THE IMMUNE RESPONSES TO PARASITES

Unicellular parasites

Plasmodium – malaria

Giardia lamblia - giardiasis

THE IMMUNE RESPONSES TO PARASITES

Life cycle of Leishmania

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

THE IMMUNE RESPONSE TO THE SINGLE CELL PARAZITE LEISHMANIA

Dead parazitesIL-12

TNFIL-2

Th1

Th2

IL-2 IL-10

IL-4

IFNγ

Leishmania major

MACROPHAGE

NO, O2-,H2O2,OH-

CR3CR4

lipophosphoglycane

CLEARS THE INFECTION

DOES NOT CLEAR THE INFECTION

MACROPHAGE

Active radicals

ESCAPE MECHANISMS OF UNICELLULAR PARASITES

Variations in surface structure – gene conversionAlternating expression Trypanosoma

Lysis of phagosome mebraneComplement (DAF) like structures Trypanosoma cruzi

Inhibition of phagosome and lysosome fusion Toxoplasma

Poor antigenicity

Multicellular parasites

Helminths

Tape worm Diphyllobothrium latum9 m in length, lives in small intestineB12 deficiency (magaloblastic anaemia)

Trichinella spiralis „pork worm”

Life cycle of Schistosoma

Schistosoma mansoni Delayed Type Hypersensitivity - DTHFibrosis around the eggs in the liver Chronic inflammation – Fibrotic connective tissueInhibits the venous circulation of the liver

Granuloma in the liver

Hepatosplenomegaly

ECFNCF

C'

THE IMMUNE RESPONSE TO MULTICELLULAR WORMS

Can not be ingested by phagocytes

C3a, C5a Monocyte

Neutrophil

Eosinophil

Mast cellIL-3IL-4

Plasma cell IgE

mediators

B

B

Th2

Th2

IL-4, IL-5

LYMPH NODE

IgE IgG

BLOOD

Schistosoma mansoniActivated eosinophils bind to IgE-coated parasites via the low affinity FcεRII

and release their toxic contents onto the wormOther effector cells bind to IgG-coated parasites

Permeability

Schistosoma lárvát támadó eozinofil sejtek

Mast cells

Eozinophils

IgE – MEDIATED CELLULAR CYTOTOXICITY

Shistosoma

Eosinophil granulocyte

IgE

FcεRI

Death of worm

Granules

DEFENSE MECHANISMS AGAINST HELMINTHS

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

HOST ENVIRONMENT is accepted, resistant to complement and phagocytes

SIZE – no phagocytosis

RESISTANT – to reactive radicals and enzymes of macrophages and

neutrophils

Schistosoma mansoni Delayed Type Hypersensitivity - DTHFibrosis around the eggs in the liver Chronic inflammation – Fibrotic connective tissueInhibits the venous circulation of the liver