Transcript MALARIAL VACCINES

MALARIAL
VACCINES
IMMUNE RESPONSE TO
MALARIAL PARASITE
NAI(Non-adaptive immunity)protection against the clinical
disease
IMMUNE RESPONSE TO
MALARIAL PARASITE
IMMUNE RESPONSE TO
MALARIAL PARASITE
PfMEP1-expressed on infected
erythrocytic surface and mediates
binding of parasite to
receptors(CD36, chondoitin sulfate
A(CSA)
AGS WHICH ARE FAVORABLE
CANDIDATES FOR VACCINES
Accesibilty
Induce protective response (memory)
Lack/limited antigenic diversity
Eg:PfEMP1, Circumsporozoite Ag
Combine antigens from different stages
Combine several Antigens from a single
stage-Eg-MSP1
AGS WHICH ARE FAVORABLE
CANDIDATES FOR VACCINES
Type of immune response-TH/TC or
B-cell response
FACTORS AFFECTING
VACCINES
Parasite factors
drug resistance
increase in
multiplication rate
antigenic polymorphism
Host factors
immunity
cytokines
genetics( sickle cell
trait, MHC locus)
age ( no celebral
malaria in infants)
pregnancy
Geographic and social
factors
assess to treatment
political stability
cultural and economic
factors
trasmission intensity
VACCINE STRATEGIES
Anti-infection vaccines-
Irradiated sporozoites-usually used for
malaria naïve travellers
Drawbacks
not practical as delivered via a mosquito
bite
protection for a short period
no protection against erythrocytic
parasites
MUTANT Hb TAKES THE STING OUT
OF MALARIAL INFECTION
Thalassemia
HbC
Modification of Glucose-6phosphate dehydrogenase
Ovalocytosis
Duffy Ag–protects against P.vivax
infection
VACCINE STRATEGIES
Anti- morbidity/mortality vaccines
Designed against erythrocytic
parasites
Drawbacks
low immunity induced for a short
time
VACCINE STRATEGIES
Transmission blocking vaccines
Gametocyte –containing blood that
is used as the infection source for
the mosquito is mixed with serum
from animals immunized with human
antibodies
TYPES OF VACCINES IN
TRIAL
Synthetic peptide
vaccine
Recombinant vector
vaccine
Recombinant antigen
vaccine-RTS,S
vaccine
DNA vaccine- use of
gene gun
MUTANT Hb TAKES THE STING OUT
OF MALARIAL INFECTION
Sickle cell anaemia
seen mainly in Africa,India,
Mediterranaean, Middle East
1 in every 13 American blacks are
carriers
Mutant Hb-S instead of Hb-A
Rupture of infected RBC’s and
polymerisation of Hb makes it diffucult
for the parasite to digest