1. THE IMMUNE RESPONSES TO PARASITES

2. THE IMMUNE RESPONSES TO PARASITES
Unicellular parasites
Plasmodium – malaria
Giardia lamblia - giardiasis

3. Life cycle of Leishmania

4. L. donovani – Visceral leishmaniasis (Kala azar)
L. tropica – Cutaneous leishmaniasis (Oriental sore)
L. brasiliensis - Mucocutaneous leishmaniasis (Espundia)

5. THE IMMUNE RESPONSE TO THE SINGLE CELL PARAZITE LEISHMANIA
Dead parazites
IL-12
NO, O2-,H2O2,OH-
IL-2
TNF
Active radicals
CLEARS THE INFECTION
Th1
MACROPHAGE
IFNγ
IL-2
IL-10
lipophosphoglycane
Leishmania major
CR4
CR3
IL-4
DOES NOT CLEAR THE INFECTION
Th2
MACROPHAGE

6. ESCAPE MECHANISMS OF UNICELLULAR PARASITES
Poor antigenicity
Variations in surface structure – gene conversion
Alternating expression Trypanosoma
Lysis of phagosome mebrane
Complement (DAF) like structures
Trypanosoma cruzi
Inhibition of phagosome and lysosome fusion
Toxoplasma

7. Multicellular parasites
Helminths
Tape worm Diphyllobothrium latum
9 m in length, lives in small intestine
B12 deficiency (magaloblastic anaemia)
Trichinella spiralis „pork worm”

9. Life cycle of Schistosoma
Schistosoma mansoni Delayed Type Hypersensitivity - DTH
Fibrosis around the eggs in the liver
Chronic inflammation – Fibrotic connective tissue
Inhibits the venous circulation of the liver

10. Granuloma in the liver

11. Hepatosplenomegaly

12. THE IMMUNE RESPONSE TO MULTICELLULAR WORMS
Can not be ingested by phagocytes
Plasma cell IgE
BLOOD
Mast cell
IL-3
IL-4
mediators
Th2
Permeability 
Eosinophil B B
IgE
IL-4, IL-5
Neutrophil
IgG
Th2
Monocyte
C3a, C5a
LYMPH NODE
Schistosoma mansoni
Activated eosinophils bind to IgE-coated parasites via the low affinity FcεRII and release their toxic contents onto the worm
Other effector cells bind to IgG-coated parasites

13. Schistosoma lárvát támadó eozinofil sejtek

14. Mast cells

15. Eozinophils

16. IgE – MEDIATED CELLULAR CYTOTOXICITY Eosinophil granulocyte
Death of worm
Shistosoma
IgE
FcεRI
Granules
Eosinophil granulocyte

17. DEFENSE MECHANISMS AGAINST HELMINTHS
HOST ENVIRONMENT is accepted, resistant to complement and phagocytes
SIZE – no phagocytosis
RESISTANT – to reactive radicals and enzymes of macrophages and
neutrophils
IgE – mediated protection
IgE-mediated antibody dependent cellular cytotoxicity ADCC
EFFECTOR CELLS: mast cells, basophils, and eosinophils
inflammatory mediators
vasodilation  recruitment of inflammatory cells  fluid outflow
smooth muscle cell contraction  mechanical removal
Schistosoma mansoni Delayed Type Hypersensitivity - DTH
Fibrosis around the eggs in the liver
Chronic inflammation – Fibrotic connective tissue
Inhibits the venous circulation of the liver