Fig 1: B cells promote primary CD8 T cell responses to subunit vaccines(A) Total splenic B220+CD19+ B cells from WT C57BL/6 mice 0–7 days after i.v. administration of combined-adjuvant vaccine (anti-CD40, poly(I:C), and OVA).(B–D) 200 CD45.1+ OT1 T cells were transferred into WT or μMT−/− mice 1 day before combined-adjuvant vaccination. Spleens were harvested 7 days later. (B) Representative tetramer and CD45.1 staining. (C) Total OT1 cells (left) and tetramer+ endogenous CD8 T cells (right). (D) Tetramer as a percentage of endogenous CD8 T cells.(E) Representative immunofluorescent staining of 2 naive mice per group with DAPI (blue), CD3 (yellow), B220 (magenta), and CD169 (green). Scale bar represents 50 μm for all images.(F) Total splenic B220+CD19+ B cells from WT or MD4 mice 0–7 days after combined-adjuvant vaccine.(G and H) Total splenic tetramer+ CD8 T cells (top) or tetramer+ cells as a percentage of CD8 T cells (bottom) were measured 7 days after subunit vaccination or infection. (G) Ag-specific CD8 T cell responses after i.v. (left) or s.c. (right) administration of combined-adjuvant + OVA vaccine. (H) Responses after i.v. subunit immunization with the single adjuvants poly(I:C) (left) or Pam3Cys (right).(I) Responses after i.p. administration of OVA emulsified in alum.(J) Responses after infection with LM-OVA.Data shown are means ± SEM; n ≥ 3 mice per group, representative of ≥ 2 experiments, except for (F) and (H), which are from one experiment each. Significance was defined by two-tailed, unpaired Student’s t tests, where *p < 0.05, **p < 0.01, and ***p < 0.001.See also Figure S2.