molecular interactions involved in erythrocyte invasion by malaria parasite thesis submitted to...
TRANSCRIPT
Molecular Interactions Involved In Erythrocyte Invasion By
Malaria Parasite
Thesis Submitted to
Jawaharlal Nehru University
for the Award of the Degree of
Doctor of Philosophy in Molecular Genetics
by
International Centre for Genetic Engineering and Biotechnology
RICCARDO S. GATTA
Introduction
Malaria parasite biology and life cycle,
Expression of binding domain of P.vivax Duffy-binding protein,
Morphology of erythrocyte invasion by Plasmodium spp.,
Malaria parasite - host interactions,
Recombinant PvRII produced as secreted protein in insect cells,
Mouse anti-PvRII antibodies block erythrocyte binding…
Overview:
Work In Brief:
- functionally active,- immunogenic,
{after Sherman, 1998}
Indian medical texts1600 BCE
Hippocrates Lucretius 400 BCE 95BCE
Quinine c 1640 CE
Giovanni Maria Lancisi 1716
Charles Louis Alfonse Laveran 1880
Ronald Ross 1897
Malaria TIMELINE- Introduction
Identification
Chloroquine1934
DDT 1937
WW I I1939-1945
WHO - ERADICATION 1956
DDT resistance 1960’s
WHO - CONTROL 1967
{after Sherman, 1998}
IntroductionMalaria TIMELINE- Control
Artemisinins1979
Gene cloning 1983
Genome sequencing 2002
- Search for new drugs- Vaccine development
{after Sherman, 1998}
IntroductionMalaria TIMELINE- Major Advances
{after WHO, 2000}{after WHO, 2000}
Population at risk40% world-wide
~ 2 billion people
Population infected ~ 200 million people~ 150 million more each year
Research focus ...new drugs ...vaccines
Fatalities ~ 2 million each year~ 3000 children under five die each day
Malaria: a world-wide burden Introduction
{From Hoffman, 1996}
Parasite Life Cycle – Blood StageMalaria
{after Chitnis and Miller, 1994 and Miller and Hoffman, 1998}
The target is:
Vaccines aim to:
1. Sporogonic or Mosquito Stage,2. Exo-erythrocytic or Liver Stage,3. Erythrocytic Stage.
- Vaccine-induced host antibodies (Abs) are taken up with the blood meal, - Block sporozoite development, - Target vector directly, - Abs to sporozoites, - Cellular response: induce both cytotoxic
T-cells and IFN-γ, - Reduce symptoms, - Abs that block merozoite cytoadherance and/or invasion of RBCs, - Abs to antigens on parasitized RBC, - Induce IFN-γ and other cytokines would destroy infected RBCs,
Transmission
BlockingPrevent Infection
and Disease
Reduce Parasitemia
and Disease Invasion – Targets
Malaria Vaccines
MSP family, MAEBL and extended family, AMA-1, and SERA
{From Bannister et al., 2000}
Rhop / RAP complexesDBL-EBP family / PvRBPsSurface molecules Apical organelle localizationBlood Stage – MerozoiteMalaria Parasite
{Caramello, 2002}
Morphology – FiguresMalaria Parasite
Pf
Pv
{Caramello, 2002}{WHO, 1998}
Morphology – ImagesMalaria Parasite
1: Attachment – Reorientation
-PvRBPs,
-MSP-1 complex,
-AMA-1,
-MAEBL...
{From Cowman and Crabb, 2002, and Chitnis and Blackman, 2000}
MorphologyErythrocyte Invasion
2: Irreversible attachment and
junction formation
- micronemes
- rhoptries...
{From Cowman and Crabb, 2002, and Chitnis and Blackman, 2000}{From Cowman and Crabb, 2002, and Chitnis and Blackman, 2000}
{From Dvorak et al., 1975}
3: Parasitophorous vacuole and invasion
MorphologyErythrocyte Invasion
Plasmodium spp. have individual invasion specificities
Erythrocytes / treatment
P.vivax P.knowlesi P. falciparum
Human Duffy +ve + + +
Human Duffy –ve.
Human Neuram.
Rhesus
Rhesus Chymo.
- - +
ND + ND- + -+ + -
Erythrocyte ReceptorsErythrocyte Invasion
Two DBL domains: P. falciparum EBA-175, EBL1, BAEBL, JESEBL, PEBL...
I II III IV V VI
TMSS CYT RII
Single DBL domain:
P. vivax DBP, P. knowlesi DBP (α, β, and γ proteins)…
{after Chitnis and Miller, 1994}
I II III IV V VI
TMSS CYTFIIFI
Erythrocyte Binding ProteinsErythrocyte Invasion
Erythrocyte receptors
{From Tournmouille, 1997}
- ligands can acts as immunogens to induce invasion blocking Abs.
- find parasite ligands,
Parasite Ligands
(Region II)
Erythrocyte Receptors
P. vivax RII ONLY Human Duffy antigenP. knowlesi α-RII Rhesus / human Duffy Ag
P. falciparum F2 Sialic acid / glycophorin A
Sialic acid (rhesus RBC)β-RII
Rhesus RBC (unknown) γ-RII
External
Internal
Duffy Antigen Receptor for Chemokines
(DARC)
Receptor – Ligand InteractionsErythrocyte Invasion
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forPART2