Viral Infection Flashcards
What is the first stage when a virus enters the host cells?
It replicates
What does the host cell release in the presence of a virus?
IFN-a
What is the role of IFN-a?
Causes the host cells to display parts of viral peptide on their surface MHC I molecules and prevents neighbouring cells from getting infected
When viruses kill infected cells, what happens to the viral particles?
They are released which activates dendritic cells to engulf them and transport them to local lymph nodes
What happens once the dendritic cells have transported the viral particles to the lymph nodes?
T cells enter, dendritic cells present viral peptides to naive T helper cells on their MHC II molecules which activates the T cells (Th1 and Th2)
What is the role of Th2?
Cause B cells to become plasma cells and produce antibodies
How are B cells activated?
Via co-stimulatory molecules and the release of cytokines
What is the role of Th1 cells?
Cause cytotoxic T cells to become activated by releasing cytokines
Which cells go towards the site of infection?
Activated T helper cells and cytotoxic T cells
How do cytotoxic T cells recognise which cells to kill?
MHC I molecules present viral peptides on the infected cell’s surface
How are natural killer cells activated?
By IFN-a, IL-2 and IFN-y
Where is IFN-a released from?
Infected cells
What are IL-2 and IFN-y released by?
Th1 cells
How does the body respond to viral proteins secreted from virally infected cells?
They can be neutralised or removed by antibodies binding to them. Bound antibodies may also guide natural killer cells to recognise infected cells and kill them
