Edible Vaccines: eating our way to the eradication of disease.
-
Upload
melvin-ferguson -
Category
Documents
-
view
223 -
download
2
Transcript of Edible Vaccines: eating our way to the eradication of disease.
Vaccines
Eradication of small-pox Vaccine preventable diseases
– millions of deaths per year No vaccines
– HIV; ~2 million deaths per year
– malaria; 1.5 - 2.7 million deaths per year
There is a clear need for new vaccines, and vaccination strategies
Why is measles still killing children?
Failure to vaccinate:– fear
• safety and side effects
– misconceptions• prevalence and seriousness
– access/availability
Vaccine failure:– inactivation by heat– interference by maternal antibodies
A subunit based edible vaccine?
economical heat stable oral administration
– no more needles– mucosal immune response
sub-unit vaccine– unable to replicate– overcome maternal antibodies
Developing an edible vaccine for measles
Hemagglutinin (H) protein
• surface exposed protein
• targeted during the immune response
• sufficient to induce protective immunity
H F P
RNA + N L M
select an antigen
Tobacco expressing the MV-H protein
Western blot
50kDa
75kDa
100kDa
PNGase F - + - +
MV-H control
Transgenic tobacco
Feeding tobacco induces MV neutralising antibodies in mice
1
10
100
1000
0 49 78
days after initial feeding
MV
neu
tral
isat
ion
titre
MV-H control
Feeding tobacco may also induce a mucosal immune response
1
10
100
1000
10000
1 2 3 4 5 6 7 8 9
secr
eto
ry I
gA t
itre
MV-H Control Naive
titr
e
Treatment groups
Edible species
lettu
ce
toba
cco
con t
rol
MV-H75kDa
50kDa
From model system to practical vaccine
rice
con t
rol
Edible species – intraperitoneal experiment
From model system to practical vaccine
0
0.5
1
1.5
2
2.5
3
10 100 1,000 10,000
reciprocal serum dilution
abso
rban
ce (
655n
m)
MV-H tobacco
MV-H lettuce
control lettuce
MV-specific serum IgG titers
1
10
100
1000
10000
1 2 3 4 5 6 7
Edible species – intraperitoneal experiment
From model system to practical vaccine
MV-H lettuce control lettuce
MV-neutralisation titers
From model system to practical vaccine
an edible species delivery and dose issues
– quantity and number• higher antigen expression in plants
• targeting the antigen for better uptake
safety issues quality control and licensing GMO issues
Summary: tobacco, lettuce and rice can express the
MV-H protein
plant-derived MV-H protein is able to induce MV neutralising antibodies in mice
edible vaccines have the potential to address the limitations of the current measles vaccine