Biomaterials as Adjuvants
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drug targeting
Today:
Delivering activation signals to dendritic cells in vaccines
Reading:
Supplementary Reading:
ANNOUNCEMENTS:
Lecture 24 Spring 2006
1
Targeting vaccines to dendritic cells
Targets on DCs:
DEC-205
CD11c
TLR3
…particles, in general
Images removed due to copyright restrictions.
Please see: Kwon, et al. PNAS 102 (2005): 18264-18268.
Lecture 24 Spring 2006
2
Figure removed due to copyright restrictions.
Please see: Figure 4 in Kwon, et al. PNAS 102 (2005): 18264-18268.
Lecture 24 Spring 2006
3
‘REVERSE TARGETING’, CONTINUED
Lecture 24 Spring 2006
4
Targeting dendritic cells to
vaccines: ‘Reverse targeting’ to
mimic infection site recruitment
Infection site
2) Antigen
loading and
activation
1) Attraction to sites of infection
Infected cells
1) Chemotaxis:
Migration ‘up’ concentration
gradients of chemoattractantLecture 24 Spring 2006
3) Trafficking
to lymph
nodes
4) Activation of
naïve T cells in
the lymph nodes
5
PLGA
O
CH3
C
CH
CH
O
CH3
O
C
H2
C
C
O
C
x H2
O
O
C
y
O
O
‘Vaccination
site’ source well
~1 mm
1.2 mm
3 mm
collagen gel
Images removed due to copyright restrictions.
Please see: Zhao, X., et al. Biomaterials 26 (2005): 5048.
Lecture 24 Spring 2006
6
Dendritic cell attraction, antigen loading,
and activation
Alginate
microsphere
Antigen-delivery
nanoparticles
DCs
chemokine
Lecture 24 Spring 2006
7
How to encapsulate multiple
factors under mild conditions
for ‘reverse targeting’?
ALGINATE
COOH
H
COOH
O
O
H
OH
H
H
O
OH
H
OH
OH
H
H
H
COOH
OH
H
H
O
OH
COOH
OH
H
Mannuronic acid block
H
O
OH
H
H
H
O
O
H
O
H
H
H
H
Guluronic acid block
Figure by MIT OCW.
Image removed due to copyright restrictions.
Please see: http://www.lsbu.ac.uk/water/hyalg.html
alginate
CaCl2 solution
Wash
Iso-octane
Lecture 24 Spring 2006
8
Fluorescent nanoparticles
Fluorescent chemokine
100
% MIP-3α Released
80
60
40
20
0
0
1
Lecture 24 Spring 2006
2
3
4
Time (Days)
5
6
7
9
100
0
-200
-100
0
100
200
-100
y- distance from bead
y - d is ta n c e fro m b e a d
100
0
-200
-100
0
100
200
-100
-200
-200
x- distance from bead
x- distance from bead
25
Migration Histogram N=100
20
# Cells
15
10
5
Distance (μm)
Lecture 24 Spring 2006
10
42
5
37
5
32
5
27
5
22
5
17
5
12
5
75
0
25
collagen gel
200
200
Alginate microspheres loaded with:
# cells
Antigen nanoparticles
3.9%
Antigen nanoparticles
+ MIP-3α
17.9%
Amount of DQ-ovalbumin internalized
Lecture 24 Spring 2006
11
Issues in targeted delivery
•
Where is the target molecule expressed?
• Is it expressed by normal tissues?
• Is it stably expressed?
• Can select out evasive tumor cells/viruses
•
What is the affinity of binding?
•
immune response to targeting agent
Lecture 24 Spring 2006
12
ADJUVANTING VACCINES WITH
SYNTHETIC MATERIALS
MIMICKING PATHOGEN-HOST INTERACTIONS TO STIMULATE
IMMUNITY
Lecture 24 Spring 2006
13
ADJUVANTING FUNCTIONS OF BIOMATERIALS
• Sustain delivery of antigen
– Extracellular or intracellular
• Mimic pathogen delivery of activation
signals to dendritic cells and B cells
– Mimic multivalent surface structure of
pathogens
• Limit dose, but enhance response
Lecture 24 Spring 2006
14
SUSTAINING ANTIGEN DELIVERY TO DENDRITIC CELLS
EXTRACELLULAR DEPOTS
INTRACELLULAR DEPOTS
Images removed due to copyright restrictions.
