Vector-Host-Parasite immune interactions Flashcards
What are the main host immune responses to ticks?
APCs pick up tick immunogens in draining lymph.
Basophils, eosinophils and T cells go to bite site.
Antibodies bind basophils producing histamine.
How does tick saliva modulate the host immune response?
Inflammation inhibitors bind to histamine.
Cytokine modulation by changing Th1 to Th2 cells as Th1 are more protective -so down-regulated.
Anti-coagulation, vasodilation and binding wound healing growth factors.
Why is the midgut a good target for the anti-tick vaccine?
It doesn’t show variability and reduces tick attachment, fecundity and egg production.
How do African trypanosomes affect the tsetse fly ability to efficiently feed?
Tsetse can no longer inhibit haemostatic reactions as the parasite down regulates salivary gland gene transcription which reduces platelet aggregation and anti-coagulate activity making feeding more difficult and therefore improving chances of transmission.
How does the salivary gland peptide, erythema help the sandfly to feed?
It is a vasodilator.
How does leishmania affect the sandflies biting and feeding behaviour?
It increases the sandfly biting persistence, and feeding on multiple hosts by producing a gel plug with PSG.
PSG recruits macrophages and increases synthesis of polyamines for intracellular parasite growth.
How do mosquito salivary proteins in Aedes aegypti affect dengue transmission?
MSPs disrupt haemostatic and immune responses to facilitate efficient blood feeding.
How saliva effect malaria infection?
Increases sporozoite infectivity, and repeated prior exposure to saliva reduces infectivity in host.
How does parasite presence affect vector feeding?
Parasite decrease mosquito feeding during pre-infectious stage but increase during infectious stage.
Sporozoites increase likelihood of mosquito taking multiple blood feeds.
May change the time of the night that the mosquito feeds?
