Transcript Carbohydrate Vaccines

Carbohydrate-based
Vaccines
Organic Chemistry 12 B
Instructor Dr. Adamczeski
Presented by Hanna Tong
5/3/06
8#
Abstract
Bacterial and viral infection is one of the major health problems worldwide.
Therefore, the development of new vaccines to combat these types of infections
is very important. Vaccines have generally been made from weakened or killed
pathogens, or from several variable carbohydrate molecules, which are extracted
from the cell-surface of bacteria and viruses. The carbohydrate-based agents
from natural sources can be difficult to isolate, and the natural isolates can have
heterogeneity and contamination problems. An alternative would be to identify
antigenic carbohydrates and then synthesize them in the laboratory.
This seminar will introduce the general outlook of synthetic carbohydrate-based
vaccines, the history of development of them, and their application. Some
applications include the first approved human vaccine based on a synthetic
carbohydrate Quimi-Hib, cancer-specific carbohydrate vaccines: the Globo-H,
and multiantigenic vaccine. I will also discuss some common pharmaceutical
techniques used to synthesize them, including: OPopS, and Automated Solid
Phase Synthetic Technology, theirs developers, and principles.
Outline
I.
II.
III.
IV.
V.
VI.
VII.
Introduction
1.
What is Vaccines?
2.
What is Antibody?
2.
What is Carbohydrate?
3.
Classic Carbohydrate Vaccines
4.
Synthetic Carbohydrate Vaccines
Why Carbohydrate?
History of Development of Carbohydrate Vaccines
Synthetic carbohydrate: Advantages (comparing with carbohydrates
from natural sources)
Synthesis: recently developed carbohydrate synthesis techniques
1.
Basic Synthesis Technique
2.
OPopS (Optimer One-Pot Synthesis)
3.
Automated Solid-phase Synthetic Technology
Applications: some carbohydrate-based vaccines:
1.
The first approved human vaccine based on a synthetic
carbohydrate: Quimi-Hib
2.
Cancer: Globo H, multiantigenic agent
Conclusion
What is …
Vaccine, Antibody, Carbohydrate,
& Carbohydrate Vaccine ?




Vaccine: a preparation of a weakened or killed pathogen such as a bacterium
or virus, or of a portion of the pathogen's structure that upon administration
stimulates antibody immunity against the pathogen but is incapable of
causing severe infection.
Antibody: protein made by certain white blood cells in response to a foreign
substance (antigen).
Carbohydrate: are sugars or several sugars linked together, contains only C,
H, and O, usually in the ratio 1:2:1.
Carbohydrate Formula: (C)n+(H2O)n = carbon + water = carbohydrates.
Classic carbohydrate-based vaccine: carbohydrate used in the vaccine is
isolated from natural sources, hence can have heterogeneity and
contamination problems.
Alternative: identify carbohydrates and then synthesize them in the
laboratory.
Why Carbohydrate ?

Cells of our body have sensors
made out of carbohydrates (on
outer surface of plasma
membrane)

These sensors can detect
many kinds of stimuli, and can
signal the immune system to
respond.
Specific carbohydrates that
carry appropriate recognition
properties are synthesized and
used in carbohydrate vaccines.
http://wong.scripps.edu/
History of Development
In the ‘20s and ‘30s, K. Landsteiner, O. Avery, and W. Goebel (Rockefeller
University) showed that nonimmunogenic carbohydrates from bacteria could be
converted into immunogenic (produced protective immune responses) by attaching
them to proteins and inducing antibodies.
Around 1980, two research teams of the University of Rochester and of
National Institute of Child Health & Human Development (NICHD),
Bethesda, Md, working independently, developed a semisynthetic
(natural source carbohydrate combined with carrier protein)
carbohydrate Hib vaccines.
Also around 1980, researcher H. Jennings (National Research
Council of Canada's Institute of Biological Sciences, Ottawa),
and coworkers, developed a semisynthetic carbohydrate
vaccine that protects infants against bacterial meningitis, the
most common form of meningitis in young children.
The first commercial vaccine made from a synthetic
carbohydrate was approved Nov. 2004 in Cuba.
Borman, Stu. Carbohydrate Vaccines. Chemical & Engineering News, August 9, 2004,
Volume 82, Number 32, pp. 31-35
Synthetic Carbohydrate Advantages

Natural carbohydrates and glycopeptides are too scarce and too difficult to
isolate.

Synthetic carbohydrates can be produced as homogeneous single
compounds, while naturally derived carbohydrates are heterogeneous
mixtures and may include impurities and contaminants.

