Lecture 3 Flashcards
Viruses encode proteins that prevent host cell apoptosis. Why might that be beneficial for the virus?
It allows the virus to continue replicating in the cell, thus increasing the virus’ proliferation.
The following are some viral regulators of apoptosis:
Adenovirus gene: _____ which functions as a Bcl-2 homolog
Cowpox virus gene: ____A which inhibits caspases
HCMV gene: ___1+2 which inhibit TNF
HSV-1 gene: ____27 which stabilizes Bcl-2
E1B 19kDa
CrmA
IE1+2
ICP27
____ alpha and beta can be activated by viral infection in a cell, leading to activation of ISGs, TNF-alpha, and apoptosis. Viral infection can also lead to activation of ____-kapaB, which activates cytokine genes, leading to a local and systemic anti-viral response.
IFN-alpha and beta
NF-kapaB
Normally, NF-kapaB is localized in the _____, bound to ___kapaB. Upon infection, ___kapaB is phosphorylated, NF-kapaB is liberated and travels to the nucleus.
Cytoplasm
I-kapaB
I-kapaB
While IFN-alpha and beta are produced in most/all cells and are induced by ______, IFN-gamma is produced by ___-cells and ____ cells, and is induced by antigens, mitogens, IL-___and IL-___.
dsRNA
T-cells
NK cells
IL-2
IL-12
IFN acts through an extracellular receptor and induces the ____/____ intracellular pathway. ____ acts as a kinase and phosphorylates _____ which forms a dimer in the cytoplasm and translocates to the nucleus. The dimer binds one of two promoters (ISRE or GAS) of ____ genes.
JAK/STAT
JAK
STAT
ISG genes
IFN signaling can activate _____ (which can also be activated by ds-RNA), a protein kinase that phosphorylates ____-2a (an elongation factor) which inhibits translation.
PKR
eIF-2a
IFN can also activate ____(A) synthetase, which activates ____L, which cleaves dsRNA, blocking viral gene expression.
Oligo(A)synthetase
RNaseL
______ cells act by directly inhibiting viral infection via release of ______ and IFNs, or indirectly by triggering the _____ immune response via T-cell activation.
Dendritic cells
Cytokines
Adaptive
Mature dendritic cells have more processes and have up-regulated _____ class II which presents viral epitopes to T-cells.
MHC class II
Virally infected cells may down-regulate ____ class I molecules, which act as inhibitory signals for ____ cells. Without this signal, the ____ cells become active and kill the cell that’s activated them.
MHC class I
NK cells
NK cells
Live-attenuated virus vaccines can be made by growing viruses in non-______ conditions, for example by using non-human cell lines. The idea is that viruses, especially RNA viruses, undergo mutations, which can cause them to become avirulent.
non-Physiological conditions
Inactivated or killed virus vaccines are generated by “killing” the virus with chemical or physical procedures and then harvesting the ______ proteins to be used in the vaccine.
Envelope
_____ vaccines are created using only a subset of viral proteins. When using viral peptides, they are typically conjugated to proteins in order to elicit a better immune response.
Subunit
Viral vectors can also be used as vaccines. For example, _____ virus can be transformed with influenza _______ gene, which will cause host cells to produce the protein and allow the host to develop immunity to this protein. Initially, the gene is added to a plasmid that contains a _____ virus TK gene. Addition of the ______ gene into the TK gene disrupts the TK gene. This plasmid is transfected into host cells along with _____ virus. The viral DNA undergoes ________ recombination with the plasmid DNA, which confers the Vaccina virus with the influenza _______ gene. The recombined virus is selected for using _____, which kills virus that have the wild type TK gene (no recombination.)
Vaccina
Hemagglutinin
Vaccinia
Hemagglutinin
Vaccina
Homologous recombination
Hemagglutinin
BudR
