Serum samples from infants vaccinated with a pneumococcal conjugate vaccine, PncT, protect mice against invasive infection caused by Streptococcus pneumoniae serotypes 6A and 6B

Eirikur Saeland, Håvard Jakobsen, Gunnhildur Ingolfsdottir, Sigurveig T. Sigurdardottir, Ingileif Jonsdottir

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38 Citations (Scopus)

Abstract

Streptococcus pneumoniae serogroup 6 is an important cause of respiratory tract disease worldwide. Vaccination with 6B polysaccharide induces antibody response to the cross-reacting serotype 6A, but the protective capacity of 6A antibodies induced in infants remains unknown. In this study, passive immunization with serum samples obtained from infants vaccinated with an octavalent polysaccharide protein conjugate vaccine, PncT, protected mice against bacteremia and/or lung infection caused by intranasal challenge with serotypes 6B and 6A. Protective infant serum samples had significantly higher serotype-specific IgG levels and opsonic activity than did nonprotective serum samples. The protective level to either serotype was ∼1/μg of specific IgG antibodies injected per mouse (corresponding to ∼0.3/μg/mL). The protection was strongly related to opsonophagocytic antibody levels measured in vitro. These results demonstrate that PncT induces antibodies in infants that protect mice against invasive disease caused by the homologous serotype and by the cross-reacting serotype 6A.

Original languageEnglish
Pages (from-to)253-260
Number of pages8
JournalJournal of Infectious Diseases
Volume183
Issue number2
DOIs
Publication statusPublished - 15 Jan 2001

Bibliographical note

Funding Information:
Financial support: Icelandic Research Council graduate student fund; University of Iceland research fund; Aventis Pasteur.

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