Week 12 Flashcards
1
Q
Immune response to malaria
A
- human immune response can be divided
- sporozoite phase is initial and robust immune response but not usually helpful because they are only present for a short time
- immune response at liver stage (pre-erythrocytic)
- primary immune response is during blood stage (erythrocytic)
- also immune response at gamete phase
1
Q
Innate immunity
A
- Several known MAMPs (microbe associated molecular pattern)
- including hemezoin (drives inflammation), parasite DNA (recognized as foreign) and GPI anchors
- macrophages/monocytes, natural killer (NK) cells, and dendritic cells
2
Q
Cell mediated immunity
A
Proinflammatory response controls parasitaemia
3
Q
Humoral immunity
A
- Protective against disease
- Block RBC invasion,
- prevent cell adhesion
- opsonization: blocks ability to invade RBCs
4
Q
Induced immunity
A
- In endemic regions, adults are generally resistant to disease
- less symptomatic (not immune)
- Antibodies from these adults are effective treatments in others, even from different regions
- Suggests that induced immunity must be against epitopes that are conserved between diverse parasite populations
5
Q
Why are young children and adult travelers at increased risk for disease?
A
- don’t have the protective antibodies
- the antibodies develop through repeated exposure
6
Q
How does malaria avoid antibodies?
A
- Antigenic variation
- takes years of repeated exposure to develop natural resistance (eventually get an antibody that recognizes and unchanging aspect of the parasite)
7
Q
Immune modulation
A
- Malaria hides
- inside cells
- sequestered through adhesion to vessel walls in rosettes (uninfected RBCs attached to an infected RBC) - Antigenic variation
- mechanism not same as T.brucei
- Mutually exclusive expression, low switch rate - Negatively regulating dendritic cells following hemozoin uptake
- less antigen presentation - Some evidence for induced apoptosis of certain cell populations
