, swab, blood, or exudates
detect virus in cell culture
viral antibody detection

Question 13

molecular detection of viruses

Answer 13

DNA-PCR

RNA-RT-PCR

Question 14

early symptoms of viral infection suggest

Answer 14

direct viral cytotoxicity

Question 15

late symptoms of viral infection suggest

Answer 15

disease mediated by immune response

Question 16

outbreak

Answer 16

community

Question 17

epidemic

Answer 17

region

Question 18

pandemic

Answer 18

worldwide

Question 19

iceberg concept

Answer 19

most exposure to virus does not result in disease

severe disease and death are rare

Question 20

innate immune response

Answer 20

first line of defense
innate immune cells recognize pathogen recognition receptor
phagocytic cells ingest and produce cytokines/chemokines
APC process antigen into peptides
peptides start effector cells to detect problem with infected cells

Question 21

PRR bind what

Answer 21

pathogen associated molecular patterns (PAMPs)

Question 22

RIG I

Answer 22

bind dsRNA

turn on interferon genes

Question 23

steps to control viral infection

Answer 23

1-PRR recognize virus
2-PRR increase IFN a and b
3-cells release IFN that bind IFNa receptors
4- increase IFN stimulated genes
5-ISG inhibit replication cycle
6-IFN block virus replication

Question 24

NK cells

Answer 24

identify cell surface changes and kill cells

Question 25

monocytes/macrophages

Answer 25

phagocytose dying cells | remove infected cells

Question 26

Type 2 IFN

Answer 26

IFN-y important in adaptive immune response made my NK and T cells stimulates production of effector and memory T cells

Question 27

adaptive immunity uses

Answer 27

CD4 and CD8 T cells

Question 28

CD4 T cells

Answer 28

``` antigen specific response CD4T helper control intracellular pathogens respond to MHC class 2 produce lymphokines, cytokines, and chemokines to stimulate B and CD8 response ```

Question 29

CD8 T cells

Answer 29

``` cytotoxic recognize peptides on MHC class 1 kill cells with Fas pathway and perforin produce cytokines clear most viral infections with CD8 ```

Question 30

acquired immune defense

Answer 30

IgM, A, G, E neutralization opsonization cell lysis

Question 31

memory cells

Answer 31

antigen specific long lived rapidly expand with reinfection

Question 32

memory CD8

Answer 32

kill infected cells

Question 33

memory b cells

Answer 33

produce antibodies

Question 34

which antibody comes first

Answer 34

IgM then IgG

Question 35

viral evasion mechanisms

Answer 35

elude immune detection damage immune system viral counter defenses

Question 36

ways virus elude immune detection

Answer 36

``` antigen variation restrict gene expression reduce MHC cell surface expression infect anatomic sites poorly accessible to immune system establish immunologic tolerance ```

Question 37

ways virus damages immune system

Answer 37

damage 1+ arm of immune system | immune suppression

Question 38

viral counter defenses

Answer 38

reduce activation express proteins that block IFN or complement cytokine release favoring spread cytokine that block immune response