Leishmaniasis

Question 1

Some facts on Leishmania

Answer 1

• intracellular parasite
• (differentiation into) promastogote is transmitted by sandfly -> in phagolysosome of macrophage development into amastigote
• amastigotes multiply in macrophages

Question 2

Can you culture Leishmania in vitro?

Answer 2

Yes, promastigotes can be grown on biphasic blood agar at RT

Question 3

How to infect mice with Leishmania?

Answer 3

s.c. injection of promastigotes into footpad

Question 4

Describe the growth of Leishmania

Answer 4

• promastigotes grow and non-infectious
• start to become highly infectious when in stationary growth phase

dieselise development is dose-dependent

Question 5

Name a resistant and a susceptible mouse strain

Answer 5

C57BL/6 -> resistant

BALB/c -> susceptible

Question 6

What are the common sites for natural infection of Leishmania in rodents?

Answer 6

Ear and nose

Question 7

What is important in natural infection?

Answer 7

• inoculation of 100-1000 promastigotes (low dose)
• sandfly saliva exacerbates infection
  
  • maxadillan is a vasodilator
  • hyaluronidase degrades hyaluronan in ECM

Question 8

What models are there to study Leishmania infection?

Answer 8

artificial model
- s.c. inoculation into footpad (high dose)
- s.c. infection at ear (high dose or low dose)
- s.c. infection at ear with sandfly saliva (low dose)
- infection via the bite of infected sandflies
natural model

Question 9

How does Leishmania disseminate?

Answer 9

• popliteal lymph drains site of infection
• dissemination through whole body in BALB/c mice within 24h

Question 10

How to determine the parasitic load?

Answer 10

• limiting dilution assay
• real time PCR

Question 11

What is the reason for the polarised course of Leishmania infection in different mice models?

Answer 11

Th1/Th2 immune response

Th1 response can clear infection -> C57BL/6, CBA/J, C3H/HeJ
- CD4+ clones produce but IFN-γ & IL-12 but not IL-4
- activates the antimicrobial function of macrophages -> NOS2
Th2 response can‘t clear infection -> BALB/c
- CD4+ clones produce IL-4 & IL-10 but no IFN-γ

Question 12

Is Leishmania cleared when clinically cured?

Answer 12

No, still detectable Leishmania major in C57BL/6 mice 6 month after cure

reactivation possible when NOS2 is inhibited

Question 13

Name the first cells that migrate to site of Leishmania infection

Answer 13

Neutrophil granulocytes (>95% after 10h; 70% after 24h)
also the first to be infected