189
11.7.1 Glycoconjugate Vaccines Used for Prevention
from Biological Agents
As mentioned before in 1796, Edward Jenner discovered that the inoculation with
cowpox was able to protect against smallpox infection. Since then, different vaccines were developed to prevent infectious diseases [23, 24]. It was found that the
protection conferred by these vaccines was due to adaptive immunity (cellular and/
or humoral immunity) [23–26]. Unlike adaptive immunity, innate immunity does
not recognize every possible antigen. Instead, it is designed to recognize the microbial molecules that are essential for the survival of the pathogens. These unique
microbial molecules are called pathogen-associated molecular patterns (PAMPS)
[25, 26].
PAMPS include lipopolysaccharides (LPS, also called endotoxin) from the
gram-negative cell wall, peptidoglycan lipoteichoic acid from the gram-positive cell
wall, flagellin of bacterial flagella, the sugar mannose (a terminal sugar common in
bacterial, viral or fungal glycolipid and glycoprotein), bacterial or viral unmethylated CpG DNA, double-stranded and single-stranded RNA from viruses and glucans from fungal cell wall [25, 26].
Several pathogens and tumor cells exhibit unique glycan structures on their cellular membrane surfaces. For example, bacteria, microbes, and viruses all possess a
cell wall consisting of a plasma membrane and a capsule which were formed of
glycoproteins or complex polysaccharides [27].
These carbohydrate antigens can be used as targets for the development of carbohydrate vaccines. In the case of pathogenic bacteria, one has to distinguish Grampositive to Gram-negative bacteria that possess respectively, either capsular
polysaccharides (CPS) and/or lipopolysaccharides (LPS) that are implicated in all
virulence factors [28, 29]. The LPS are located on the outer membranes of Gramnegative bacterial cells. The study of the LPS revealed that it is composed of an
amphiphilic macromolecule, corresponding to an external core oligosaccharide
(O-specific chain, or hydrophilic antigen) and an internal core oligosaccharide
covalently linked to the lipid A [30]. Knowing that the oligosaccharide portion confers the immunological properties to the bacteria, different portions of the LPS have
been tested for vaccine development [31].
11.7.2 Lipopolysaccharide (LPS)
The lipopolysaccharides are located on the outer membranes of Gram-negative bacterial cells. Several studies on the isolation and structure and composition determination of LPS were reported [30, 32]. It was observed that LPS are composed an
external polysaccharide consisting of repeating of identical sugar oligosaccharide
units, called the O -specific chain, and an internal core oligosaccharide covalently
attached to a lipid A. The lipid A is a glycolipid composed by a β-D-(1 → 6) GlcN
11 Defense Against Biological Terrorism: Vaccines and Their Characterizations
11.7.1 Glycoconjugate Vaccines Used for Prevention
from Biological Agents
As mentioned before in 1796, Edward Jenner discovered that the inoculation with
cowpox was able to protect against smallpox infection. Since then, different vaccines were developed to prevent infectious diseases [23, 24]. It was found that the
protection conferred by these vaccines was due to adaptive immunity (cellular and/
or humoral immunity) [23–26]. Unlike adaptive immunity, innate immunity does
not recognize every possible antigen. Instead, it is designed to recognize the microbial molecules that are essential for the survival of the pathogens. These unique
microbial molecules are called pathogen-associated molecular patterns (PAMPS)
[25, 26].
PAMPS include lipopolysaccharides (LPS, also called endotoxin) from the
gram-negative cell wall, peptidoglycan lipoteichoic acid from the gram-positive cell
wall, flagellin of bacterial flagella, the sugar mannose (a terminal sugar common in
bacterial, viral or fungal glycolipid and glycoprotein), bacterial or viral unmethylated CpG DNA, double-stranded and single-stranded RNA from viruses and glucans from fungal cell wall [25, 26].
Several pathogens and tumor cells exhibit unique glycan structures on their cellular membrane surfaces. For example, bacteria, microbes, and viruses all possess a
cell wall consisting of a plasma membrane and a capsule which were formed of
glycoproteins or complex polysaccharides [27].
These carbohydrate antigens can be used as targets for the development of carbohydrate vaccines. In the case of pathogenic bacteria, one has to distinguish Grampositive to Gram-negative bacteria that possess respectively, either capsular
polysaccharides (CPS) and/or lipopolysaccharides (LPS) that are implicated in all
virulence factors [28, 29]. The LPS are located on the outer membranes of Gramnegative bacterial cells. The study of the LPS revealed that it is composed of an
amphiphilic macromolecule, corresponding to an external core oligosaccharide
(O-specific chain, or hydrophilic antigen) and an internal core oligosaccharide
covalently linked to the lipid A [30]. Knowing that the oligosaccharide portion confers the immunological properties to the bacteria, different portions of the LPS have
been tested for vaccine development [31].
11.7.2 Lipopolysaccharide (LPS)
The lipopolysaccharides are located on the outer membranes of Gram-negative bacterial cells. Several studies on the isolation and structure and composition determination of LPS were reported [30, 32]. It was observed that LPS are composed an
external polysaccharide consisting of repeating of identical sugar oligosaccharide
units, called the O -specific chain, and an internal core oligosaccharide covalently
attached to a lipid A. The lipid A is a glycolipid composed by a β-D-(1 → 6) GlcN
11 Defense Against Biological Terrorism: Vaccines and Their Characterizations