Viral and fungal infections Flashcards
What cells are responsible for killing virally infected cells early in infection?
NK
How are Nk activated?
IFN alpha and gamma release
What do NK release?
IFN gamma - type II interferon
Function of IFN gamma
Activate macrophages and lead to T cell activation
How are Cd8 Tc cells activated from naive cells?
Recognition via MHC class I, co-stimulation, IL-2 release (proliferation), cytokines
How are effector Tc cells activated?
Recognise virally infected cells via TCR/MHC class I - no second signal required
How do Tc cells cause death
Release cytotoxins that promote apoptosis (and IFN gamma to promote presentation)
What causes AIDS?
HIV1/2 causing decreased CD4 T cells
How does HIV enter cells
a) initially
b) late stage
a) CCR5 co-receptor on DC and macrophages
b) CD4 receptors
After initial infection of HIV it causes flu-like symptoms until when?
CD8 Tc and anti-his specific antibodies control the infection (seroconversion)
After seroconversion the no. of Cd4 cells increases and controls the infection but then decreases again why?
High mutation rate of hIV means it can escape the immune response
When does HIV infection become AIDS?
When rate of decline of Cd4 overtakes rate of replacement
What is AIDS?
Acquired immunodeficiency syndrome
What are fungal infections associated with?
Immunodeficiency
Most common fungal infection fo mouth?
Candida albicans