Medicinal chemistry techniques can be used to derivatize and modify
synthetic carbohydrates to make vaccines that are more immunogenic than
those based on natural carbohydrates.

Synthetic carbohydrates can have very precise construct, and the variables of
chain length and chain density can be controlled because product is pure.
The advent of synthetic carbohydrate vaccines
is a triumph of tremendous advances in
oligosaccharide synthesis, since …
"Without the years people have put into
synthetic organic chemistry and carbohydrate
chemistry, you wouldn't be able to make the
kinds of investigational vaccines you can today.“
Chem. Prof. Samuel J. Danishefsky (Memorial Sloan-Kettering Cancer Center (MSKCC) & Columbia University, N.Y City)
Basic Synthesis Technique
sugar1- OH + HO - sugar2
sugar1- + - O - sugar2 + -OH + H-
sugar1- O - sugar2 + HOH
http://www.bergen.org/ACADEMY/Bio/molbio/LACTOSE_SYNTH/LactoseSynth.html



Condensation reaction.
-OH from the first and H- from the
second sugar are removed.
Glycosidic bond (-O- bond connect.
the two sugars) is formed.
http://www.bergen.org/ACADEMY/Bio/molbio/LACTOSE_SYNTH/LactoseSynth.html
Synthesis two beta-glucoses
Carbohydrate Synthesis Technique:
1. OPopS
Optimer One-Pot Synthesis.
 Developed by Dr. Chi-Huey Wong, Prof.
of Chemistry, The Skaggs Institute for
Chemical Biology & workers.
 Principle:
- Put all the chemicals in the pot.
- Let them put themselves together, the
most reactive chemical assembles first .

Main Aspects:
1. Synthesize a number of mono- &
disaccharides w/different protecting group
patterns & measure their reactivity.
2. A computer program calculates the
reactivity of involved reactants & selects
presynthesized building blocks.

Prof. Chi-Huey Wong
http://wong.scripps.edu/boss.htm
3. Computer program analyzes target
oligosaccharide and suggests a set of
presynthesized carbohydrate blocks,
combines them from most to least
reactive
get desired product in one
reaction.
http://www.scripps.edu/chem/wong/optimer.html
Carbohydrate Synthesis Technique:
2. Automated Solid-phase Synthesis

Developed by Dr. Seeberger, Prof. for Organic Chemistry
Zurich, Switzerland), & coworkers.


Inspired by Merrifield's solid-phase peptide synthesis.
This method is applied to produce vaccine candidates
for malaria, HIV, tuberculosis, & bacterial infection).

Principle:
(ETH
- Attach one side of the sugar to a secure support, the
chain grows at the other side.
- Add monosaccharide one by one.
- After everything is done, cleavage from the solid support

Main Aspects:
Prof. Peter. H. Seeberger
http://www.seeberger.ethz.ch/people/seeberger
1. Select ‘solid phase’, a polymer inert to all reaction conditions. Most solid-phase is
polystyrene, cross-linked with 1% divinylbenzene.
2. Select linker to attach 1st sugar to the solid support, which inert to all reaction conditions.
3. Select glycosylating agents: such as thioglycosides, anomeric fluorides, trichloroacetimidates, and sulfoxides.
4. Select protecting group: permanent protection for unoperated hydroxyl, temporary one for
involved hydroxyl.
5. Repeat the coupling cycles to get the desired sequence.
6. Remove unreacted reagents at any synthetic step by a wash procedure.
http://pubs.acs.org/cgi-bin/jtextd?chreay/100/12/html/cr9903104.html#tcrx56
Automated Solid-phase Synthesis: Strategies
Donor-bound: Dimethyldioxirane (DMDO) converts
the double bond into epoxide. OH of acceptor 52
reacts w/ 51 to give the desired -glycoside 53.
Repeat this procedure to get (1 6)-linked
tetrasaccharide 55.
http://pubs.acs.org/journals/chreay/100/i12/figures/cr9903104h00011.html
Acceptor-bound: Excess of donor is needed
to maximize yield.
http://pubs.acs.org/journals/chreay/100/i12/figures/cr9903104h00013.html
Bidirectional: oligosaccharide grows in both directions.
Used to prepare branched structures.
.
http://pubs.acs.org/journals/chreay/100/i12/figures/cr9903104h00012.html
Applications of synthetic
carbohydrate vaccine
"synthetic vaccines against any unique disease-associated carbohydrate structures should be possible"
(Prof. Seeberger)
Under study: a
vaccine candidate for
candidiasis, a type of
fungal infection that can
affect the skin, mucous
membranes, or
bloodstream.
http://pubs.acs.org/cen/coverstory/8232/8232vacci
nes.html




