Serotype-specific avidity is achieved following a single dose of the 7-valent pneumococcal conjugate vaccine, and is enhanced by 23-valent pneumococcal polysaccharide booster at 12 months

F M Russell, A Balloch, P V Licciardi, J R Carapetis, L Tikoduadua, L Waqatakirewa, Y B Cheung, E K Mulholland, M L K Tang, F M Russell, A Balloch, P V Licciardi, J R Carapetis, L Tikoduadua, L Waqatakirewa, Y B Cheung, E K Mulholland, M L K Tang

Abstract

Aim: To evaluate whether the avidity of serotype-specific IgG to pneumococcal serotypes is enhanced by an increased number of doses of the 7-valent pneumococcal conjugate vaccine (PCV) in infancy or by a 12 month 23-valent pneumococcal polysaccharide vaccine (23vPPS) booster, and/or subsequent re-exposure to a small dose of pneumococcal polysaccharide antigens (mPPS) at 17 months.

Methods: Fijian infants aged 6 weeks were recruited, stratified by ethnicity and randomized to 8 groups to receive 0, 1, 2, or 3 doses of PCV, with or without 23vPPS at 12 months. All children received mPPS at 17 months of age. Avidity of serotype-specific IgG for PCV serotypes in the first 12 months and for all 23vPPS serotypes thereafter was assessed by EIA after sodium thiocyanate elution.

Results: At one month post primary series, the 2 and 3 PCV dose groups demonstrated similar avidity, with the single dose group tending to have lower avidity. However, by age 9 months, the single dose group had similar avidity to the 2 and 3 PCV groups for most serotypes. The 23vPPS booster enhanced affinity maturation for most serotypes and this was most marked in those groups that received a single PCV dose. There was little further increase following the mPPS.

Conclusions: By 9 months of age, similar avidity can be induced following one, 2 or 3 doses of PCV. A 23vPPS booster at 12 months enhanced affinity maturation with an increase in antibody avidity for most serotypes. Subsequent re-challenge with mPPS at 17 months did not further enhance the avidity of serotype-specific response in the 12 month 23vPPS groups.

Trial registration: ClinicalTrials.gov NCT00170612.

Copyright © 2011 Elsevier Ltd. All rights reserved.

Figures

Figure 1
Figure 1
Kinetics of the median percentage of serotype-specific-IgG that is avid for the PCV serotypes taken 4 weeks following the PCV primary series, and at 9 and 12 months of age
Figure 1
Figure 1
Kinetics of the median percentage of serotype-specific-IgG that is avid for the PCV serotypes taken 4 weeks following the PCV primary series, and at 9 and 12 months of age
Figure 2
Figure 2
Kinetics of the median percentage of serotype-specific IgG that is avid for the PCV serotypes pre and post 12 month 23vPPS and pre and post 18 month mPPS in those that did or did not receive the 12 month 23vPPS
Figure 2
Figure 2
Kinetics of the median percentage of serotype-specific IgG that is avid for the PCV serotypes pre and post 12 month 23vPPS and pre and post 18 month mPPS in those that did or did not receive the 12 month 23vPPS
Figure 3
Figure 3
Kinetics of the median percentage of serotype-specific IgG that is avid for selected non-PCV serotypes in those that did or did not receive the 12 month 23vPPS
Figure 3
Figure 3
Kinetics of the median percentage of serotype-specific IgG that is avid for selected non-PCV serotypes in those that did or did not receive the 12 month 23vPPS

Source: PubMed

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