Lecture 3 part 1 Flashcards
Name the SIX viruses that can cause respiratory disease
influenza
parainfluenza
RSV (respiratory syncytial virus)
rhinovirus
coronavirus
adenovirus
of the 6 respiratory viruses, which have the longest incubation periods?
CORONA — 2-10 (mean of 5 days)
Adenovirus – 5-7 days
is the adenovirus a DNA or RNA virus? explain how you can remember this
DNA – has fairly long incubation period (5-7 days) because it needs to travel to the nucleus and can’t just replicate in the cytosol
rhinovirus causes what disease?
common cold
parainfluenza virus causes what disease?
laryngitis or croup
which virus causes bronchiolitis in mainly infants?
RSV
which virus causes SARS
severe acute respiratory syndrome (SARS)
caused by coronavirus
which virus causes pharyngitis and a febrile illness (fever)
adenovirus
WHERE does the flu undergo transcription and replication? from where is it assembled and released?
the flu is an RNA virus but almost behaves like a DNA one in that transcription and replication occurs in the NUCLEUS and not the cytoplasm
assembly and release occurs at the plasma membrane
explain the genome of an influenza virus
spiral
8 ssRNA(-) viruses – SEGMENTED GENOME
the genome of the influenza virus is segmented with 8ssRNA(-) viruses.
this structure causes what?
antigenic SHIFT – chance of reassortment of gene segments.
these MUTANT STRAINS cause epidemics and pandemcis
only influenza ____ and ___ are important for human disease.
which is the worst?
influenza A and B.
A is the worst
the influenza virus infects….
UPPER RESPIRATORY TRACT EPITHELIUM
explain how the influenza virus makes viral proteins in addition to genome for newly made viruses
recap: genome of influenza is 8 ssRNA(-).
makes PROTEIN—–
-RNA dependent RNA polymerase reads the (-) strand and converts it to a MESSAGE: ssRNA(+)
this mRNA is then translated into protein
makes GENOME—-
-RNA dependent RNA polymerase copies the (-) strand into a (+) strand (message.)
this serves as a TEMPLATE for generating more copies of (-) ssRNA
-the (+)ssRNA is then translated BACK to ssRNA(-) by RNA dependant RNA polymerase for the packaging of new virus
–this happens in the NUCLEUS. assembly and release at the PLASMA MEMBRANE
RNA dependent RNA polymerase is a VIRAL RNA polymerase associated with….
the nucleocapsid of the virus
name the influenza proteins that are associated with the RNA genome
PB2, PB1, PA —-> complex of 3 subunits to form RNA dependent RNA polymerase
NP – nucleocaspid protein
name influenza proteins that are produced in the host cell
HA
NA
M2
M1
NS1
NS2
HA is..
hemagglutinin – an attachment and fusion protein
NA is….
neuraminidase — aids in viral spreading. cleaves sialic acid in the mucus
M2 and M1 are…
proteins produced by influenza while in the host cell
M2 = membrane protein – a channel. facilitates the uncoating of viruses
M1 – matrix protein. a structural protein
NS1 and NS2 are…
proteins made by the influenza virus while in the host cell
NS1 – opposes the action of IFN (antagonist)
NS2 – nuclear export protein
differentiate between the host ranges of influenza A, B, and C
A – infects the most. humans swine, avians, mammals, bats, etc
B – humans and seals
C – humans, swines
differentiate between antigenic drift/shift capabilities of influenza A,B, and C
A — drift and shift
B – antigenic drift only
C – antigenic drift only
explain the envelope of the flu virus
pleomorphic envelope – varies in size and shape
paramyxoviruses cause which disease(s)?
measles, mumps, and RSV
explain the envelope, nucleocapsid, and genome of paramyxoviruses
envelope – pleomorphic with SPECIFIC attachment proteins
nucleocapsid – helical
genome – large, single strand ssRNA(-) viruses. LINEAR genome
paramyxoviruses invade cells through which mechanism?
membrane fusion
paramyxoviruses are released from host cells via..
budding
paramyxoviruses induce ___ formation
syncytia
how are paramyxoviruses transmitted?
where do they establish primary infection
by aerosols
primary infection site = respiratory tract
what are the 3 major genera of paramyxoviruses?
morbillivirus – measles (single serotype)
paramyxovirus – mumps (single serotype) and parainfluenza viruses 1-4
pneumovirus – RSV (respiratory synctial virus)
and metapneumovirus
paramyxoviruses have the same replication scheme as…
influenza
except replication and transcription does NOT occur in the nucleus – occurs in cytosol
when the newly made viruses bud off, they come together — syncytial formation
explain the pathway of measles
local replication in the respiratory tract – lymphatic spread – causes viremia.
then spreads rapidly to many places – urinary tract, CNS, lymphatic system, conjunctiva, respiratory tract, small blood vessels
the virus infected endothelial cells AND T immune cells produce a rash.
recovery yields LIFELONG IMMUNITY
what are 3 rare outcomes of measles
-postinfectious encephalitis (brain inflammation)
-no resolution of acute infection due to defected cell mediated immunity (CMI)
-SSPE (subacute sclerosing panencephalitis)
does the mumps virus produce a rash?
