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E u r o S c i C o n C o n f e r e n c e o n
PEDIATRICS
2017
Pediatrics 2017
Volume:3 Issue:4(Suppl)
Journal of Pediatric Care
ISSN 2471-805X
N o v e m b e r 1 3 - 1 4 , 2 0 1 7
L o n d o n , U K
Page 42
First
characterization
of immunogenic
conjugates of Vi
negative Salmonella
Typhi O-specific
polysaccharides
with rEPA protein for
vaccine development
M Salman
1, 2, 4
, F St. Michael
1
,
A Ali
2
, A Jabbar
5
, C Cairns
1
,
A C Hayes
1
, M Rahman
2
, M
Iqbal
2
, A Haque
3
and
A D Cox
1
1
Human Health Therapeutics Portfolio
National Research Council, Canada
2
National Institute for Biotechnology
Faisalabad, Pakistan
3
University of Faisalabad, Pakistan
4
Abasyn University, Pakistan
5
Mirpur University of Science & Technology
Pakistan
J Pediatr Care 2017, 3:4(Suppl)
DOI: 10.21767/2471-805X-C1-003
E
fficacious typhoid vaccines for young children will
significantly reduce the disease burden in developing world.
The Vi polysaccharide based conjugate vaccines (Vi-rEPA)
against
Salmonella
Typhi Vi positive strains has shown high
efficacybutmaybeineffectiveagainstVinegativeS.Typhi.Inthis
study, for the first time, we report the synthesis and evaluation
of polysaccharide-protein conjugates of Vi negative S. Typhi as
potential vaccine candidates. Four different conjugates were
synthesized using recombinant exoprotein A of
Pseudomonas
aeruginosa
(rEPA) and human serum albumin (HSA) as the
carrier proteins, using either direct reductive amination or an
intermediate linker molecule, adipic acid dihydrazide (ADH).
Upon injection into mice, a significantly higher antibody titer
was observed in mice administrated with conjugate-1 (OSP-
HSA) (P=0.0001) and conjugate 2 (OSP-rEPA) (P≤0.0001) as
compared to OSP alone. In contrast, the antibody titer elicited
by conjugate 3 (OSPADH-HSA) and conjugate 4 (OSPADH-rEPA)
were insignificant (P=0.1684 and P=0.3794, respectively). We
conclude that reductive amination is the superior method to
prepare the S. Typhi OSP glycoconjugate. Moreover, rEPA was
a better carrier protein than HSA. Thus OSP-rEPA conjugate
seems to be efficacious typhoid vaccines candidate, it may be
evaluated further and recommended for the clinical trials
s.amazai@yahoo.com