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J Infect Dis. 2012 May 1;205(9):1408-16. doi: 10.1093/infdis/jis212. Epub 2012 Mar 29.

Pneumococcal conjugate and plain polysaccharide vaccines have divergent effects on antigen-specific B cells.

Author information

1
Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.

Abstract

BACKGROUND:

A 23-valent unconjugated pneumococcal polysaccharide vaccine (23vP), routinely administered at the age of 65, has limited effectiveness, and revaccination induces attenuated antibody responses. It is not known whether pneumococcal polysaccharide-protein conjugated vaccines (PCV), although highly effective in infants, offer any immunological advantages over 23vP in adults.

METHODS:

We immunized adults with schedules combining both PCV and 23vP and investigated B-cell responses to establish whether PCV7 (a 7-valent PCV) induced T-dependent responses in adults, to assess the role of memory B cells in 23vP-induced antibody hyporesponsiveness, and to identify the B-cell subtypes involved.

RESULTS:

A single dose of PCV7 induced significant increases in serotype-specific memory B-cell populations in peripheral blood indicating a T-dependent response. Conversely, immunization with 23vP resulted in a decrease in memory B-cell frequency. Furthermore, memory B-cell responses to subsequent immunization with PCV7, when given after 23vP, were attenuated. Notably, B1b cells, a subset important in protecting mice against pneumococci, were also depleted following immunization with 23vP in humans.

CONCLUSIONS:

This study indicates that PCV7 may have an immunological advantage over 23vP in adults and that 23vP-induced depletion of memory and B1b-cell subsets may provide a basis for antibody hyporesponsiveness and the limited effectiveness of 23vP. Clinical Trials Registration. ISRCTN: 78768849.

PMID:
22457293
PMCID:
PMC3324398
DOI:
10.1093/infdis/jis212
[Indexed for MEDLINE]
Free PMC Article

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