NO
explain the pathway of the mumps virus
local replication in the respiratory tract –> viremia (in bloodstream). causes a systemic infection
—goes to PANCREAS – can be associated with onset of juvenile diabetes
—-goes to PAROTID GLAND – virus multiples. causes swelling
-testes, ovaries, peripheral nerves, CNS, eye, innter ear
explain the properties of the envelope, capsid, and genome of adenoviruses
envelope – NO ENVELOPE
capsid – icosadeltahedral capsid
genome – linear dsDNA virus
how many serotypes of the adenovirus are there? which are the most common?
52 serotypes
1-7 are most common
explain the properties of the adenovirus in both permissive and non permissive cells
in permissive cells, the adneovirus is LYTIC
in non-permissive cells, the adenovirus is latent/persistant
where is the adenovirus REPLICATED and ASEEMBLED
in the nucleus
is the adenovirus transformative?
only in NON HUMAN CELLS
studying ______ virus is a useful tool in discovering gene replacement, anti-viral therapy, and cancer therapy
adenovirus
explain the replication scheme of the adenovirus
makes protein:
dsDNA virus is converted to (+) mRNA through DNA-dependent RNA polymerase of the host. this (+)mRNA is then translated into viral protein
makes genome:
-dsDNA in the genome is replicated into more dsDNA via a VIRAL DNA POLYMERASE called DNA-dependent DNA polymerase.
what is the name of the transactivator that increases the rate of gene exoression in adenoviruses
IE-E1A transactivator
early – increases proteins and replication
late – capsid genes
explain the VAPs of adenoviruses
the VAPs of adenoviruses are vibers at the vertices of the capsid. act as a HEMAGGLUTIN – bind to receptors on red blood cells to initiate viral attachment and infection. the VAPS are toxic to our cells, as well as the pentose base
on the adenovirus, attachment occurs via….
an immunoglobulin superfamily glycoprotein – coxsackie adenovirus complex (receptor)
which virus can bind MHC class 1?
adenovirus
what are the nucleocapsid associated proteins of paramyxoviruses?
NP(nucleoprotein) – binds and protects viral RNA
P (polymerase phosphoprotein) – facilitates RNA replication
L (RNA polymerase)
name the viral attachment proteins (VAPS) produced by paramyxoviruses IN THE HOST CELL
F protein
HN
H
G
M
What is F protein?
a viral attachment protein produced by paramyxoviruses in the host cell.
is is a membrane protein that promotes fusion and viral entry
paramyxovirus (singular) includes…
parainfluenza virus and the mumps
what is H? what virus possesses it?
a viral attachment protein that binds surface receptors.
present in morbilivirus (MEASLES)
hemagglutin
adenovirus has a protein that acts like this
is G a hemmagglutinin?
explain what it is
G is glycoprotein and it NOT a hemaglutinin
present in pneumovirus (RSV)
for attachment
what is M protein?
matrix protein – involved in assembly of virions
produced by paramyxoviruses
adenoviruses are internalized (brought into host cell) through what mechanism?
receptor mediated endocytosis
cant be membrane fusion – adenovirus has no envelope
how do adenoviruses get into the nucleus once they enter the host cell?
they lyse the vesicles they’re in and enter the nucleus (most likely through a pore)
name the adenovirus gene products (proteins)
E1A and E1B – INHIBIT P53 AND P105RB
E2 – viral DNA polymerase
E3 – immunosuppressant (blocks apoptosis and decreases MHC class I expression)
E4 – prevents apoptosis
VA RNAs (viral associated RNAs) – inhibit interferon repsonse
L1-L5 – structural/capside proteins
how is the adenovirus transmitted and spread?
transmission: inhalation, close contact, oral/fecal, fomites (objects that carry infection), poorly chlorinated pools
spread by VIREMIA (in the blood)
what is a definitive characterisitc (hallmark) of infection with adenovirus?
inclusion bodies (aggregate viral particles) without the cell being enlarged
name some clinical diseases that could be associated with the adenovirus
conjunctivitis (PINK EYE)
gastroenteritis
ARDS
laryngitis, bronchiolitis, pneumonia
acute pharyngitis, pharyngoconjunctival fever
