Demonstration of immunologic memory using serogroup C meningococcal glycoconjugate vaccine.
BACKGROUND
Studies of glycoconjugate vaccines have traditionally used an immune challenge with a plain polysaccharide vaccine to demonstrate immunologic memory. Plain polysaccharide vaccines are poorly immunogenic in children and can induce subsequent immunologic hyporesponsiveness. We therefore assessed the use of glycoconjugate vaccines as an alternative method of demonstrating immunologic memory.


METHODS
Children immunized with hepatitis B vaccine or serogroup C meningococcal glycoconjugate vaccine (MenCC) at age 2, 3, 4 months received a plain polysaccharide meningococcal serogroup A/C vaccine (MenACP) or MenCC at age 12 months. A post hoc analysis of serum bactericidal activity responses to MenCC assessed whether this differed in MenCC primed and MenCC naive infants.


RESULTS
MenCC primed children displayed higher geometric mean serum bactericidal titers than MenCC naive children following MenACP (1518 compared with 30; P = 0.003). A similar difference was seen after a dose of MenCC to toddlers (MenCC primed: 8663, MenCC naive: 710; P < 0.001). The latter comparison became a borderline significance after adjusting for higher pretoddler immunization serum bactericidal geometric mean titers in the MenCC primed group (P = 0.068).


CONCLUSIONS
Administration of glycoconjugate vaccines provides an important alternative method of demonstrating immunologic memory, avoiding the use of plain polysaccharide vaccines that are potentially deleterious in children. This has implications for the design of all future clinical trials of glycoconjugate vaccines.
Snape
Matthew D
MD
Department of Paediatrics, University of Oxford, Oxford, UK. matthew.snape@paediatrics.ox.ac.uk
Maclennan
Jenny M
JM
Lockhart
Stephen
S
English
Mike
M
Yu
Ly-Mee
LM
Moxon
Richard E
RE
Pollard
Andrew J
AJ
D000907:Antibodies, Bacterial / Q000097:blood; D001770:Blood Bactericidal Activity; D004311:Double-Blind Method; D005260:Female; D017325:Hepatitis B Vaccines / Q000276:immunology; D006801:Humans; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory / Q000276:immunology*; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D013997:Time Factors
D000907:Antibodies, Bacterial; D017325:Hepatitis B Vaccines; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; C410218:serogroup C meningococcal conjugate vaccine