10-valent pneumococcal non-typeable Haemophilus influenzae protein-D conjugate vaccine (PHiD-CV) induces memory B cell responses in healthy Kenyan toddlers. (10th June 2015)

• Record Type: Journal Article
• Authors: Muema, D M; Nduati, E W; Uyoga, M; Bashraheil, M; Scott, J A G; Hammitt, L L; Urban, B C
• Is Part Of: Clinical and experimental immunology. Volume 181:Number 2(2015:Aug.)
• Page Start: 297
• Page End: 305
• Publication Date: 2015-06-10
• Subjects: children -- ELISPOT -- memory B cells -- PHiD-CV -- pneumococcal conjugate vaccines; Immunopathology -- Periodicals; 616.079
• DOI: 10.1111/cei.12637
• Languages: English
• ISSNs: 0009-9104

Abstract

Summary: Memory B cells are long-lived and could contribute to persistence of humoral immunity by maintaining the plasma-cell pool or making recall responses upon re-exposure to an antigen. We determined the ability of a pneumococcal conjugate vaccine to induce anti-pneumococcal memory B cells. Frequencies of memory B cells against pneumococcal capsular polysaccharides from serotypes 1, 6B, 14, 19F and 23F were determined by cultured B cell enzyme-linked immunospot (ELISPOT) in 35 children aged 12–23 months who received pneumococcal non-typeable Haemophilus influenzae protein-D conjugate vaccine (PHiD-CV). The relationships between plasma antibodies and memory B cell frequencies were also assessed. After two doses of PHiD-CV, the proportion of subjects with detectable memory B cells against pneumococcal capsular polysaccharides increased significantly for serotypes 1 (3–45%; P < 0·01), 19F (21–66%; P < 0·01) and 23F (13–36%; P = 0·02), but not serotypes 6B (24–42%; P = 0·24) and 14 (21–40%; P = 0·06). Correlations between antibodies and memory B cells were weak. Carriage of serotype 19F at enrolment was associated with poor memory B cell responses against this serotype at subsequent time-points (day 30: non-carriers, 82% versus carriers, 0%, P < 0·01; day 210: non-carriers, 72% versus carriers, 33%, P = 0·07). PHiD-CV is capable of inducing memory B cells against some of the component pneumococcal capsular polysaccharides.