What are the 2 main concepts for viral entry?
- Recognition of host receptor (attachment)
- Mechanism to release genome (for eg. in the cytoplasm)
can viruses be passively transported?
no too large
how does Viruses find the “right” receptor?
Random electrostatic interactions do occur but will not initiate infectious cycle bc receptor is specific
what is a coreceptor? which type of virus usually uses this?
In some cases, a second receptor is very essential for viral entry (never for viruses that infect plants and yeast, usually for humans)
why do cells have these receptors?
- transmembrane surface membrane proteins receptors are used for host cells not just for virus and can be many viruses’ entry points
what is the HIV-1 receptor?
CD4 and Chemokine receptors (CC and CXC)
What is the poliovirus receptor?
PVR
What is the Coxsackie B receptors?
PVR and CAR
What is the adenovirus 2 and 5?
CAR + Integren
What is the Murine Leukemia virus receptor>
Cationic amino acid transporter
What is th human coronavirus receptor ?
amino-peptidase N
What is the measles virus receptor>?
CD46
what is the rhinovirus receptor?
LDL-receptor
what is the SARS-CoV2 entry receptor? what did the mutation of omricron cause?
angiotensin-converting enzyme 2 receptor (ACE2) – in humans usually cardiovascular function found in respiratory tract in lungs
- at first the receptor was better in lower resp tract - lungs (follow incubation longer)
- omnicron was receptors in nose (easier transmission)
What are the Two different modes of attachment? what do they depend on?
depdends on outer shell of virus
non enveloped hard shell
enveloped virus (lipid layer + glycoprotein)
What are the details of poliovirus?
family, genome type, symmetry, envelope
- family: picornaviridae
- ss + RNA
- 3 viral protiens (1,2,3)
- icosahedral
- non-enveloped virus
- naked virion
what is a naked virion?
Viruses can “release” their genomes at the plasma membrane
how does polivirus entry the host cell?
- VP1 interacts with receptor PVR making conformational change
- makes pore on host cell surface
- polivirous injects RNA directly across membrane
what is an example of an envelope virus? what is its glycoprotein? what does the glycoprotein interact with on host?
influenza virus
- has hemagglutinin viral envelop glycoprotein that binds to cell host receptor (sugar sialic acid)
what are the types of sialic acid? What do each type mean?
2-6 linkage btwn sialic acid and galactose preferred by human influenza virus
2-3 linkage preferred by avian influenza virus
where are the 2 types of sialic acid receptors found?
Sialic acid receptors with 2-6 linkages in upper and lower tract. Will bind human influenza viruses
Sialic acid receptors with 2-3 linkages in lower tract.
Will bind avian influenza viruses
can humans be infected with avian influenza virus?
Very deep breath of many virions; but possible
What are the 3 ways of virus endocytosis? what type of transport?
- phagocytosis (solid particle intake in a phagosome)
- pinocytosis (extracellular fluid in vesicle)
- receptor mediated endocytosis (receptor attaches to virus and have coated vescicle from coated pit on inner layer of cell)
ACTIVE TRANSPORT
what is a trigger for viral genome release?
pH difference in cell
