carrier protein, Prevnar 13 is able to generate a T cell-dependent
response to the CPSs, which are traditionally T cell-independent
antigens. This enables PCVs to generate a potent and long-lasting
immune response (demonstrated in part by IgM to IgG class
switching) in infant populations that serve as reservoirs for pneumococcal colonization.
Despite their utility, current vaccine formulations for pneumococcal disease face challenges due to the diversity of pneumococcal
CPSs (resulting in over 90+ unique S. pneumoniae strains or serotypes). Compounded by the difficulty of scaling the glycoconjugation process, which needs to be developed and performed
separately for each individual polysaccharide, broad coverage of
pneumococcal serotypes is limited due to the narrow subset within
current vaccine options (i.e., the 13 and 23 designations of Prevnar
and Pneumovax, respectively, represent the number of
S. pneumoniae CPS serotypes included in the vaccine products).
To overcome this limitation, we have developed a liposome-based
system for generating a glycoconjugate-like immune response to
pneumococcal polysaccharides that is more readily scalable regarding broader disease coverage.
To do so, we developed a liposome vaccine against
S. pneumoniae that provides a two-pronged protection strategy
against bacterial infection [5, 9]. In this strategy, we encapsulated
20+ pneumococcal capsular polysaccharides within a liposome that
was surface-decorated with pneumococcal protein antigens that are
upregulated in the biofilm-dispersed phenotype of the bacteria
[5, 9, 10]. Through the physical colocalization of the CPSs and
immunogenic protein antigens to the liposome, we were able to
achieve a glycoconjugate-like immune response against the CPSs,
without requiring direct covalent attachment [5, 9]. Consequently,
we demonstrated the ability to provide potent immunization (i.e., a
T cell-dependent immune response) against pneumococcal CPS
using a mechanism that is more amenable to expanding to additional serotypes than conventional conjugation chemistry.
Here, we describe our approach to formulating a liposomal
carrier that can harbor both S. pneumoniae polysaccharide content
and noncovalently colocalize surface proteins (such as CRM197).
Efforts to date have developed a process for encapsulating up to
24 pneumococcal capsular polysaccharides and attaching up to two
proteins to the liposome surface [5, 9]. The methods outlined
within this chapter illustrate the liposome encapsulation of polysaccharides (LEPS) featuring the pneumococcal 19F polysaccharide
and the surface-attachment of the green fluorescent protein (GFP,
as a surrogate protein useful in characterizing protein surface
attachment) using an Ni-NTA system.
478
Roozbeh Nayerhoda et al.
response to the CPSs, which are traditionally T cell-independent
antigens. This enables PCVs to generate a potent and long-lasting
immune response (demonstrated in part by IgM to IgG class
switching) in infant populations that serve as reservoirs for pneumococcal colonization.
Despite their utility, current vaccine formulations for pneumococcal disease face challenges due to the diversity of pneumococcal
CPSs (resulting in over 90+ unique S. pneumoniae strains or serotypes). Compounded by the difficulty of scaling the glycoconjugation process, which needs to be developed and performed
separately for each individual polysaccharide, broad coverage of
pneumococcal serotypes is limited due to the narrow subset within
current vaccine options (i.e., the 13 and 23 designations of Prevnar
and Pneumovax, respectively, represent the number of
S. pneumoniae CPS serotypes included in the vaccine products).
To overcome this limitation, we have developed a liposome-based
system for generating a glycoconjugate-like immune response to
pneumococcal polysaccharides that is more readily scalable regarding broader disease coverage.
To do so, we developed a liposome vaccine against
S. pneumoniae that provides a two-pronged protection strategy
against bacterial infection [5, 9]. In this strategy, we encapsulated
20+ pneumococcal capsular polysaccharides within a liposome that
was surface-decorated with pneumococcal protein antigens that are
upregulated in the biofilm-dispersed phenotype of the bacteria
[5, 9, 10]. Through the physical colocalization of the CPSs and
immunogenic protein antigens to the liposome, we were able to
achieve a glycoconjugate-like immune response against the CPSs,
without requiring direct covalent attachment [5, 9]. Consequently,
we demonstrated the ability to provide potent immunization (i.e., a
T cell-dependent immune response) against pneumococcal CPS
using a mechanism that is more amenable to expanding to additional serotypes than conventional conjugation chemistry.
Here, we describe our approach to formulating a liposomal
carrier that can harbor both S. pneumoniae polysaccharide content
and noncovalently colocalize surface proteins (such as CRM197).
Efforts to date have developed a process for encapsulating up to
24 pneumococcal capsular polysaccharides and attaching up to two
proteins to the liposome surface [5, 9]. The methods outlined
within this chapter illustrate the liposome encapsulation of polysaccharides (LEPS) featuring the pneumococcal 19F polysaccharide
and the surface-attachment of the green fluorescent protein (GFP,
as a surrogate protein useful in characterizing protein surface
attachment) using an Ni-NTA system.
478
Roozbeh Nayerhoda et al.