Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
What are the 3 different patterns of viral infections?
|
1. Acute - Influenza, rhinoviruses
2. Chronic - Hepititis, HIV 3. Latent/Relapsing - Herpes |
|
|
How do acute viruses ensure maximal viral protein production?
|
- Often shut off host cell protein production
Do this by: 1. Having Internal ribosome entry sites (IRES) that allow Viral DNA to bind ribosome directly 2. "Stealing" 5' cap from host cell mRNA's |
|
|
What effects are often observed in an acute viral infection?
|
Cytopathic effects - inclusions, synctia (cell fusion), cell swelling, cell death
|
|
|
What section of the immune system do acute viral infections deal with?
|
Innate Immunity
|
|
|
What does an acute viral infection trigger the production of?
|
Cytokines, interferon, and TNF
Note - INTERFERON is a hallmark of VIRAL infection |
|
|
What are 2 ways that acute viral infections combat the innate immune system?
|
1. Block INF/cytokine production
2. Inhibit apoptosis via FAS ligand, p53 activation |
|
|
What type of genome do chronic viral infections usually have?
|
DNA (or retrovirus that is RNA --> DNA, ex: HIV)
|
|
|
What are 3 ways that chronic infection causing viruses evade an evolving adaptive immune system?
|
1. Mutate and evolve
2. Produce proteins that modify the immune response -ex: some viruses encode proteins that down-regulate MHC I proteins 3. Establish a latent infection and wait for the immune response to subside |
|
|
What are 3 major routes of virus transmission?
|
1. Respiratory Tract - most common
2. Alimentary Tract 3. Urogenital Tract |
|
|
How do many viruses enter the body via the GI tract?
|
Enter through M CELLS which transport gut matter to peyers patches (transcytosis)
|
|
|
What are the 2 routes through which a virus can disseminate within the body?
|
1. Hematogenous spread through the bloodstream
2. Lymphatic Spread |
|
|
What is active dissemination?
|
When viruses attach to cells in order to migrate and disseminate throughout the body
Often on DENDRITIC CELLS |
|
|
How do viruses have the ability to move along the cell surface?
|
"cell surfing" - by surfing a virus can move to the base of cilia on an epithelial cell where it can be endocytosed
|
|
|
How do viruses such as Herpes, rabies, and polio move within a cell?
|
- On the host cells microtubules
- Often infect neurons and then migrate along axons in either direction - This allows virus to move great distances while being shielded from immune system |
|
|
What are 2 major ways that viruses can be spread cell to cell?
|
1. Makes host cell make contact/filopods that contact adjacent cells. Viruses bud at sites of cell to cell contact
2. Via actin "rockets" similiar to lysteria |
|
|
What are the 3 major ways that viruses cause disease?
|
1. Direct cytopathic effects - death of host cell by apoptosis
2. Virus induced immunopathology - cell mediated, anti-body mediated, autoimmunity, immunosuppression 3. Viral oncogenesis - cellular transformation by a virus. Ex. HPV |
|
|
What are the 2 important HPV gene products thats have been linked to tumorgenesis?
|
1. E6 - degradation of p53
2. E7 - binding and inactivation pRB |