Cuba-approved vaccine Quimi Hib against Haemophilus influenzae type b.
Globo H: breast cancer vaccine candidate.
Unimolecular multivalent vaccine candidate: vaccine with 5 different cancer
antigens.
Many kinds of vaccine for fungal, bacterial, and protozoan infections etc. have
been developed, is developing, or are currently tested in animals.
Borman, Stu. Carbohydrate Vaccines. Chemical & Engineering News, August 9, 2004, Volume 82, Number 32, pp. 31-35
Quimi Hib - The first approved human
vaccine based on a synthetic carbohydrate





Prevents Haemophilus influenzae
type b (Hib), that causes
pneumonia & meningitis in
infants and young children.
Developed by Cuban and
Canadian researchers
Passed 7 clinical trials. The
efficacy in long-term protection
in newborns was almost 100%.
Total immunized population >
2 000 children.
The carbohydrate component is
sPRP (poly-ribosylribitol
phosphate oligosaccharide),
contains 7 units of Haemophilus
influenzae type b polysaccharide.
Applied but simplified existing
synthesis process for 5 units to
get 7 units rPPR.
http://pubs.acs.org/cen/coverstory/8232/8232vaccines.html
sPPR conjugated to a tetanus toxoid (TT)
protein.
 sPRP-TT mixed with aluminium phosphate
(immune activator, stimulates PRP-specific
antibodies) using a process devised by
reseachers of University of Dundee, Scotland.
Globo H Cancer Vaccine
(OPopS application)

Cancer carbohydrate vaccines evoke
antibodies against the carbohydrate
antigens of cancer cells , that aren't
produced by normal cells.

Globo H is a carbohydrate which acts
as antigen on breast cancer, is
synthesized by Optimer Pharm.

In Globo H, 4 monosaccharides are
linked with 1 disaccharide to make
Globo H hexasaccharide. This is then
linked to a protein carrier to make a
candidate breast cancer vaccine. (Ac
= acetyl, Bn = benzyl, Bz = benzoyl,
Lev = levulinoyl, STol = thiotoluyl,
Troc = 2,2,2-trichloroethoxycarbonyl).

A Phase I clinical trial of this Globo Hprotein conjugate & an immune
activator was recently carried out.
http://pubs.acs.org/cen/coverstory/8232/8232vaccines.html
Multiantigenic agent:
Cancer-specific Carbohydrate Vaccine
http://pubs.acs.org/cen/coverstory/82
32/8232vaccines.html
Includes a single glycopeptide that contains five tumor antigens (Globo H, STn, Tn,
Lewis, and TF are tumor antigens; Ac = acetyl). A linker is attached to the
glycopeptide, followed by a deprotection and subsequent conjugation to two different
immunogenic carriers, keyhole limpet hemocyanin and N- -palmitoyl-S-[2,3bis(palmitoyloxy)-(2RS)-propyl]-L-cysteine, resulted in the vaccine construct.


Is considered as next generation synthetic carbohydrate vaccine.
References









Borman, Stu. Cancer Vaccine is Best in Class. Chemical & Engineering News,
Volume 83, Number 37, p. 10 (9/2005)
Borman, Stu. Carbohydrate Advances. Chemical & Engineering News, Volume
83, Number 32, pp. 41-50 (8/2005)
Borman, Stu. Carbohydrate Vaccines. Chemical & Engineering News, Volume
82, Number 32, pp. 31-35 (8/2004)
Borman, Stu. Combinatorial Chemistry. Chemical & Engineering News, Volume
80, Number 45, pp. 43-57 (11/2002)
France, Simon. Vaccine Sweetness Synthesize. Drug [email protected]
http://www.nature.com/drugdisc/res_high/articles/nrd1507.html
OPopS Technology. http://www.optimerpharma.com/core_technology.htm
Professor Chi-Huey Wong. http://wong.scripps.edu/
Seeberger Research Group. http://www.seeberger.ethz.ch/
Seeberger, Peter H. & Haase, W. Christian. Solid-Phase Oligosaccharide
Synthesis and Combinatorial Carbohydrate Libraries. ACS
http://pubs.acs.org/cgi-in/jtextd?chreay/100/12/html/cr9903104.html#tcrx3