Please see: Shen, et al. Immunology 117 (2005): 78-88.
Lecture 24 Spring 2006
15
pathogens as biomaterials: how the structure of pathogens relates
to immune responses
Image removed due to copyright restrictions.
Please see: http://www.kripafoundation.org/ Rehabilitation%20Programs/faqhiv.html
Image removed due to copyright restrictions.
Please see: http://textbookofbacteriology.net/BSRP.html
Lecture 24 Spring 2006
16
pathogens as biomaterials: how the structure of pathogens relates
to immune responses
Lecture 24 Spring 2006
17
Dose sparing of adjuvants by co-delivery in particles
Many immunostimulatory factors that activate
DCs are also potent inflammatory stimuli:
T cell proliferation measured ex vivo 10d after 2 injections:
Image removed due to copyright restrictions.
Please see: Heikenwalder, et al. Nat Med 10 (2004): 187-192.
Image removed due to copyright restrictions.
Please see: Diwan, et al. Current Drug Deliv 1, no. 4 (2004): 405-412.
Lecture 24 Spring 2006
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Nanoparticles that mimic pathogen
structural features
(1) Particulate
antigen delivery
-+
+
-+
+
+
+
+
-
-
-+
+
+
+
-
-
+
+
+
+
+
- -
+
+
-
-
+
+
- -
+
+
500 nm
(2) surface display
of repeated native
Ag epitopes
- -
CpG oligos
Poly(L-arginine)
Lecture 24 Spring 2006
(3) surface display
of ‘pathogen
associated
molecular patterns’
19
Image removed due to copyright restrictions.
Please see: Jain, S., et al. Biomacromolecules 6 (2005): 2590.
Lecture 24 Spring 2006
20
Images removed due to copyright restrictions.
Please see: Jain, S., et al. Biomacromolecules 6 (2005): 2590.
Lecture 24 Spring 2006
21
Proposed mechanism for antigen delivery to dendritic cells
Soluble Ova + CatD
1.
3.
2.
Graphs removed due to copyright restrictions.
Please see: Jain, S. et al. Biomacromolecules 6 (2005): 2590.
Lecture 24 Spring 2006
22
Cytokine Secretion by Activated DCs
18000
120
CpG
particles
particle-CpG
15000
IL-6 (pg/ml)
IL-12p70 (pg/ml)
160
80
soluble CpG
particles
particle-CpG
12000
9000
6000
40
3000
0
0.001
0.01
0.1
1
0
0.001
CpG concentration (PM)
Lecture 24 Spring 2006
0.01
0.1
CpG concentration (PM)
1
23
pathogens as biomaterials: how the structure of pathogens relates
to immune responses
Image removed due to copyright restrictions.
Please see: http://www.kripafoundation.org/ Rehabilitation%20Programs/faqhiv.html
Image removed due to copyright restrictions.
Please see: http://textbookofbacteriology.net/BSRP.html
Lecture 24 Spring 2006
24
B Cell Activation In Vivo
week 1
week 3
week 5
week 7
70000
Anti-ova IgG titers
60000
50000
40000
30000
20000
10000
0
ova
ova + CpG
particles
particles +
CpG
PpR60-CpG
ova + CFA
Samples
Lecture 24 Spring 2006
25
Synthetic pathogens?
Image removed due to copyright restrictions.
Please see: Troutier, et al. Langmuir 21 (2005): 1305-1313.
I
II
SAv
III
biotin-ova
biotinylated
phagocytosis
ligand
Lecture 24 Spring 2006
mobile ligand particles
26
Synthetic pathogens?
Figures removed due to copyright restrictions.
Please see: Figures 3 and 5 in Yu, et al. Adv Mater 17 (2005): 1477-1480.
Lecture 24 Spring 2006
27