9.3 - poxvirus

Question 1

what family of viruses is poxvirus from

Answer 1

family of large dsDNA

- can infect insects, animals, humans

Question 2

egs of poxviruses

Answer 2

small pox (varoila virus ), moonkey virus,

Question 3

what is small pox

Answer 3

pus filled lesions on the skin

Question 4

how to get small pox from the infected person

Answer 4

direct contact with the infected person

- very contgaoius

Question 5

how does smallpox vaccine work and stages of it to gain immunity

Answer 5

• dip the needle in the vaccinia virus
• jab the arm
• strong immunological response to the virus
• lesion formed then scab formed after days
• scab falls and forms a scar
• immunity produced

Question 6

why does the vaccine work against smallpox

Answer 6

• the vaccine contains vaccinia virus which is similar to the smallpox virus
• vaccinia gives a strong immune response but doesn’t kill the cells

Question 7

is there transmission between humans and animals

Answer 7

no only human to human

Question 8

structure of vaccinia

Answer 8

• enveloped
• dumbbell shape
• has 2 proteinacaeous structures which are lateral bodies
• flank core
• membrane

Question 9

what familt is vaccinaia part of

Answer 9

nucleocytoplasmic large DNA viruses

Question 10

functions of core and lateral bodies

Answer 10

contain proteins important for processes in the virus

- like core has proteins for transcription

Question 11

where does the replication vaccinia takes place in the host cell

Answer 11

cytoplasm

-use host organelles like golgi, ER

Question 12

how many forms does vaccinaia make and what are they

Answer 12

2 forms of this virus

• mature virions
• extracellular virions

Question 13

how does vaccinaia enter the cells

Answer 13

binds to glycoproteins and trigger endocytosis of macropinocytosis
- gets inside of macropinosomes

Question 14

what is macropinocytosis

Answer 14

engulfment and uptake process of large amounts of fluids and membranes

Question 15

how does the virus leave the macropinosome and what does it leave behind

Answer 15

by fusion

- membrane which is then degraded

Question 16

what is dispered into the cytoplasm after virus leaving the macripinosome

Answer 16

core and the lateral bodies in

Question 17

stages of vaccinia virus replication

Answer 17

1. early gene replication happen where it makes proteins for DNA replication of the virus
2. viral genome uncoated
3. viral genome replicated
4. replication for intermediate and late gene expression

Question 18

how does mature virions (MVs) come about after the repilcation

Answer 18

cresents (open membrane) grow contaning viral factory and proteins > immature virions

• go through maturation like cleavage and structural changes

becomes infectious

Question 19

how does the vaccinia exit the cell

Answer 19

MV transported to golgi to be wrapped in the golgi cisternae

• then transported to cell surface
• virus fuses with the plasma membrane

Question 20

how does the virus get to other cells

Answer 20

actin rails push the virus to surrounding cells

Question 21

how does the virus evade the immune system

Answer 21

• molecular mimicry > mimics the self AGs so IS not activated
• inhibition or activation of cell processes

Question 22

alternative immune evasion strategies

Answer 22

• apoptotic mimicry
  extracellular enveloped virions (EEVs)
  -lateral bodies

Question 23

what does dead cell and cell debris express on their surfaces

Answer 23

PS - phosphatidylserine
- signal to engulf the cells
all cells have this receptor

Question 24

how does the virus use apoptotic mimicry

Answer 24

the virus is enriched in PS layer and expresses PS receptors

• tricks the cells to take it up as debris
• the virus can then infect the that cell

Question 25

why else is apoptotic mimicry good

Answer 25

suppresses inflammation and immune system response

Question 26

two infectious particles of vaccinia virus

Answer 26

MV and EEVs

- the virus presents two forms of these > forms 2 different immune responses

Question 27

features of MVs

Answer 27

single lipid bilayer

- very stable

Question 28

features of EEVs

Answer 28

like MVs but has extra 9 proteins

• have glycocylated proteins and glyco shielidng
• travel in blood stream

Question 29

what is F17

Answer 29

phosphoprotein
- major core component
DNA binding protein
-associated with lateral bodies