Abstract
BACKGROUND. Despite the availability of effective vaccines, pneumococcal disease remains a major global health concern. Pneumococcal conjugate vaccines (PCVs) have progressively increased in valency, a change associated with reduced antibody titers against individual polysaccharide antigens. Whether increasing vaccine valency affects B cell responses through antigenic competition remains incompletely understood. We investigated pneumococcal polysaccharide-specific B cell responses in peripheral blood and vaccine draining lymph nodes following vaccination with PCV13. METHODS. Healthy adults (n = 5) received PCV13. Peripheral blood and lymph node fine needle aspirations (FNA) were collected longitudinally at baseline and after vaccination. Pneumococcal polysaccharide-specific B cell responses, polysaccharide-specific antibody responses and opsonophagocytic activity were analyzed in peripheral blood and draining lymph nodes. RESULTS. Antigen-specific memory B cells in peripheral blood expanded rapidly and peaked 2 weeks after vaccination. In contrast, germinal center formation in lymph nodes was delayed, peaking at 4 weeks. Germinal center B cell responses were dominated by a limited number of polysaccharide specificities, whereas the expansion of memory B cells in peripheral blood was more evenly distributed across specificities. Polysaccharide-specific antibodies followed similar dynamics in plasma and FNA supernatant. CONCLUSION. Adult immune responses to PCV are characterized by robust extrafollicular memory B cell expansion and delayed germinal center responses. The restricted specificity of germinal center B cells provides evidence for antigenic competition during germinal center formation, with potential implications for the design and immunogenicity of multivalent vaccines. TRIAL REGISTRATION. EU CT number 2022-501519-15-00. FUNDING. LUMC PhD Fellowship, ZonMW Vidi and ZonMW Clinical Fellowship.
Authors
David W. de Vos, Marina Johnson, Dennis Hoving, Giovanni E. Loe-Sack-Sioe, Catherina Kienhuis, Els L. van Persijn van Meerten, David Goldblatt, Leo G. Visser, Anna H.E. Roukens, Simon P. Jochems
