Effect of conjugation methodology on the immunogenicity and protective efficacy of meningococcal group C polysaccharide-P64k protein conjugates.
Neisseria meningitidis serogroup C polysaccharide (CCPS) was conjugated to the carrier protein P64k using two different conjugation procedures, condensation mediated by carbodiimide with adipic acid dihydrazide as spacer and the reductive amination method. BALB/c mice were immunized with the resultant polysaccharide-protein conjugates and the immune response was evaluated. All conjugates assayed generated at least 10-fold higher antibody titers than the free polysaccharide. The reductive amination method rendered the best conjugate (CCPS-P64kR) that was able to elicit antibody titers statistically higher than the titer elicited by the plain CCPS (P<0.001). The sera of the group immunized with CCPS-P64kR showed a three-fold higher bactericidal response than the sera of the group immunized with the plain CCPS and they were able to protect against challenge with meningococci in the infant rat protection model. In addition, three different conjugates were obtained from polysaccharides with molecular relative sizes of 2000-4000 Da, 4000-10,000 Da or 10,000-50,000 Da, but no differences were detected in the immune response obtained against the three conjugates. Our experiments demonstrate that it is possible to generate a protective, T-cell-dependent response against CCPS using the P64k protein as carrier.
Carmenate
Tania
T
Centre for Genetic Engineering and Biotechnology, Division of Vaccines, PO Box 6162, Havana 6, Cuba. tania@fq.uh.cu
Canaán
Leonardo
L
Alvarez
Anabel
A
Delgado
Maité
M
González
Sonia
S
Menéndez
Tamara
T
Rodés
Lorenzo
L
Guillén
Gerardo
G
D000272:Adipates; D000586:Amination; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000276:immunology*; D002234:Carbodiimides; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D007074:Immunoglobulin G / Q000097:blood; D008589:Meningococcal Infections / Q000276:immunology* / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D038542:Neisseria meningitidis, Serogroup C / Q000254:growth & development / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000276:immunology*; D051381:Rats; D018074:Vaccines, Conjugate / Q000737:chemistry / Q000276:immunology
D000272:Adipates; D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002234:Carbodiimides; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D011135:Polysaccharides, Bacterial; D018074:Vaccines, Conjugate; C112623:lpdA protein, Neisseria meningitidis; C037676:meningococcal group C polysaccharide; C010011:adipic dihydrazide