TITLE:
Proteoliposome and Polysaccharide-Based Meningococcal Vaccine Are Immunogenic in Infants and Toddlers and Primes for Memory against Serogroup C Polysaccharide
AUTHORS:
Oliver Pérez, Belkis Romeu, Judith del Campo, Caridad Zayas, Miriam Lastre
KEYWORDS:
Proteoliposome; Meningococcal Vaccine; Infants; Memory Response; Polysaccharide
JOURNAL NAME:
World Journal of Vaccines,
Vol.3 No.2,
May
22,
2013
ABSTRACT: Neisseria meningitidis capsular
polysaccharides are the main target of the protective immune response against
bacterial meningitis. They are thymus-independent type 2 (TI-2) antigens that
are poorly immunogenic and not protective in young children, and their
administration may impair subsequent challenge with the same polysaccharide.
These problems have been
addressed using three different vaccines consisting of 1) polysaccharide alone, 2) polysaccharide covalently conjugated to a carrier
protein, and 3) polysaccharide
with Proteoliposome (PL) adsorbed onto Al(OH)3. VA-MENGOC-BC? is one of the third types of vaccine. It contains PL (detergent-extracted
external membrane proteins forming
vesicles) and polysaccharide (Ps) from N.
meningitidis serogroups B and C (PsC), respectively. Nevertheless, there is a concern that to
overcome the TI-2 nature of Ps the covalently conjugation to a carrier is mandatory. Therefore, we evaluated the immune response
induced by VA-MENGOC-BC? in infants and toddlers in order to
determine whether it
stimulates the response against the PsC. High IgG anti PsC
and anti PL responses were seen following the administration of two doses in
infants and toddlers, after a 3rd dose in pre-teenagers, and after
confirmed carrier stages in young adults. The anti PL IgG response persisted longer
than anti PsC IgG response and IgM response against both antigens was
maintained. An IgG1 anti PL response predominated, as well as IgG4 > IgG3 > IgG1 anti
PsC responses. These results suggest that non-covalent incorporation of PsC
onto Al(OH)3 containingPL as adjuvant is immunogenic,
primes for memory, and induces long-lasting specific antibody response. The
improved PsC immunogenicity of this
vaccine may be due to the preferential and potent Th1 response induced in mice
and human by the PL as adjuvant.