Malaria

Question 1

What merozoite organelles are important in pathogenesis?

Answer 1

Apical-prominent organelles:

• Microneme: gliding motility, invasion, adhesion.
• Rhoptries: invasion, adhesion, formation of the parasitophorous vacuole.

Question 2

What protein mediates endothelial binding in schizont-trophozoite stage RBCs? What receptors causes iRBC sequestration?

Answer 2

PfEMP1

This is encoded by the var gene family and contains variable numbers of 5 types of DBL domain, and 1-2 cysteine-rich CIDR domains. Numerous var genes appear in the parasite population.

Receptors:

• Var2CSA sequesters iRBC in the placenta
• ICAM-1 sequester iRBC in the brain
• CD36 sequesters to microvasculature