Sorted B cells from mice treated with MPL and/or R837

Many successful vaccines induce persistent antibody responses that can last a lifetime. The mechanisms by which they do so remain unclear, but emerging evidence suggests that activate dendritic cells (DCs) via Toll-like receptors (TLRs). For example, the yellow fever vaccine YF-17D, one of the most successful empiric vaccines ever developed, activates DCs via multiple TLRs to stimulate pro-inflammatory cytokines. Triggering specific combinations of TLRs in DCs can induce synergistic production of cytokines, which results in enhanced T cell responses, but its impact on antibody responses remain unknown. Learning the critical parameters of innate immunity that programs such antibody responses remains a major challenge in vaccinology. We demonstrated that immunization of mice with synthetic nanoparticles containing antigens plus Toll-like receptor (TLR) ligands 4 (MPL) + 7 (R837) induces synergistic increases in antigen-specific, neutralizing antibodies compared to immunization with a single TLR ligand. To determine whether there was any early programming of B cells, we isolated isotype switched, TCRbeta-CD11b-CD19+IgD-IgG+ B cells by FACS at 7 days post immunization with nanoparticles containing various adjuvants plus OVA, and performed microarray analyses to assess their molecular signatures.

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Kasturi SP, Skountzou I, Albrecht RA, Koutsonanos D, Hua T, Nakaya HI, Ravindran R, Stewart S, Alam M, Kwissa M, Villinger F, Murthy N, Steel J, Jacob J, Hogan RJ, García-Sastre A, Compans R, Pulendran B