Figure 2.

AID Reporter System Identifies LCMV-Specific B Cells in a Polyclonal Response

(A–C) We infected AID^rep mice with rCl13 or VSV on day 0 or left them uninfected. TAM was administered on days 0, 5, and 10, as schematically shown in (A). LCMV-NP binding by splenic EYFP⁺ GL7⁺ B cells was analyzed on day 50 (B and C). Panel (B) shows a representative FACS plot with numbers indicating the percentage of gated cells, as quantified in (C). For gating strategy, see Figure S2.

(D–F) We infected AID^rep mice with rCl13 or Vacc on day 0 and treated them with tamoxifen on days 0, 5, and 10, as schematically shown in (D). On day 30, we purified B cells from spleen by magnetic cell separation and transferred them into syngeneic C57BL/6 recipients, which had been infected with rCl13 6 days before (day 24) or with Vacc 3 days earlier (day 27). Six days after transfer (day 36), we measured the expansion and plasma cell differentiation of proliferated (CTV^lo) adoptively transferred EYFP-reporting B cells in the spleen (E and F). Two distinct EYFP⁺ ASC populations in (E) correspond to different stages of maturation. EYFP-reporting cells were enumerated in (F). Representative FACS plots are gated on EYFP⁺ B220⁺ CD138⁻ GL7⁺ B cells (B) and on recipient (CD45.2⁺) lymphocytes in black with EYFP⁺ CTV^lo donor cells overlaid in green (E), respectively (see Figure S2). Numbers in FACS plots represent percentages of gated cells among EYFP⁺ B220⁺ CD138- GL7⁺ B cells.

Bars represent means ± SEM, n = 3–4 (C) and n = 4 (F). N = 2. One-way ANOVA with Bonferroni’s post-test for multiple comparisons (C). Two-way ANOVA with Bonferroni’s post-test for multiple comparisons (F). ^∗∗p < 0.01 comparing B cells; ^##p < 0.01 comparing ASCs, respectively. See also Figure S2.